Comparison of Analgesic Efficacy of Dexmedetomidine and Midazolam as Adjuncts to Lignocaine for Intravenous Regional Anesthesia

Background:

Intravenous regional anesthesia (IVRA) is safe, technically simple, and cost-effective technique compared to general anesthesia with success rates of 94–98% for upper and lower limb surgeries. The main disadvantage of this procedure is its limited duration for surgery, lack of postoperative analgesia, and tourniquet pain. To overcome this disadvantage, various adjuvants to lignocaine have been studied from time to time.

Aim:

To compare the analgesic efficacy of dexmedetomidine and midazolam as adjuncts to lignocaine for IVRA for forearm and hand surgeries.

Setting and Design:

The study was conducted by the Department of Anaesthesia of Medical College and patients posted for elective as well as the emergency forearm and hand surgeries were included in the study. It was a prospective comparative study.

Materials and Methods:

Sixty patients of either sex belonging to the American Society of Anesthesiologists Class I and II, in the age range of 18–65 years, scheduled for upper limb orthopedic surgery, either elective or emergency, were included in the study. All patients were administered IVRA in this prospective, double-blind, randomized study. Patients enrolled in the study were randomly divided into two groups of thirty each. Group M-received 40 ml of 0.5% lignocaine with midazolam 50 μg/kg and Group D-received 40 ml of 0.5% lignocaine with dexmedetomidine 1 μg/kg. Time of onset of sensory block, duration of analgesia, total dose of fentanyl given, intraoperative blood pressure, oxygen saturation, heart rate, postoperative analgesia, and adverse effects were recorded and compared between the groups.

Statistical Analysis Used:

The statistical evaluation was performed using SPSS version 17.0 software. All values were calculated with a 95% confidence interval. The parameters were expressed as mean ± standard deviation and t-test was used for comparing demographic and clinical data. For comparisons, P < 0.05 was considered statistically significant.

Results:

Mean duration of analgesia was 93 ± 28 min in dexmedetomidine group and 84 ± 28 min in midazolam group, and onset of sensory block was comparable in both groups.

Conclusion:

Dexmedetomidine and midazolam, when used as adjuvants to lignocaine for IVRA, significantly improve the intraoperative conditions by providing superior quality of block. The superiority of one over the other could not be established as midazolam produced the early onset of block and less requirement of fentanyl, whereas dexmedetomidine when added to IVRA provided longer duration of analgesia (93 ± 28 min) in comparison to midazolam (84 ± 28 min).

Comparison of oral dexmedetomidine versus oral midazolam as premedication to prevent emergence agitation after sevoflurane anaesthesia in paediatric patients

Background and Aims:

Sevoflurane is the most often used inhalational agent in paediatric anaesthesia, but emergence agitation (EA) remains a major concern. Oral midazolam and parenteral dexmedetomidine are known to be effective in controlling EA. We attempted to elucidate whether oral dexmedetomidine is better than midazolam in controlling EA.

Methods:

Prospective double-blinded study involving ninety patients aged 1–10 years, undergoing elective surgeries of <2 h of expected duration under sevoflurane general anaesthesia, randomised to receive either midazolam (Group A) or dexmedetomidine (Group B) as oral premedication was carried out to record level of sedation before induction, haemodynamic parameters and recovery time. Incidence and severity of EA, post-operative pain and requirement of rescue analgesic were assessed at 0, 5, 15, 30 and 60 min postoperatively.

Results:

Data were analysed applying Student's t-test and Chi-square test using SPSS software. Mask acceptance was better in Group B (97.8% vs. 73.4%, P < 0.001). Mean arterial pressure was lower in Group B (P < 0.001) though clinically not significant. More rescue analgesic was required in Group A (5.6% vs. 0%). There was no significant difference in adverse effects. Although there was a higher incidence of EA in Group A (Aono's score 3 and 4; 40% vs. 4.4%), none of them required intervention (paediatric anaesthesia emergence delirium score >10; 0 vs. 0).

Conclusion:

Premedication with oral dexmedetomidine provides smooth induction and recovery, reduces the EA and provides better analgesia and sedation as compared to oral midazolam.

Comparison of Oral Clonidine, Oral Dexmedetomidine, and Oral Midazolam for Premedication in Pediatric Patients Undergoing Elective Surgery

Background:

Midazolam has been commonly used orally for premedication in children. A search for a better alternative continues to overcome its side effects. Recently alpha-2 agonists, clonidine, and dexmedetomidine have been used for premedication in children.

Aim:

To study and compare the efficacy of oral clonidine, oral dexmedetomidine, and oral midazolam for premedication in pediatric surgical patients.

Settings and Design:

This prospective, randomized, double blind study was conducted in a tertiary care hospital.

Materials and Methods:

The study was conducted in ninety children of either sex, in the age group of 4–12 years and the American Society of Anesthesiologists Physical status I, posted for ophthalmic surgery. Patients were randomly allocated to one of the three groups of thirty patients each: Group M: Oral midazolam 0.5 mg/kg body weight, Group D: Oral dexmedetomidine 4 μg/kg body weight, and Group C: Oral clonidine 4 μg/kg body weight. Patients were assessed for sedation, anxiolysis, and change in heart rate and blood pressure in the preoperative area. Behavior of children at separation from parents, mask acceptance, and side effects if any were noted.

Intentional intra-arterial injection of midazolam in a patient with status epilepticus in the Intensive Care Unit

Fundamental medical care includes intravenous (IV) access which provides prompt resuscitation and reliable delivery of analgesics, antibiotics, and vasoactive medication. Difficult access populations, especially in critical area, continue to challenge providers to consider and utilize alternative means to provide IV access. Potential options under such circumstances include intramuscular, intraosseous, and intratracheal drug administration, but in extreme cases where no other options are available, intra-arterial route might be considered. We present a case where midazolam was intentionally injected intra-arterially to abort seizure activity in a patient with status epilepticus in the Intensive Care Unit.

Pethidine hydrochloride is a better sedation method for pharyngeal observation by transoral endoscopy compared with no sedation and midazolam

BACKGROUND AND AIM

Standard surveillance methods for pharyngeal cancer have not been established. We conducted a randomized controlled trial to investigate the best sedation method for pharyngeal observation using transoral endoscopy.

METHODS

In total, 120 patients who underwent surveillance or diagnostic examinations for esophageal cancer were enrolled and divided equally into three groups (no sedation, midazolam, or pethidine hydrochloride). In the midazolam group, midazolam was given i.v. maintaining a Ramsay score of 3. In the pethidine group, pethidine hydrochloride (35 mg) given i.v. Seven sites in five pharyngeal regions were observed on insertion of the endoscope, and graded (0 = poor, 1 = good). After examination, the five pharyngeal regions were scored using a seven-point scale. Primary endpoint was the total score from the five pharyngeal regions. Secondary endpoints were the proportion of the perfect score using the seven-point scale, discomfort score, and adverse events.

RESULTS

Mean total scores for the no sedation group, the midazolam group and the pethidine group were 5.7, 5.5, and 6.8, respectively (P < 0.0001). Proportion of patients with a perfect score for the no sedation group, the midazolam group and the pethidine group were 53%, 35%, and 89%, respectively (P < 0.0001). The pethidine group had better results than the other two groups. Discomfort score and adverse events were low in the pethidine group.

CONCLUSION

Pethidine hydrochloride is a feasible and safe sedation method, and was superior to no sedation and midazolam regarding pharyngeal observation of esophageal cancer patients.

The Benefit of Benzodiazepine Reduction: Improving Sedation in Surgical Intensive Care

Aims:

Sedation, as it is often required in critical care, is associated with immobilization, prolonged ventilation, and increased morbidity. Most sedation protocols are based on benzodiazepines. The presented study analyzes the benefit of benzodiazepine-free sedation.

Methods:

In 2008, 134 patients were treated according to a protocol using benzodiazepine and propofol (Group 1). In 2009, we introduced a new sedation strategy based on sufentanil, nonsteroidal anti-inflammatory drugs, neuroleptics, and antidepressants, which was applied in 140 consecutive patients (Group 2). Depth of sedation, duration of mechanical ventilation, duration of Intensive Care Unit, and hospital stay were analyzed.

Results:

Group 1 had both a longer duration of deep sedation (18.7 ± 2.5 days vs. 12.6 ± 1.85 days, P = 0.031) and a longer duration of controlled ventilation (311, 35 ± 32.69 vs. 143, 96 ± 20.76 h, P < 0.0001) than Group 2. Ventilator days were more frequent in Group 1 (653, 66 ± 98.37 h vs. 478, 89 ± 68.92 h, P = 0.128).

Conclusions:

The benzodiazepine-free sedation protocol has been shown to significantly reduce depth of sedation and controlled ventilation. Additional evidence is needed to ascertain reduction of ventilator days which would not only be of benefit for the patient but also for the hospital Management.

Evaluation of Effectiveness of Dexmedetomidine and Fentanyl-midazolam Combination on Sedation and Safety during Awake Fiberoptic Intubation: A Randomized Comparative Study

Background

Awake fiberoptic intubation (AFOI) is a recommended technique for anticipated difficult airway. An ideal regime should provide patient comfort, cooperation, amnesia, hemodynamic stability, and blunt airway reflexes and maintain a patent airway with spontaneous ventilation. The aim of our study was to compare intubation conditions between dexmedetomidine and fentanyl-midazolam combination during AFOI.

Methods

This prospective, randomized study was conducted on a total of sixty patients of the American Society of Anesthesiologists physical status I and II of either sex, in the age group of 18-60 years having predicted difficult intubation undergoing elective surgeries and the patients were allocated to two groups of thirty patients each. After premedication and topicalization of airways, dexmedetomidine group (Group I, n = 30) received dexmedetomidine 1 μg/kg over 10 min and midazolam-fentanyl group (Group II, n = 30) received fentanyl 2 μg/kg plus midazolam 0.02 mg/kg over 10 min. Adequacy of intubation condition was evaluated by cough score and postintubation score. Incidence of desaturation, hemodynamic changes, and sedation using Ramsay sedation scale were noted and compared between two groups.

Results

The demographic characteristics were comparable in the two groups (P > 0.05). The mean Ramsay sedation score in Group I was 3.13 ± 0.937 and Group II was 3.16 ± 0.949, and the comparison between two groups was statistically insignificant (P = 0.891). Cough scores and postintubation scores were favorable in dexmedetomidine group than midazolam-fentanyl group and were statistically significant with P < 0.001 and 0.0001, respectively. Group I also showed better hemodynamics and less episodes of desaturation than Group II.

Conclusions

Dexmedetomidine is more effective than midazolam-fentanyl during AFOI, as it provides better intubation condition, hemodynamic stability, and preservation of airway and spontaneous ventilation.

A Prospective Randomized Trial Comparing Dexmedetomidine and Midazolam for Conscious Sedation During Oocyte Retrieval in An In Vitro Fertilization Program

Background:

Various sedative and analgesic techniques have been used for pain relief during oocyte retrieval which is the most painful part of in vitro fertilization (IVF) procedures.

Aim:

This study aimed at comparing dexmedetomidine and midazolam for conscious sedation in women undergoing transvaginal oocyte retrieval during an IVF program.

Settings and Design:

Prospective randomized double-blinded comparative study.

Patients and Methods:

Fifty-two patients undergoing oocyte retrieval in their first IVF cycle were randomly allocated into two equal groups. The intervention started with giving fentanyl1 mcg/kg intravenous (IV) followed by paracervical block in both groups. Then, subjects in group (D) received dexmedetomidine at a loading dose of 1 μg/kg IV over 10 min followed by 0.5 μg/kg/h infusion until Ramsay Sedation Scale (RSS) reached 3–4. Patients in group (M) received a loading dose of midazolam 0.06 mg/kg IV over 10 min followed by 0.5 mg incremental doses until RSS reached 3–4.

Statistical Analysis:

Statistical analysis was performed using SPSS program version 19 and EP 16 program.

Results:

Visual analog scale scores significantly decreased in group D than group M at 5 and 10 min during the procedure (P = 0.03 and 0.01, respectively), and at 20 min during postanesthesia care unit (PACU) time (P = 0.04). Intraoperative rescue sedation by propofol and postoperative rescue analgesia by acetaminophen showed a highly significant decrease (P < 0.01) in group D compared with group M. Furthermore, the time of PACU stay was significantly less (P < 0.01) in group D (49.03 ± 12.8 min) compared to group M (62.5 ± 18.34 min). Although significant bradycardia was noted in group D (23% of patients) during the procedure (P = 0.02), no cases were reported in group M. Patient satisfaction was significantly higher in group D (P < 0.1).

Conclusion:

Dexmedetomidine is an effective analgesic alternative to midazolam during oocyte retrieval for IVF. It offered not only a shorter PACU stay without significant side effects, but also better overall patient satisfaction scores.

Comparison of Dexmedetomidine and Midazolam for Sedation in Mechanically Ventilated Patients Guided by Bispectral Index and Sedation-Agitation Scale

Background:

Mechanical ventilation and sedation are inextricably linked components of critical care that represent, what we do for the patients during their vulnerable course in Intensive Care Unit (ICU).

Aims:

The aim of this study is to compare the efficacy and safety of midazolam and dexmedetomidine in patients on mechanical ventilator with the help of Bispectral Index (BIS) monitoring and correlation of BIS with Sedation-Agitation Scale (SAS).

Settings and Design:

Prospective, observational, and comparative study.

Materials and Methods:

In this study, recruited patients were allocated into two groups of 14 patients each. Group A and Group B patients received injection dexmedetomidine and injection Midazolam, respectively. Hemodynamic parameters, time of extubation, duration of mechanical ventilation, and mortality were compared between two groups.

Statistical Analysis:

Mean and the standard deviation were calculated. Test of analysis between two groups was performed using unpaired t-test. We applied correlation technique, that is, Pearson product-moment correlation coefficient (r) to assess the correlation between BIS and SAS. It varies from + 1–0 to −1.

Results:

Heart rate and blood pressure were more stable and less in Group A than Group B. Duration of mechanical ventilation was found extremely significant between Group A (77.86 ± 5.71 h) and Group B (95.64 ± 17.00 h) (P = 0.001). There was significant difference found in the time of extubation between Group A (21 ± 6.44 h) and Group B (30.4 ± 10.62 h) P = 0.008.

Conclusion:

It is concluded in this study that sedation with dexmedetomidine resulted in quick extubation and decreased the duration of mechanical ventilation in comparison to midazolam in ICU patients. There was found moderate to high correlation between BIS index and SAS.

Comparative evaluation of midazolam, dexmedetomidine, and propofol as Intensive Care Unit sedatives in postoperative electively ventilated eclamptic patients

Background and Aims:

Eclampsia is a common hypertensive disorder of pregnancy and treatment often includes termination of pregnancy with elective postoperative mechanical ventilation. The present study was aimed to compare midazolam, propofol, and dexmedetomidine for sedation and antihypertensive requirements of such patients admitted to Intensive Care Unit (ICU) after termination of pregnancy.

Material and Methods:

A total of ninety eclamptic patients administered general anesthesia for the termination of pregnancy through cesarean section and who also required postoperative ventilation were taken up for the study and were randomly allocated into three groups. All patients received MgSO4 (loading dose, 4 g intravenous) following first seizure episode followed by a continuous infusion for next 24 h. Midazolam group (GrM) received 0.05 mg/kg loading dose of midazolam, followed by infusion of 0.05–0.3 mg/kg/h, propofol group (GrP) received 1 mg/kg loading dose of propofol followed by infusion of 2–8 mg/kg/h, and dexmedetomidine group (GrD) received dexmedetomidine loading dose at 1 mcg/kg followed by infusion of 0.2–1.2 mcg/kg/h. Postoperatively, patients were assessed for hemodynamic stability, requirement of antihypertensive and analgesics, duration of sedation and stop sedation-discharge, and total time spent in the ICU.

Results:

Mean heart rate and mean arterial pressure recorded at different time intervals were lowest in GrD. Nearly 70% (n = 21) patients in the GrM required antihypertensive, 50% (n = 15) in GrP, and 36.6% (n = 11) in the GrD (P < 0.05). Duration of stop sedation-discharge from ICU was least in GrD. A number of patients demanding additional analgesics was also least in GrD.

Conclusion:

Sedation with dexmedetomidine produced better hemodynamic stability in eclamptic patients, and there was a significant reduction in requirement of additional analgesics (P = 0.035) and antihypertensive (P = 0.004). Total duration of ICU stay was also less in this group of patients.

Structural basis for regiospecific midazolam oxidation by human cytochrome P450 3A4

Human cytochrome P450 3A4 (CYP3A4) is a major hepatic and intestinal enzyme that oxidizes more than 60% of administered therapeutics. Knowledge of how CYP3A4 adjusts and reshapes the active site to regioselectively oxidize chemically diverse compounds is critical for better understanding structure-function relations in this important enzyme, improving the outcomes for drug metabolism predictions, and developing pharmaceuticals that have a decreased ability to undergo metabolism and cause detrimental drug-drug interactions. However, there is very limited structural information on CYP3A4-substrate interactions available to date. Despite the vast variety of drugs undergoing metabolism, only the sedative midazolam (MDZ) serves as a marker substrate for the in vivo activity assessment because it is preferentially and regioselectively oxidized by CYP3A4. We solved the 2.7 Å crystal structure of the CYP3A4-MDZ complex, where the drug is well defined and oriented suitably for hydroxylation of the C1 atom, the major site of metabolism. This binding mode requires H-bonding to Ser119 and a dramatic conformational switch in the F-G fragment, which transmits to the adjacent D, E, H, and I helices, resulting in a collapse of the active site cavity and MDZ immobilization. In addition to providing insights on the substrate-triggered active site reshaping (an induced fit), the crystal structure explains the accumulated experimental results, identifies possible effector binding sites, and suggests why MDZ is predominantly metabolized by the CYP3A enzyme subfamily.

Pharmacokinetics and pharmacodynamics of a new highly concentrated intranasal midazolam formulation for conscious sedation

AIM

To evaluate the pharmacokinetics, pharmacodynamics, nasal tolerance and effects on sedation of a highly concentrated aqueous intranasal midazolam formulation (Nazolam) and to compare these to intravenous midazolam.

METHODS

In this four-way crossover, double-blind, double-dummy, randomized, placebo-controlled study, 16 subjects received 2.5 mg Nazolam, 5.0 mg Nazolam, 2.5 mg intravenous midazolam or placebo on different occasions. Pharmacokinetics of midazolam and α-hydroxy-midazolam were characterized and related to outcome variables for sedation (saccadic peak velocity, the Bond and Lader visual analogue scale for sedation, the simple reaction time task and the observer's assessment of alertness/sedation). Nasal tolerance was evaluated through subject reporting, and ear, nose and throat examination.

RESULTS

Nazolam bioavailability was 75%. Maximal plasma concentrations of 31 ng ml^-1 (CV, 42.3%) were reached after 11 min (2.5 mg Nazolam), and of 66 ng ml^-1 (coefficient of variability, 31.5%) after 14 min (5.0 mg Nazolam). Nazolam displayed a significant effect on OAA/S scores. Sedation onset (based on SPV change) occurred 1 ± 0.7 min after administration of 2.5 mg intravenous midazolam, 7 ± 4.4 min after 2.5 mg Nazolam, and 4 ± 1.8 min after 5 mg Nazolam. Sedation duration was 118 ± 95.6 min for 2.5 mg intravenous midazolam, 76 ± 80.4 min for 2.5 mg Nazolam, and 145 ± 104.9 min for 5.0 mg Nazolam. Nazolam did not lead to nasal mucosa damage.

CONCLUSIONS

This study demonstrates the nasal tolerance, safety and efficacy of Nazolam. When considering the preparation time needed for obtaining venous access, conscious sedation can be achieved in the same time span as needed for intravenous midazolam. Nazolam may offer important advantages in conscious sedation.

Successful treatment of severe baclofen toxicosis initially refractory to conventional treatment

After ingesting a dose of baclofen thought to be lethal, a patient with severe neurologic signs was successfully managed despite initially being refractory to treatment. Patients with persistent neurologic abnormalities may still have an excellent prognosis despite lack of initial response. Additionally, we present a potential case of benzodiazepine withdrawal.

Caffeine combined with sedative/anesthetic drugs triggers widespread neuroapoptosis in a mouse model of prematurity

OBJECTIVES

Caffeine (CAF) and sedative/anesthetic drugs (SADs) are often coadministered to premature infants in the neonatal intensive care unit (NICU). While SAD neurotoxicity in the developing brain is well established, it is not fully clear whether CAF interacts with SADs and whether this interaction is detrimental. Using a mouse model of prematurity, we hypothesized that CAF would increase apoptotic neurotoxicity when coadministered with SADs.

METHODS

Postnatal day 3 mice were treated with vehicle or 80 mg/kg CAF prior to challenge with 6 mg/kg midazolam, 40 mg/kg ketamine, or 40 μg/kg fentanyl. Six hours later, pups were sacrificed for activated caspase 3 (AC3) immunohistochemistry, and number of AC3 positive cells per mm³ throughout neocortex, hippocampus, caudate, thalamus, and colliculi was analyzed.

RESULTS

CAF caused a statistically significant increase in AC3 positive cells when coadministered with midazolam (p = 0.002), ketamine (p = 0.014), or fentanyl (p < 0.001). Our composite dataset suggests that the addition of CAF to these SADs has a supra-additive effect, causing more neurotoxicity than expected.

CONCLUSIONS

CAF may augment the neurotoxic action of SADs indicated for neonatal sedation/anesthesia in the NICU by triggering widespread apoptosis in the developing brains of premature infants.

Scaling clearance in paediatric pharmacokinetics: All models are wrong, which are useful?

Linked Articles

This article is commented on in the editorial by Holford NHG and Anderson BJ. Why standards are useful for predicting doses. Br J Clin Pharmacol 2017; 83: 685–7. doi: 10.1111/bcp.13230

Aim

When different models for weight and age are used in paediatric pharmacokinetic studies it is difficult to compare parameters between studies or perform model‐based meta‐analyses. This study aimed to compare published models with the proposed standard model (allometric weight^0.75 and sigmoidal maturation function).

Methods

A systematic literature search was undertaken to identify published clearance (CL) reports for gentamicin and midazolam and all published models for scaling clearance in children. Each model was fitted to the CL values for gentamicin and midazolam, and the results compared with the standard model (allometric weight exponent of 0.75, along with a sigmoidal maturation function estimating the time in weeks of postmenstrual age to reach half the mature value and a shape parameter). For comparison, we also looked at allometric size models with no age effect, the influence of estimating the allometric exponent in the standard model and, for gentamicin, using a fixed allometric exponent of 0.632 as per a study on glomerular filtration rate maturation. Akaike information criteria (AIC) and visual predictive checks were used for evaluation.

Results

No model gave an improved AIC in all age groups, but one model for gentamicin and three models for midazolam gave slightly improved global AIC fits albeit using more parameters: AIC drop (number of parameters), –4.1 (5), –9.2 (4), –10.8 (5) and –10.1 (5), respectively. The 95% confidence interval of estimated CL for all top performing models overlapped.

Conclusion

No evidence to reject the standard model was found; given the benefits of standardised parameterisation, its use should therefore be recommended.

Sedative-hypnotic effects of midazolam in goats after intravenous and intramuscular administration

OBJECTIVE

To examine the effect of dose and route of administration on the sedative-hypnotic effects of midazolam.

DESIGN

Prospective randomized controlled study ANIMALS: Six indigenous, African bred goats.

METHODS

Pilot studies indicated that the optimum dose of midazolam for producing sedation was 0.6 mg kg^-1 for intramuscular (IM) injection, while the optimum intravenous (IV) doses causing hypnosis without, and with loss of palpebral reflexes were 0.6 mg kg^-1 and 1.2 mg kg^-1, respectively. These doses and routes of administration were compared with a saline placebo in a randomized block design in the main experiment, and the sedative-hypnotic effects evaluated according to pre-determined scales.

RESULTS

Intramuscular midazolam produced sedation with or without sternal recumbency in all animals with the peak effect occurring 20 minutes after administration. The scores for IM sedation with midazolam were significantly different (p < 0.05) from placebo. Intravenous midazolam at 0.6 mg kg^-1 resulted in hypnosis, and at 1.2 mg kg^-1 increased reflex suppression was observed. The maximum scores for hypnosis at both doses were obtained 5 minutes after IV injection. The mean (± SD) duration of lateral recumbency was 10.8 (± 3.8) minutes after IV midazolam (0.6 mg kg^-1) compared to 20 (± 5.2) minutes after midazolam at 1.2 mg kg^-1. Compared to baseline, the heart rate increased significantly (p < 0.05) after high dose IV midazolam.

CONCLUSION

Intramuscular midazolam (0.6 mg kg^-1) produced maximum sedation 20 minutes after injection. Intravenous injection produced maximum hypnosis within 5 minutes. Increasing the IV dose from 0.6 to 1.2 mg kg^-1 resulted in increased reflex suppression and duration of hypnosis.

CLINICAL RELEVANCE

For a profound effect with rapid onset midazolam should be given IV in doses between 0.6 and 1.2 mg kg^-1.

A comparison of propofol and midazolam/meperidine sedation in upper gastrointestinal endoscopy

INTRODUCTION

There is increasing interest in sedation for upper gastrointestinal endoscopy (UGE). Prospective randomized studies comparing sedation properties and complications of propofol and midazolam/meperidine in upper gastrointestinal endoscopy (UGE) are few.

AIM

To compare propofol and midazolam/meperidine sedation for UGE in terms of cardiopulmonary side effects, patient and endoscopist satisfaction and procedure-related times.

MATERIAL AND METHODS

This was a prospective, randomized, double-blind study of propofol versus midazolam and meperidine in 100 patients scheduled for diagnostic upper gastrointestinal endoscopy. The patients were divided into propofol and midazolam/meperidine groups. Randomization was generated by a computer. Cardiopulmonary side effects (hypotension, bradycardia, hypoxemia), procedure-related times (endoscopy time, awake time, time to hospital discharge), and patient and endoscopist satisfaction were compared between groups.

RESULTS

There was no significant difference between the groups with respect to the cost, endoscopy time, or demographic and clinical characteristics of the patients. Awake time and time to hospital discharge were significantly shorter in the propofol group (6.58 ±4.72 vs. 9.32 ±4.26 min, p = 0.030 and 27.60 ±7.88 vs. 32.00 ±10.54 min, p = 0.019). Hypotension incidence was significantly higher in the propofol group (12% vs. 0%, p = 0.027). The patient and endoscopist satisfaction was better with propofol.

CONCLUSIONS

Propofol may be preferred to midazolam/meperidine sedation, with a shorter awake and hospital discharge time and better patient and endoscopist satisfaction. However, hypotension risk should be considered with propofol, and careful evaluation is needed, particularly in cardiopulmonary disorders.

Premedication with midazolam prior to cesarean delivery in preeclamptic parturients: A randomized controlled trial

Background:

Anxiety is a concern in obstetrics, especially in preeclamptic mothers. Sedation is not commonly used in parturients for fear of adverse neonatal effect. We investigated maternal and neonatal outcome of midazolam as an adjuvant to spinal anesthesia for elective cesarean delivery.

Methods:

A prospective randomized controlled trial, in which eighty preeclamptic parturients received either an intravenous dose of 0.035 mg/kg of midazolam or an equal volume of normal saline, 30 min before spinal anesthesia. Maternal anxiety was assessed using Amsterdam Preoperative Anxiety and Information Scale (APAIS); postoperative maternal satisfaction was assessed using Maternal Satisfaction Scale for Cesarean Section (MSSCS). Newborns were assessed using Apgar score, Neonatal Neurologic and Adaptive Capacity Score (NACS), and umbilical artery blood gases.

Results:

Mothers premedicated with midazolam showed a lower level of preoperative anxiety and a higher degree of postoperative satisfaction than the control group. There were no between-group differences regarding the neonatal outcome.

Conclusion:

Preeclamptic parturients premedicated with midazolam (0.035 mg/kg) before spinal anesthesia have lower anxiety and higher postoperative satisfaction levels, with no adverse effects on the newborns.

Efficacy and safety of propofol versus midazolam in fiberoptic endotracheal intubation

Background:

Fiberoptic intubation is a technique commonly used for difficult airways. Conscious sedation is desirable to make this procedure tolerable, and it is essential that patients are cooperative, relaxed, and comfortable especially when difficult airway anatomy or pathology is encountered.

Objective:

To compare the safety and efficacy of propofol versus midazolam in oral fiberoptic endotracheal intubation in terms of hemodynamic changes, level of sedation, ease of intubation, and patient comfort and complications.

Materials and Methods:

In a prospective randomized study, 60 patients of age group 18–60 years and American Society of Anesthesiologists health classification of I and II with anticipated difficult intubation were randomly allocated into two groups. Both the groups were premedicated with injection glycopyrrolate 0.005 mg/kg and injection butorphanol 1 mg and nebulized with 4 ml of 4% lignocaine starting 20 min before the surgery. After that patients in Group I received intravenous propofol 1–2 mg/kg to a maximum of 2 mg/kg followed by 20 mg increments if needed and Group II received 0.05 mg/kg midazolam followed by 2 mg increments till the adequate level of sedation was reached. Patients were monitored for hemodynamic parameters, sedation according to observer's assessment of alertness score, intubation score, intubation time, patient comfort, satisfaction score, and complications, if any. Results were statistically analyzed.

Results:

The mean sedation score, patient comfort score, and patient satisfaction were greater in propofol group (P < 0.05) but there were no significant differences in hemodynamics, intubating conditions, and complications.

Conclusion:

We conclude that compared with midazolam, propofol provides better sedation for fiberoptic endotracheal intubation and better patient comfort and satisfaction.

Comparison of Haloperidol Alone and in Combination with Midazolam for the Treatment of Acute Agitation in an Inpatient Palliative Care Service

Agitation is a very distressing problem that must be controlled as quickly as possible, but using a safe method. The authors conducted a comparison of two protocols: a combination of haloperidol and midazolam and haloperidol alone. The combination drug protocol controlled 101 out of 121 (84%) episodes of agitation with only the first dose, whereas the haloperidol alone protocol controlled 47 out of 74 (64%) episodes. This difference is statistically significant (P =.002), with a post hoc analyzed power of 0.88. The median time from the first dose to the control of agitation was 15 minutes (range: 5-210) with the combination and 60 minutes (range: 10-430) with the other protocol, P <.001. There were no complications other than some transient somnolence, mainly with the combination protocol. The authors conclude that the combination of haloperidol and midazolam is effective and safe for the control of agitation in palliative care and it is more effective than haloperidol alone. Therefore, the combination should be adopted as the preferred protocol. It would be helpful if the usefulness of this protocol is confirmed by others.

Comparative performance of oral midazolam clearance and plasma 4β-hydroxycholesterol to explain interindividual variability in tacrolimus clearance

AIMS

We compared the CYP3A4 metrics weight-corrected midazolam apparent oral clearance (MDZ Cl/F/W) and plasma 4β-hydroxycholesterol/cholesterol (4β-OHC/C) as they relate to tacrolimus (TAC) Cl/F/W in renal transplant recipients.

METHODS

For a cohort of 147 patients, 8 h area under the curve (AUC) values for TAC and oral MDZ were calculated besides measurement of 4β-OHC/C. A subgroup of 70 patients additionally underwent intravenous erythromycin breath test (EBT) and were administered the intravenous MDZ probe. All patients were genotyped for common polymorphisms in CYP3A4, CYP3A5 and P450 oxidoreductase, among others.

RESULTS

MDZ Cl/F/W, 4β-OHC/C/W, EBT and TAC Cl/F/W were all moderately correlated (r = 0.262-0.505). Neither MDZ Cl/F/W nor 4β-OHC/C/W explained variability in TAC Cl/F/W in CYP3A5 expressors (n = 29). For CYP3A5 non-expressors (n = 118), factors explaining variability in TAC Cl/F/W in a MDZ-based model were MDZ Cl/F/W (R²  = 0.201), haematocrit (R²  = 0.139), TAC formulation (R²  = 0.107) and age (R²  = 0.032; total R²  = 0.479). In the 4β-OHC/C/W-based model, predictors were 4β-OHC/C/W (R²  = 0.196), haematocrit (R²  = 0.059) and age (R²  = 0.057; total R²  = 0.312). When genotype information was ignored, predictors of TAC Cl/F/W in the whole cohort were 4β-OHC/C/W (R²  = 0.167), MDZ Cl/F/W (R²  = 0.045); Tac QD formulation (R²  = 0.036), and haematocrit (R²  = 0.032; total R²  = 0.315). 4β-OHC/C/W, but not MDZ Cl/F/W, was higher in CYP3A5 expressors because it was higher in CYP3A4*1b carriers, which were almost all CYP3A5 expressors.

CONCLUSIONS

A MDZ-based model explained more variability in TAC clearance in CYP3A5 non-expressors. However, 4β-OHC/C/W was superior in a model in which no genotype information was available, likely because 4β-OHC/C/W was influenced by the CYP3A4*1b polymorphism.

Comparison of preanesthetic sedation in pediatric patients with oral and intranasal midazolam

BACKGROUND AND AIMS

Preoperative anxiety in children leading to postoperative negative changes and long-term behavioral problems needs better preanesthetic sedation. Across the world, midazolam is the most commonly used premedicant in pediatric patients. The fact that no single route has achieved universal acceptance for its administration suggests that each route has its own merits and demerits. This study compares oral midazolam syrup and intranasal midazolam spray as painless and needleless systems of drug administration for preanesthetic sedation in children.

MATERIAL AND METHODS

With randomization, Group O (30 children): Received oral midazolam syrup 0.5 mg/kg and Group IN (30 children): Received intranasal midazolam spray 0.2 mg/kg. Every child was observed for acceptance of drug, response to drug administration, sedation scale, separation score, acceptance to mask, recovery score and side effects of drug. Data were analyzed using Student's t-test, standard error of the difference between two means and Chi-square test.

RESULTS

In Group O and IN, 15/30 children (50%) and 7/30 children (23%) accepted drug easily (P < 0.05); 4/22 children (18%) in Group O and 11/20 children (55%) in Group IN cried after drug administration (P < 0.05). In both the groups, sedation at 20 min after premedication (Group O [80%] 24/30 vs. Group IN [77%] 23/30), parental separation and acceptance to mask were comparable (P > 0.05); 12/30 children (40%) in Group IN showed transient nasal irritation.

CONCLUSION

Oral midazolam and intranasal midazolam spray produce similar anxiolysis and sedation, but acceptance of drug and response to drug administration is better with oral route.

Effect of Low-Furanocoumarin Hybrid Grapefruit Juice Consumption on Midazolam Pharmacokinetics

The objectives of this study were to investigate the effect of grapefruit juice low in furanocoumarins on CYP3A activity and to summarize previous findings of enzyme inhibition measured by the metabolism of midazolam after intake of grapefruit juice. Twelve healthy volunteers participated in a prospective, randomized, double-blinded, 3-way crossover clinical study to determine the effect of regular grapefruit juice (RGJ) and a novel, low-furanocoumarin hybrid grapefruit juice (HGJ) on the metabolism of oral midazolam, used as a probe for in vivo CYP3A activity, compared with water as a control. The RGJ was 100% hand-squeezed "Hudson" grapefruit juice, and the HGJ contained low amounts of furanocoumarin constituents. The point estimates (90% confidence intervals) for the RGJ/water midazolam AUC geometric mean ratio was 122% (107-140). The point estimate for the HGJ/water midazolam AUC ratio was within the 80% to 125% bioequivalence range, indicating an absence of interaction. This finding also prompted a systematic review of available evidence on the pharmacokinetic alteration of midazolam by grapefruit juice. Although most studies demonstrated alteration in midazolam pharmacokinetics supporting inhibition of CYP3A activity as a likely mechanism, the cohorts included in these studies and the extent of the pharmacokinetic interaction varied widely. The current study indicated grapefruit juice-drug interaction varies substantially based on patient characteristics and/or grapefruit juice product-related factors, including the amount of furanocoumarin constituents present in the juice.

A Comparison of Midazolam, Lorazepam, and Diazepam for the Treatment of Status Epilepticus in Children: A Network Meta-analysis

Midazolam, lorazepam, and diazepam were recommended as emergent initial therapy for status epilepticus. However, there are no current studies to confirm the best agent for pediatric status epilepticus. We compared the efficacy of midazolam, lorazepam, and diazepam in treating pediatric status epilepticus using a network meta-analysis method. In total, 16 randomized controlled trials containing 1821 patients were included. Nonintravenous midazolam, intravenous lorazepam, and intravenous diazepam were more successful in achieving seizure cessation when compared with nonintravenous diazepam (odds ratio = 2.23, 95% credibility interval: 1.62, 3.10; odds ratio = 2.71, 95% credibility interval: 1.25, 5.89; odds ratio = 2.65, 95% credibility interval: 1.12, 6.29; respectively). Among lorazepam, midazolam, and diazepam, midazolam had the highest probability (surface under the cumulative ranking area [SUCRA] = 0.792) of achieving seizure cessation, and lorazepam had the largest probability (surface under the cumulative ranking area = 0.4346) of being the best treatment in reduction of respiratory depression. In conclusion, nonintravenous midazolam and intravenous lorazepam were superior to intravenous or nonintravenous diazepam, and intravenous lorazepam was at least as effective as nonintravenous midazolam in treating pediatric status epilepticus.

Pharmacokinetic Evaluation of CYP3A4-Mediated Drug-Drug Interactions of Isavuconazole With Rifampin, Ketoconazole, Midazolam, and Ethinyl Estradiol/Norethindrone in Healthy Adults

This report describes the phase 1 trials that evaluated the metabolism of the novel triazole antifungal isavuconazole by cytochrome P450 3A4 (CYP3A4) and isavuconazole's effects on CYP3A4‐mediated metabolism in healthy adults. Coadministration of oral isavuconazole (100 mg once daily) with oral rifampin (600 mg once daily; CYP3A4 inducer) decreased isavuconazole area under the concentration‐time curve (AUC_τ) during a dosing interval by 90% and maximum concentration (C_max) by 75%. Conversely, coadministration of isavuconazole (200 mg single dose) with oral ketoconazole (200 mg twice daily; CYP3A4 inhibitor) increased isavuconazole AUC from time 0 to infinity (AUC_0‐∞) and C_max by 422% and 9%, respectively. Isavuconazole was coadministered (200 mg 3 times daily for 2 days, then 200 mg once daily) with single doses of oral midazolam (3 mg; CYP3A4 substrate) or ethinyl estradiol/norethindrone (35 μg/1 mg; CYP3A4 substrate). Following coadministration, AUC_0‐∞ increased 103% for midazolam, 8% for ethinyl estradiol, and 16% for norethindrone; C_max increased by 72%, 14%, and 6%, respectively. Most adverse events were mild to moderate in intensity; there were no deaths, and serious adverse events and adverse events leading to study discontinuation were rare. These results indicate that isavuconazole is a sensitive substrate and moderate inhibitor of CYP3A4.

Efficacy of midazolam as oral premedication in children in comparison to triclofos sodium

Background and Aims:

The perioperative behavioural studies demonstrate that children are at greater risk of experiencing turbulent anaesthetic induction and adverse behavioural sequelae. We aimed to compare the efficacy of midazolam 0.5 mg/kg with triclofos sodium 100 mg/kg as oral premedication in children undergoing elective surgery.

Methods:

In this prospective, randomised and double-blind study, sixty children posted for elective lower abdominal surgery were enrolled. The patients were randomly divided into midazolam group (Group M) and triclofos sodium group (Group T) of thirty each. Group M received oral midazolam 0.5 mg/kg 30 min before induction, and Group T received oral triclofos sodium 100 mg/kg 60 min before induction. All children were evaluated for level of sedation after premedication, behaviour at the time of separation from parents and at the time of mask placement for induction of anaesthesia. Mann–Whitney U-test was used for comparing the grade of sedation, ease of separation and acceptance of face mask.

Results:

Oral midazolam produced adequate sedation in children after premedication in comparison to oral triclofos (P = 0.002). Both drugs produced successful separation from parents, and the children were very cooperative during induction. No adverse effects attributable to the premedicants were seen.

Conclusions:

Oral midazolam is superior to triclofos sodium as a sedative anxiolytic in paediatric population.

Evaluation of acetylcholine, seizure activity and neuropathology following high-dose nerve agent exposure and delayed neuroprotective treatment drugs in freely moving rats

Organophosphorus nerve agents such as soman (GD) inhibit acetylcholinesterase, producing an excess of acetylcholine (ACh), which results in respiratory distress, convulsions and status epilepticus that leads to neuropathology. Several drugs (topiramate, clobazam, pregnanolone, allopregnanolone, UBP 302, cyclopentyladenosine [CPA], ketamine, midazolam and scopolamine) have been identified as potential neuroprotectants that may terminate seizures and reduce brain damage. To systematically evaluate their efficacy, this study employed in vivo striatal microdialysis and liquid chromatography to respectively collect and analyze extracellular ACh in freely moving rats treated with these drugs 20 min after seizure onset induced by a high dose of GD. Along with microdialysis, EEG activity was recorded and neuropathology assessed at 24 h. GD induced a marked increase of ACh, which peaked at 30 min post-exposure to 800% of control levels and then steadily decreased toward baseline levels. Approximately 40 min after treatment, only midazolam (10 mg/kg) and CPA (60 mg/kg) caused a significant reduction of ACh levels, with CPA reducing ACh levels more rapidly than midazolam. Both drugs facilitated a return to baseline levels at least 55 min after treatment. At 24 h, only animals treated with CPA (67%), midazolam (18%) and scopolamine (27%) exhibited seizure termination. While all treatments except for topiramate reduced neuropathology, CPA, midazolam and scopolamine showed the greatest reduction in pathology. Our results suggest that delayed treatment with CPA, midazolam, or scopolamine is effective at reducing GD-induced seizure activity and neuropathology, with CPA and midazolam capable of facilitating a reduction in GD-induced ACh elevation.

Dexmedetomidine versus midazolam as adjuvants to intrathecal bupivacaine: A clinical comparison

BACKGROUND AND AIMS

Trials are being carried out to identify an adjuvant to intrathecal bupivacaine that preferably potentiates postoperative analgesia. This prospective, randomized, double-blind study was aimed to compare the onset and duration of sensory and motor block, postoperative analgesia and adverse effects of dexmedetomidine or midazolam given with 0.5% hyperbaric bupivacaine for spinal anesthesia.

MATERIAL AND METHODS

A total of 80 patients, scheduled for vaginal hysterectomies, were randomly allocated to Group D (n = 40) to receive intrathecally 3.0 mL 0.5% hyperbaric bupivacaine +5 ug dexmedetomidine in 0.5 mL of normal saline; and Group M (n = 40) to receive 3 mL of 0.5% hyperbaric bupivacaine +2 mg midazolam in 0.4 mL (5 mg/mL) +0.1 mL normal saline. The onset, duration of sensory and motor block, time to first postoperative analgesia and side effects were noted. Power and Sample size (PS) version 3.0.0.34 was used for power and sample size calculation. Statistical analysis was performed using Microsoft (MS) Office Excel software with the Student's t-test and Chi-square test (level of significance P = 0.05).

RESULTS

Duration of sensory, motor blockade and time to the first requirement of analgesia were significantly higher in Group D. Postoperative visual analog scale was significantly less in Group D than Group M. Both groups were similar with respect to sedation, hemodynamic variables and side-effects.

CONCLUSION

Intrathecal dexmedetomidine was better adjuvant than midazolam as it produces significantly longer duration of sensory block, reduced doses of postoperative analgesic agents with comparable side-effects.

Anxiolytic Treatment Impairs Helping Behavior in Rats

Despite decades of research with humans, the biological mechanisms that motivate an individual to help others remain poorly understood. In order to investigate the roots of pro-sociality in mammals, we established the helping behavior test, a paradigm in which rats are faced with a conspecific trapped in a restrainer that can only be opened from the outside. Over the course of repeated test sessions, rats exposed to a trapped cagemate learn to open the door to the restrainer, thereby helping the trapped rat to escape (Ben-Ami Bartal et al., 2011). The discovery of this natural behavior provides a unique opportunity to probe the motivation of rodent helping behavior, leading to a deeper understanding of biological influences on human pro-sociality. To determine if an affective response motivates door-opening, rats receiving midazolam, a benzodiazepine anxiolytic, were tested in the helping behavior test. Midazolam-treated rats showed less helping behavior than saline-treated rats or rats receiving no injection. Yet, midazolam-treated rats opened a restrainer containing chocolate, highlighting the socially specific effects of the anxiolytic. To determine if midazolam interferes with helping through a sympatholytic effect, the peripherally restricted beta-adrenergic receptor antagonist nadolol was administered; nadolol did not interfere with helping. The corticosterone response of rats exposed to a trapped cagemate was measured and compared to the rats’ subsequent helping behavior. Rats with the greatest corticosterone responses showed the least helping behavior and those with the smallest responses showed the most consistent helping at the shortest latency. These results are discussed in terms of their implications for the interaction between stress and pro-social behavior. Finally, we observed that door-opening appeared to be reinforcing. A novel analytical tool was designed to interrogate the pattern of door-opening for signs that a rat’s behavior on one session influenced his behavior on the next session. Results suggest that helping a trapped rat has a greater motivational value than does chocolate. In sum, this series of experiments clearly demonstrates the fundamental role of affect in motivating pro-social behavior in rodents and the need for a helper to resonate with the affect of a victim.

Efficacy of oral ketamine compared to midazolam for sedation of children undergoing laceration repair: A double-blind, randomized, controlled trial

OBJECTIVE

To assess the efficacy of oral ketamine versus oral midazolam for sedation during laceration repair at a pediatric emergency department.

METHODS

Children between 1 and 10 years requiring laceration repair were randomly assigned to 2 groups, treated either with oral midazolam (0.7 mg/kg) or with oral ketamine (5 mg/kg).Main outcomes measured were level of pain during local anesthesia, as assessed by the parent on a 10-cm visual analog scale (VAS) and the number of children who required intravenous sedation. Secondary outcomes included VAS by physician, pain assessment by child, maximal sedation depth assessed by the University of Michigan Sedation Scale, time until University of Michigan Sedation Scale 2 or more, general satisfaction of a parent and treating physician, length of procedure, total sedation time, and the incidence of any adverse events.

RESULTS

Sixty-eight children were recruited of which 33 were girls. Average age was 5.08 ± 2.14 years. Thirty-seven children were treated with ketamine and 31 with midazolam. Parent-assessed VAS in ketamine treated patients was 5.07 ± 0.75 compared with 3.68 ± 0.7 in midazolam treated patients [mean difference = 1.39 95% confidence interval (CI) -0.47 to 3.26]. Twelve (32%) of the children treated with ketamine required the addition of IV sedation compared to only 2 children (6%) of the children treated with midazolam [odds ratio (adjusted for age and gender) 6.1, 95% CI: 1.2 to 30.5]. The rest of the measured variables were similar between the groups, with no statistical significance.

DISCUSSION

No difference in the level of pain was found between ketamine and midazolam treated patients. Compared with oral midazolam (0.7 mg/kg), oral ketamine (5 mg/kg) was associated with higher rates of sedation failure, and thus is not recommended as a single agent for oral sedation in children requiring laceration repair.

Inhibition of soluble epoxide hydrolase as a novel approach to high dose diazepam induced hypotension

CONTEXT

Hypotension is one of the dose limiting side effects of benzodiazepines (BZDs), in particular of diazepam (DZP) which is still widely used in the clinic. Currently, only one FDA approved antidote exists for BZD overdose and novel approaches are needed to improve management of DZP overdose, dependency and withdrawal.

OBJECTIVE

Here, we hypothesized that increasing bioactive lipid mediators termed epoxy fatty acids (EpFAs) will prevent hypotension, as was shown previously in a murine model of LPS-induced hypotension. Therefore, we first characterized the time and dose dependent profile of DZP induced hypotension in mice, and then investigated the reversal of the hypotensive effect by inhibiting the soluble epoxide hydrolase (sEH), an enzyme that regulates the levels of EpFAs.

MATERIALS AND METHODS

Following baseline systolic BP recording using tail cuffs, mice were administered a sEH inhibitor (TPPU) before DZP and BP was monitored. Blood and brain levels of DZP and TPPU were quantified to examine distribution and metabolism. Plasma EpFAs levels were quantified to determine TPPU target engagement.

RESULTS

In this murine model, DZP induced dose dependent hypotension which was more severe than midazolam. The temporal profile was consistent with the reported pharmacokinetics/pharmacodynamics of DZP. Treatment with TPPU reversed the hypotension resulting from high doses of DZP and decreased the sEH metabolites of EpFAs in the plasma demonstrating target engagement.

DISCUSSION AND CONCLUSION

Overall, these findings demonstrate the similarity of a murine model of DZP induced hypotension to clinical observations in humans. Furthermore, we demonstrate that stabilization of EpFAs by inhibiting sEH is a novel approach to overcome DZP-induced hypotension and this beneficial effect can be enhanced by an omega three diet probably acting through epoxide metabolites of the fatty acids.

Midazolam regulated caspase pathway, endoplasmic reticulum stress, autophagy, and cell cycle to induce apoptosis in MA-10 mouse Leydig tumor cells

PURPOSE

Midazolam is widely used as a sedative and anesthetic induction agent by modulating the different GABA receptors in the central nervous system. Studies have also shown that midazolam has an anticancer effect on various tumors. In a previous study, we found that midazolam could induce MA-10 mouse Leydig tumor cell apoptosis by activating caspase cascade. However, the detailed mechanism related to the upstream and downstream pathways of the caspase cascade, such as endoplasmic reticulum (ER) stress, autophagy, and p53 pathways plus cell cycle regulation in MA-10 mouse Leydig tumor cells, remains elusive.

METHODS

Flow cytometry assay and Western blot analyses were exploited.

RESULTS

Midazolam significantly decreased cell viability but increased sub-G1 phase cell numbers in MA-10 cells (P<0.05). Annexin V/propidium iodide double staining further confirmed that midazolam induced apoptosis. In addition, expressions of Fas and Fas ligand could be detected in MA-10 cells with midazolam treatments, and Bax translocation and cytochrome c release were also involved in midazolam-induced MA-10 cell apoptosis. Moreover, the staining and expression of LC3-II proteins could be observed with midazolam treatment, implying midazolam could induce autophagy to control MA-10 cell apoptosis. Furthermore, the expressions of p-EIF2α, ATF4, ATF3, and CHOP could be induced by midazolam, indicating that midazolam could stimulate apoptosis through ER stress in MA-10 cells. Additionally, the expressions of cyclin A, cyclin B, and CDK1 could be inhibited by midazolam, and the phosphorylation of p53, P27, and P21 could be adjusted by midazolam, suggesting that midazolam could manage cell cycle through the regulation of p53 pathway to induce apoptosis in MA-10 cells.

CONCLUSION

Midazolam could induce cell apoptosis through the activation of ER stress and the regulation of cell cycle through p53 pathway with the involvement of autophagy in MA-10 mouse Leydig tumor cells.

Semi-mechanistic autoinduction model of midazolam in critically ill patients: population pharmacokinetic analysis

WHAT IS KNOWN AND OBJECTIVE

Midazolam (MDZ) is commonly used for sedating critically ill patients. The daily dose required for adequate sedation increases in increments over 100 h after administration. The objectives of this study were to characterize the MDZ pharmacokinetics in critically ill patients and to describe the phenomenon of increasing daily dose by means of population pharmacokinetic analysis.

METHODS

Data were obtained from 30 patients treated in an intensive care unit. The patients received MDZ intravenously as a combination of bolus and continuous infusion. Serum MDZ concentration was assayed by high-performance liquid chromatography. Population pharmacokinetic analysis was performed using the NONMEM software package. The alteration of clearance unexplained by demographic factors and clinical laboratory data was described as an autoinduction of MDZ clearance using a semi-mechanistic pharmacokinetic-enzyme turnover model.

RESULTS AND DISCUSSION

The final population pharmacokinetic model was a one-compartment model estimated by incorporating a semi-mechanistic pharmacokinetic-enzyme turnover model for clearance, taking autoinduction into account. A significant covariate for MDZ clearance was total bilirubin. An increase in total bilirubin indicated a reduction in MDZ clearance. From simulation using the population pharmacokinetic parameters obtained in this study, MDZ clearance increased 2·3 times compared with pre-induced clearance 100 h after the start of 12·5 mg/h continuous infusion.

WHAT IS NEW AND CONCLUSION

Autoinduction and total bilirubin were significant predictors of the clearance of MDZ in this population. Step-by-step dosage adjustment using this population pharmacokinetic model may be useful for establishing a MDZ dosage regimen in critically ill patients.

Analgesic and Sedative Effects of Dezocine and Midazolam During Vitrectomy

PURPOSE

To evaluate the analgesic and sedative effectiveness of dezocine and midazolam in vitrectomy.

METHODS

One hundred and sixty patients undergoing vitrectomy were randomized into four groups. The control group was given local anesthetic in retrobulbar nerve block only, while the other three groups received a single dose of 0.1 mg/kg dezocine or/and 0.05 mg/kg midazolam (groups D, M, DM), respectively, at 10 min before retrobulbar block. Mean arterial pressure (MAP), heart rate (HR), and oxygen saturation (SpO₂) were recorded prior to local anesthesia (Tp), at the start of surgery (T0), 5, 15, 30 min during (T1-T3), and at the end of surgery (T4). Pain at T2 and T4 was assessed by Numeric Rating Scale (NRS). Level of sedation at T2 was assessed using the Ramsay scale. Postoperative nausea and vomiting (PONV) events were recorded for 24 h.

RESULTS

Group DM showed a decrease in HR during T0-T4 compared to Tp (p < 0.001). The MAP of all groups decreased significantly at T0 compared to Tp (p < 0.05), but remained unchanged at T1-T4. At T2, all groups have lower pain level than control (p < 0.001), while group DM showed the lowest pain level. At T4, groups D and DM showed a lower pain level than control (p < 0.01). Groups M and DM showed a higher Ramsay score than group C (p < 0.01). Compared with control, group D had a higher PONV rate (p < 0.1). Groups M and DM showed a lower PONV rate than group D (p < 0.0001), and group M had a lower PONV rate than group C (p < 0.01).

CONCLUSION

Combinatory use of dezocine and midazolam in addition to local anesthetic in retrobulbar nerve block can help relief pain and anxiety during vitrectomy and reduce PONV.

COMPARISON BETWEEN DEXMEDETOMIDINE-S-KETAMINE AND MIDAZOLAM-S-KETAMINE IN IMMOBILIZATION OF ONCILLA (LEOPARDUS TIGRINUS)

Established immobilization protocols are required for safe procedures on wildlife and zoo animals. This study evaluated the cardiovascular, respiratory, and anesthetic effects of dexmedetomidine (40 μg/kg) with S-ketamine (5 mg/kg) and midazolam (0.5 mg/kg) with S-ketamine (5 mg/kg) in 12 specimens of oncilla (Leopardus tigrinus) at Quinzinho de Barros Municipal Zoo Park in Sorocaba, São Paulo, Brazil, between January and March 2010. Each animal underwent both protocols, totaling 24 anesthetic procedures. The dexmedetomidine-S-ketamine group (DK) showed a decrease in heart rate compared to initial values and significantly lower heart rate and oxyhemoglobin saturation values compared to Midazolam-S-Ketamine Group (MK). Four animals in DK had episodes of sinus pauses. Systemic blood pressure, respiratory frequency, and rectal temperature showed no significant differences between groups. The dexmedetomidine-S-ketamine group showed a greater degree of muscle relaxation and allowed for more thorough and longer oral evaluations. The dexmedetomidine-S-ketamine group had a shorter period of recumbency, longer period to return of muscle tone, and shorter recovery time. Two animals in MK did not reach recumbency. The dexmedetomidine-S-ketamine group had better qualities of induction and recovery. It may be concluded that both protocols can be safely used in oncillas. Midazolam-S-ketamine promotes effective chemical restraint for quick and minimally invasive procedures and dexmedetomidine-S-ketamine promotes effective chemical restraint for prolonged and more invasive procedures.

Pharmacokinetic considerations and recommendations in palliative care, with focus on morphine, midazolam and haloperidol

INTRODUCTION

A variety of medications are used for symptom control in palliative care, such as morphine, midazolam and haloperidol. The pharmacokinetics of these drugs may be altered in these patients as a result of physiological changes that occur at the end stage of life.

AREAS COVERED

This review gives an overview of how the pharmacokinetics in terminally ill patients may differ from the average population and discusses the effect of terminal illness on each of the four pharmacokinetic processes absorption, distribution, metabolism, and elimination. Specific considerations are also given for three commonly prescribed drugs in palliative care: morphine, midazolam and haloperidol).

EXPERT OPINION

The pharmacokinetics of drugs in terminally ill patients can be complex and limited evidence exists on guided drug use in this population. To improve the quality of life of these patients, more knowledge and more pharmacokinetic/pharmacodynamics studies in terminally ill patients are needed to develop individualised dosing guidelines. Until then knowledge of pharmacokinetics and the physiological changes that occur in the final days of life can provide a base for dosing adjustments that will improve the quality of life of terminally ill patients. As the interaction of drugs with the physiology of dying is complex, pharmacological treatment is probably best assessed in a multi-disciplinary setting and the advice of a pharmacist, or clinical pharmacologist, is highly recommended.

Clinical study of midazolam sequential with dexmedetomidine for agitated patients undergoing weaning to implement light sedation in intensive care unit

PURPOSE

To evaluate midazolam sequential with dexmedetomidine for agitated patients undergoing weaning to implement light sedation in ICU.

METHODS

This randomized, prospective study was conducted in Tianjin Third Central Hospital, China. Using a sealed-envelope method, the patients were randomly divided into 2 groups (40 patients per group). Each patient of group A received an initial loading dose of midazolam at 0.3-3mg/kg·h 24 h before extubation, followed by an infusion of dexmedetomidine at a rate of 0.2-1 μg/kg·h until extubation. Each patient of group B received midazolam at a dose of 0.3-3 mg/kg·h until extubation. The dose of sedation was regulated according to RASS sedative scores maintaining in the range of -2-1. All patients were continuously monitored for 60 min after extubation. During the course, heart rate (HR), mean artery pressure (MAP), extubation time, adverse reactions, ICU stay, and hospital stay were observed and recorded continuously at the following time points: 24 h before extubation (T1), 12 h before extubation (T2), extubation (T3), 30 min after extubation (T4), 60 min after extubation (T5).

RESULTS

Both groups reached the goal of sedation needed for ICU patients. Dexmedetomidine was associated with a significant increase in extubation quality compared with midazolam, reflected in the prevalence of delirium after extubation (20% (8/40) vs 45% (18/40)), respectively (p= 0.017). There were no clinically significant decreases in HR and MAP after infusing dexmedetomidine or midazolam. In the group A, HR was not significantly increased after extubation; however, in the group B, HR was significantly increased compared with the preextubation values (p < 0.05). HR was significantly higher in the group B compared with the group A at 30 and 60 min after extubation (both, p <0.05). Compared with preextubation values, MAP was significantly increased at extubation in the group B (p < 0.05) and MAP was significantly higher at T3, T4, T5 in the group B than group A (p < 0.05). There was a significant difference in extubation time ((3.0 ± 1.5) d vs (4.3 ± 2.2) d, p < 0.05), ICU stay ((5.4 ± 2.1) d vs (8.0 ± 1.4) d, p < 0.05), hospital stay ((10.1 ± 3.0) d vs (15.3 ± 2.6) d, p <0.05) between group A and B.

CONCLUSION

Midazolam sequential with dexmedetomidine can reach the goal of sedation for ICU agitated patients, meanwhile it can maintain the respiratory and circulation parameters and reduce adverse reactions.

Comparative evaluation of two different loading doses of dexmedetomidine with midazolam-fentanyl for sedation in vitreoretinal surgery under peribulbar anaesthesia

Background and Aims:

Midazolam-fentanyl (MDZ:FEN) combination has been routinely used for intravenous sedation in ophthalmic surgeries. Dexmedetomidine (DEX), a recent α₂ adrenoreceptor agonist indicated for sedation for ophthalmic use at a loading dose of 0.5 μg/kg over 10 min, can cause deeper plane of sedation and surgeon dissatisfaction. Therefore, we proposed to evaluate the efficacy and safety of two different loading doses of DEX.

Methods:

In a prospective study, 60 patients aged 50-70 years, scheduled for retinal surgery under peribulbar block were divided equally to receive either MDZ:FEN or DEX 0.5 μg/kg (DEX full) or DEX 0.25 μg/kg (DEX half) loading dose over 10 min followed by titrated maintenance dose of DEX 0.25-0.4 μg/kg/h. Vital parameters, level of sedation (Ramsay Sedation Scale 1–6), effect on respiration and surgeon satisfaction were assessed at regular intervals. Surgeon satisfaction score (0–3) was noted.

Results:

‘DEX half’ group patients had predominantly stable haemodynamics, level 3 sedation and surgeon satisfaction score of 2–3 (good to excellent operating conditions). This group had no vomiting and no respiratory depression. ‘DEX full’ group had a higher incidence of bradycardia, hypotension, level 4 sedation (Ramsay Sedation Scale) and lower surgeon satisfaction. Incidence of nausea and vomiting was higher in MDZ:FEN group compared to other two groups.

Conclusion:

DEX 0.25 μg/kg loading dose over 10 min followed by titrated maintenance dose is an effective alternative to MDZ:FEN and provides controlled (level 3) sedation and stable haemodynamics maximising surgeon satisfaction. Avoiding narcotic analgesics with its associated post-operative nausea and vomiting is an additional benefit.

Dexmedetomidine versus midazolam for sedation during endoscopy: A meta-analysis

Patients undergoing endoscopy frequently require sedation, which commonly includes the administration of midazolam or dexmedetomidine. Previous meta-analyses have mainly focused on comparing the effects of these two drugs in intensive care unit patients. In the present study, randomized controlled trials (RCTs) that compared the sedative and clinical effectiveness of these two drugs in patients undergoing endoscopy were searched in a number of databases. The meta-analysis showed that dexmedetomidine demonstrated a significantly lower rate of respiratory depression and adverse events compared with those presented upon midazolam administration. A significant difference was also observed in the sedation potency of the sedatives. The current controlled data suggest that dexmedetomidine may be an alternative to midazolam in the sedation for endoscopy. However, more high-quality and well-designed studies are required to further evaluate this conclusion.

Comparative study evaluating efficacy of sufentanil versus midazolam in preventing myoclonic movements following etomidate

Background and Aims:

Myoclonus is a major side-effect following etomidate injection requiring use of medical intervention.

Material and Methods:

In this double-blinded clinical trial, 50 consecutive patients, randomly received sufentanil 0.2 μg/kg or midazolam 0.015 mg/kg, 90 s before induction of anesthesia with etomidate (0.3 mg/kg). Then, the patients were monitored for any myoclonic movements during anesthesia.

Results:

The incidence of myoclonus was 28% in the sufentanil group and 84% in the midazolam group. The frequency and intensity of myoclonus were significantly higher in the midazolam group, compared to the sufentanil group (P < 0.001). Myoclonus duration in the sufentanil and midazolam groups were 5.8 ± 13.2 and 69 ± 47.8 s, respectively (P < 0.0010).

Conclusion:

The frequency, intensity and duration of myoclonus in the midazolam group, were significantly more prevalent than the sufentanil group.

An in vivo evaluation of the change in the pulpal oxygen saturation after administration of preoperative anxiolytics and local anesthesia

Background. Given the influence of systemic blood pressure on pulpal blood flow, anxiolytics prescribed may alter the pulpal blood flow along with the local anesthetic solution containing a vasoconstrictor. This study evaluated the impact of preoperative anxiolytics and vasoconstrictors in local anesthetic agents on pulpal oxygen saturation.

Methods. Thirty anxious young healthy individuals with a mean age of 24 years were randomly selected using the Corah’s Dental Anxiety Scale (DAS). After checking the vital signs the initial pulpal oxygen saturation (initial SpO2) was measured using a pulse oximeter. Oral midzolam was administered at a dose of 7.5 mg. After 30 min, the vital signs were monitored and the pulpal oxygen saturation (anxiolytic SpO2) was measured. A total of 1.5 mL of 2% lidocaine with 1:200000 epinephrine was administered as buccal infiltration anesthesia and 10 min the final pulpal oxygen saturation (L.A SpO2) was measured.

Results. The mean initial (SpO2) was 96.37% which significantly decreased to 90.76% (SpO2) after the administration of the anxiolytic agent. This drop was later accentuated to 85.17% (SpO2) after administration of local anesthetic solution. Statistical significance was set at P<0.0001.

Conclusion. High concentrations of irritants may permeate dentin due to a considerable decrease in the pulpal blood flow from crown or cavity preparation. Therefore, maintaining optimal blood flow during restorative procedures may prevent pulpal injury.

Comparative evaluation of bispectral index system after sedation with midazolam and propofol combined with remifentanil versus ketamine in uncooperative during dental procedures

Background:

Proper analgesic agents should be used in combination with sedative agents. Remifentanil is a synthetic narcotic/analgesic agent with a short duration effect and decreases the risk of apnea during recovery. Bispectral index system (BIS) is a new noninvasive technique for the evaluation of the depth of sedation. The aim of present clinical trial was to evaluate and compare the efficacy of intravenous sedation with propofol/midazolam/remifentanil (PMR) in comparison to propofol/midazolam/ketamine (PMK) for dental procedures in children 3-7 years of age.

Materials and Methods:

In this clinical trial, 32 healthy uncooperative children who were candidates for dental treatments under sedation were randomly divided into two groups. Intravenous sedation was induced with PMR in one group and with PMK in the other group. After injection and during procedure BIS index, heart rate and respiratory rate, blood pressure, and oxygen saturation was evaluated every 5 min. After the procedure, recovery time was measured. Data were analyzed with ANOVA, Friedman, Wilcoxon, and t-test.

Results:

The BIS value was significantly low in ketamin group (P = 0.003) but respiratory rates and heart rates were same in both groups with no statistical difference (P = 0.884, P = 0.775). The recovery time was significantly shorter in remifentanil group (P = 0.008 and P = 0.003).

Conclusion:

It can be concluded that intravenous sedation technique with PMR combination induces effective and safe sedation, with less pain and more forgetfulness and a shorter recovery time for children 3-7 years of age during dental procedures.

Effects of midazolam or tramadol premedication on early cognitive function in endoscopic retrograde cholangiopancreatography (ERCP): A randomized, controlled, double-blind study

OBJECTIVE

To evaluate the sedative efficacy and effects on early period cognitive function of premedication in endoscopic retrograde cholangiopancreatography (ERCP).

METHODS

Forty patients (18-70 years; American Society of Anesthesiology risk category I-III) undergoing elective ERCP were randomized to receive oral premedication with 0.15 mg/kg midazolam or 1 mg/kg tramadol. Cognitive function was determined by mini-mental test (MMT). Target scores for effective sedation were determined as a Bispectral index score of 70-90 and modified Ramsay Sedation Scale score (mRSS) of 2-4.

RESULTS

Global MMT score was not significantly different between treatment groups at 60 min post-ERCP. A significant deterioration in the MMT subcategory of recall was determined in with midazolam versus tramadol. Level of sedation (mRSS) was higher in with midazolam compared with tramadol reaching statistical significance at 30 min after drug administration.

CONCLUSIONS

Although more effective sedation was obtained with midazolam in patients undergoing ERCP, there was a dysfunction in memory recall. It was concluded, however, that early cognitive functions were generally preserved with both drugs.

Previously published midazolam-alfentanil response surface model cannot predict patient response well in gastrointestinal endoscopy sedation

BACKGROUND

A response surface model is a mathematical model used to predict multiple-drug pharmacodynamic interactions. With the use of a previously published volunteer model, we tested the accuracy of the midazolam-alfentanil response surface model during gastrointestinal endoscopy.

METHODS

We enrolled 35 adult patients scheduled for combined endoscopic procedures. Patients were sedated with intravenous midazolam and alfentanil, and monitored with real-time auditory evoked potential. Sedation Observer's Assessment of Alertness/Sedation (OAA/S) scores were recorded by an independent observer every 2 minutes. Patients with OAA/S scores of ≥ 4 were designated as "awake". Pharmacokinetic profiles were calculated using the TIVA trainer. The published response surface model was modified to make estimations more reasonable. Patient response (OAA/S score ≥ 4 or <4) was then estimated using the modified version of the model.

RESULTS

The average procedural times were 3.3 ± 2 minutes and 6.5 ± 2.3 minutes for esophagogastroduodenoscopy and colonoscopy, respectively. The model poorly predicted patient response during gastrointestinal endoscopic procedure sedation. Accuracy in predicting an OAA/S score of <4 was 6% for the original model and 0% for the modified model. The estimated probability of loss of response ranged from 0.04% to 2.94% at the time of arousal (OAA/S score ≥ 4) and from 0.24% to 15.55% when the patient was asleep (OAA/S score < 4).

CONCLUSION

The model showed significant synergy between midazolam and alfentanil; however, it was inadequate in predicting the response of patients undergoing sedated gastrointestinal endoscopic procedures. Future model parameter adjustments are required.

Melatonin versus midazolam premedication in children undergoing surgery: A pilot study

AIM

Melatonin has been proposed as a premedication alternative to midazolam, preceding anaesthesia induction. However, to our knowledge, data concerning interaction between melatonin and intravenous anaesthetic drugs in children are not available. The aim of this prospective, randomized, double-blind pilot study was to investigate the possible effect of melatonin premedication, in comparison to midazolam, on the required infusion of propofol in children undergoing surgery. As a secondary outcome, the effect of oral melatonin on the preoperative sedation level and on the post anaesthesia recovery score was evaluated.

METHODS

Children between the age of 5 and 14 years, scheduled for elective surgery, were prospectively enrolled between January 2012 and December 2013, and randomly assigned to two groups based on whether they received oral melatonin (0.5 mg/kg) or oral midazolam (0.5 mg/kg) premedication before induction of anaesthesia with propofol. Degree of sedation before and after anaesthesia was also evaluated.

RESULTS

Ninety-two patients were studied, 46 for each group. We found that oral administration of melatonin significantly reduced doses of propofol required for induction of anaesthesia in paediatric patients, more than midazolam (P < 0.001). No statistically significant differences were found in the pre- and post-anaesthesia sedation score (P = 0.387 and P = 0.525, respectively) between the two groups.

CONCLUSIONS

The present study demonstrates that melatonin enhances the potency of propofol also in paediatric patients. Moreover, considering the paediatric level of sedation, melatonin was equally as effective as midazolam. These data support the use of melatonin as a premedicant in paediatric surgical patients.

A comparison of propofol-midazolam and midazolam alone for sedation in endobronchial ultrasound-guided transbronchial needle aspiration: a retrospective cohort study

OBJECTIVES

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a new, minimally invasive, bronchoscopic technique used in the evaluation of inthrathoracic lymph nodes.Use of sedation drugs before the procedure differs among centres. There is no standardization about sedation before EBUS-TBNA.We used a policy decision to shift from use of propofol with midazolam vs midazolam alone in a large tertiary hospital to evaluate the diagnostic yield and safety of EBUS-TBNA procedure.

METHODS

Files of all the patients who were performed EBUS-TBNA between the dates of September 2010 and May 2014 were surveyed. All the EBUS-TBNA cases were performed under sedation of propofol and midazolam with an accompanying anesthesiologist in the beginning, however, sedation is applied with midazolam without an accompanying anesthesiologist after April 2013 due to changes in sedation policy. The diagnostic yield and complication rates were compared by chi-squared analysis between two groups.

RESULTS

The files of 340 EBUS-TBNA performed patients were evaluated. Of the patients 274 eligible patients were analysed. 152 patients who fulfilled the inclusion criteria were analysed in propofol-midazolam (P) sedated group and 122 patients were analysed in midazolam (M) group. There is no statistically significant difference between two different sedated groups in terms of age and gender. Diagnostic value was detected as 77.6% in P group and 85.7% in M group and the difference was not statistically significant. No difference between complication rates of both groups was observed.

CONCLUSION

Both sedation-types for performing EBUS-TBNA showed similar diagnostic value and complication rates in our study. Propofol with midazolam application requires with an accompanying anaesthesiologist, therefore, it increases cost. EBUS-TBNA procedures had been performed in safe with no decrease in diagnostic yield under moderate sedation.

Prolonged propofol infusion for mechanically ventilated children

We retrospectively analysed 30-day mortality and duration of intubation for 8016 children ventilated for three or more days, sedated with midazolam (n = 7716) or propofol (n = 300). We matched the propensity scores of 263 pairs of children. The propensity-matched 30-day mortality (95% CI) was similar: 17/263 (6.5%) with midazolam vs. 24/263 (9.1%) with propofol, p = 0.26. Weaning from mechanical ventilation of children sedated with midazolam was slower than weaning of children sedated with propofol, subhazard ratio (95% CI) 1.43 (1.18-1.73), p < 0.001.

Fipronil Compound Consumption Presenting as Status Epilepticus

Fipronil is a broadspectrum N-phenylpyrazole insecticide with gamma-aminobutyric acid type A receptor inhibitory action causing hyperexcitability of central nervous system. There is no literature reported in the past concerning its acute toxicity in human beings. A case report is useful for workers in medical and veterinary field. Hence, we are reporting a case in which young male intoxicated with fipronil compound was presented to the emergency department for having generalized tonic-clonic seizures and subsequently with the features of delirium for few days. This patient was treated with benzodiazepines which controlled the seizures and antipsychotics were given for few days for treating the psychosis.

Injection anaesthesia with fentanyl-midazolam-medetomidine in adult female mice: importance of antagonization and perioperative care

Injection anaesthesia is commonly used in laboratory mice; however, a disadvantage is that post-anaesthesia recovery phases are long. Here, we investigated the potential for shortening the recovery phase after injection anaesthesia with fentanyl-midazolam-medetomidine by antagonization with naloxone-flumazenil-atipamezole. In order to monitor side-effects, the depth of anaesthesia, heart rate (HR), core body temperature (BT) and concentration of blood gases, as well as reflex responses, were assessed during a 50 min anaesthesia. Mice were allowed to recover from the anaesthesia in their home cages either with or without antagonization, while HR, core BT and spontaneous home cage behaviours were recorded for 24 h. Mice lost righting reflex at 330 ± 47 s after intraperitoneal injection of fentanyl-midazolam-medetomidine. During anaesthesia, HR averaged 225 ± 23 beats/min, respiratory rate and core BT reached steady state at 131 ± 15 breaths/min and 34.3 ± 0.25℃, respectively. Positive pedal withdrawal reflex, movement triggered by tail pinch and by toe pinch, still occurred in 25%, 31.2% and 100% of animals, respectively. Arterial blood gas analysis revealed acidosis, hypoxia, hypercapnia and a marked increase in glucose concentration. After anaesthesia reversal by injection with naloxone-flumazenil-atipamezole, animals regained consciousness after 110 ± 18 s and swiftly returned to physiological baseline values, yet they displayed diminished levels of locomotion and disrupted circadian rhythm. Without antagonization, mice showed marked hypothermia (22 ± 1.9℃) and bradycardia (119 ± 69 beats/min) for several hours. Fentanyl-midazolam-medetomidine provided reliable anaesthesia in mice with reasonable intra-anaesthetic side-effects. Post-anaesthetic period and related adverse effects were both reduced substantially by antagonization with naloxone-flumazenil-atipamezole.