Cardiac and CNS toxicity of levobupivacaine: strengths of evidence for advantage over bupivacaine

Comparison of Fentanyl With Midazolam As Adjuvants to Levobupivacaine in Spinal Anesthesia for Cesarean Sections: A Randomized Controlled Trial

Background and objectives Spinal anesthesia stands as a cornerstone for patients undergoing lower segment cesarean section (LSCS), offering advantages like faster onset and high block density. Levobupivacaine, known for its high potency and long-acting nature, has a slower onset. The safety of intrathecal fentanyl or midazolam is evaluated as an adjuvant to levobupivacaine in parturients. This study aims to compare the duration of postoperative analgesia provided by fentanyl or midazolam added to 0.5% hyperbaric levobupivacaine in elective cesarean sections. Secondary objectives include evaluating the onset and duration of sensory and motor blockade and the incidence of nausea and vomiting. Identifying the more effective adjuvant will help optimize spinal anesthesia protocols, improve postoperative outcomes, and enhance patient comfort and recovery. Methods This study was conducted at SRM Medical College Hospital and Research Centre, Chennai, India, over six months (May 1, 2023, to October 1, 2023). A total of 90 patients undergoing elective LSCS received spinal anesthesia in a prospective randomized double-blinded controlled trial. Patients were allocated to three groups: Group A received levobupivacaine with fentanyl, Group B received levobupivacaine with midazolam, and Group C received levobupivacaine with normal saline. Block characteristics, postoperative analgesia, hemodynamic stability, and complications were assessed. Assessments were conducted at specified time points: intraoperatively, every five minutes for the first 30 minutes, every 10 minutes for the next hour, every two hours for six hours, and every four hours up to 24 hours postoperatively. Statistical analysis utilized one-way analysis of variance (ANOVA). Results Group B (levobupivacaine with midazolam) exhibited a shorter time to sensory block onset (88 seconds) compared to Groups A and C (both 145 seconds) (p < 0.001). Group A (levobupivacaine with fentanyl) showed a shorter time to maximum motor block (p = 0.045) than Groups B and C. The sensory block duration was significantly longer in Group A (127.5 minutes) compared to Group B (60 minutes) and Group C (69 minutes) (p < 0.001). Motor block duration was also prolonged in Group A (251 minutes) compared to Group B (147 minutes) and Group C (177 minutes) (p = 0.045). The first analgesic requirement was delayed in Group A (248 minutes), whereas Groups B (115 minutes) and C (90 minutes) (p < 0.001) required more frequent analgesia. Group A experienced a higher incidence of postoperative nausea and vomiting. Conclusion Midazolam accelerated sensory block onset, while fentanyl prolonged anesthesia duration without significantly affecting motor block. Fentanyl delayed the first analgesic requirement, whereas midazolam reduced postoperative nausea, vomiting, and shivering.

Chiral Switch: Between Therapeutical Benefit and Marketing Strategy

Chirality of pharmaceutical substances is an important aspect in drug research because it determines how enantiomers will interact with chiral biological targets. Enantiomers of a chiral drug can have different pharmacokinetic and pharmacological profiles; consequently, using a single pure enantiomer instead of a racemate can enhance the effectiveness and/or safety of the treatment. The tendencies of modern pharmaceutical industry regarding the current market of chiral drugs are divided between the chiral switch of previously used racemates and the development of new enantiopure drugs. The term chiral switch refers to the replacement on the market of a previously approved racemate with its single enantiomer version. The potential advantages of chiral switch can be related to a higher therapeutic index due to better potency, selectivity and fewer adverse effects, faster onset of action and exposure of the patient to lower drug dosages. However, chiral switch is also a strategy that permits manufacturers to keep market exclusivity for chiral pharmaceuticals that have lost their patent protection, even if the pure enantiomers have not demonstrated higher effectiveness or safety profile compared with the racemates.

Local and Regional Anesthesia in Zoological Companion Animal Practice

Local anesthetics provide analgesia and can be incorporated into multimodal anesthetic protocols. They work by blocking the voltage-dependent sodium ion channels along neurons that mediate nociception. Systemically, these drugs can be cardiotoxic in a dose-dependent manner. Lidocaine and bupivacaine are the most commonly used local anesthetics and their use has been reported in all classes of vertebrates. Despite anecdotal reports to the contrary, zoologic companion animals are unlikely to be more susceptible to the cardiotoxic effects of local anesthetics than domestic small animals. Local anesthetics can be clinically useful for analgesia and anesthesia in zoologic companion animal practice.

Evaluation of Trials Comparing Single-Enantiomer Drugs to Their Racemic Precursors: A Systematic Review

IMPORTANCE

Chiral switching, a strategy in which drug manufacturers develop a single-enantiomer formulation of a drug to be substituted for a racemic formulation, allows manufacturers to maintain market exclusivity for drugs losing patent protection, even without demonstrating superior efficacy or safety.

OBJECTIVE

To identify and characterize all randomized clinical trials (RCTs) directly comparing a Food and Drug Administration (FDA)-approved single-enantiomer drug against a previously approved racemic drug for 1 or more efficacy or safety end points.

EVIDENCE REVIEW

Drugs were identified using the Drugs@FDA database. Randomized clinical trials were identified using Ovid MEDLINE (1949 to October 22, 2019), Ovid Embase (1974 to October 22, 2019), Web of Science Core Collection (all years), ClinicalTrials.gov, and Cochrane Central Registry of Controlled Trials (CENTRAL, Wiley, Issue 8 of 12, October 22, 2019). Trials were characterized as favoring the single-enantiomer or racemic drugs based on whether the primary efficacy, secondary efficacy, and safety end points achieved each study's defined significance level (eg, P < .05). Trials were characterized as favoring neither drug if no statistically significant differences were reported for any end point or if both drugs were found to be superior for 1 or more separate end points.

FINDINGS

Fifteen FDA-approved single-enantiomer drugs were identified with racemic precursors approved in the US or Europe. For 3 single-enantiomer racemic drug pairs, no RCTs directly comparing the drugs were identified. For the remaining 12 pairs, 185 RCTs comparing efficacy or safety of the drug pairs were identified, 124 (67.0%) of which studied 1 pair (levobupivacaine/bupivacaine). There were 179 RCTs directly comparing drug pairs using efficacy end points, of which 23 (12.8%) favored the single enantiomer based on primary efficacy end point results. There were 124 RCTs directly comparing drug pairs using safety end points, of which 17 (13.7%) favored the single-enantiomer drug. For 9 of the 15 single-enantiomer drugs (60.0%), no RCTs were identified providing evidence of improved efficacy, based on primary end point results, or safety as compared with their racemic precursors.

CONCLUSIONS AND RELEVANCE

The results of this systematic review suggest that most newly marketed FDA-approved single-enantiomer drugs are infrequently directly compared with their racemic precursors, and when compared, they are uncommonly found to provide improved efficacy or safety, despite their greater costs.

Influence of Levobupivacaine Regional Scalp Block on Hemodynamic Stability, Intra- and Postoperative Opioid Consumption in Supratentorial Craniotomies: A Randomized Controlled Trial

BACKGROUND

The anesthetic management of supratentorial craniotomy (CR) necessitates tight intraoperative hemodynamic control. This type of surgery may also be associated with substantial postoperative pain. We aimed at evaluating the influence of regional scalp block (SB) on hemodynamic stability during the noxious events of supratentorial craniotomies and total intravenous anesthesia, its influence on intraoperative anesthetic agents' consumption, and its effect on postoperative pain control.

METHODS

Sixty patients scheduled for elective CR were prospectively enrolled. Patient, anesthesiologist, and neurosurgeon were blind to the random performance of SB with either levobupivacaine 0.33% (intervention group [group SB], n = 30) or the same volume of saline (control group [group CO], placebo group, n = 30). General anesthesia was induced and maintained using target-controlled infusions of remifentanil and propofol that were adjusted according to hemodynamic parameters and state entropy of the electroencephalogram (SE), respectively. Mean arterial blood pressure (MAP), heart rate (HR), SE, and propofol and remifentanil effect-site concentrations (Ce) were recorded at the time of scalp block performance (Baseline), and 0, 1, 3, and 5 minutes after skull-pin fixation (SP), skin incision (SI), CR, and dura-mater incision (DM). Morphine consumption and postoperative pain intensity (0-10 visual analog scale [VAS]) were recorded 1, 3, 6, 24, and 48 hours after surgery. Propofol and remifentanil overall infusion rates were also recorded. Data were analyzed using 2-tailed Student unpaired t tests, 2-way mixed-design analysis of variance (ANOVA), and Tukey's honestly significant difference (HSD) tests for post hoc comparisons as appropriate.

RESULTS

Demographics and length of anesthetic procedure of group CO and SB were comparable. SP, SI, and CR were associated with a significantly higher MAP in group CO than in group SB, at least at one of the time points of recording surrounding those noxious events. This was not the case at DM. Similarly, HR was significantly higher in group CO than in group SB during SP and SI, at least at 1 of the points of recording, but not during CR and DM. Propofol and remifentanil Ce and overall infusion rates were significantly higher in group CO than in group SB, except for propofol Ce during SP. Postoperative pain VAS and cumulative morphine consumption were significantly higher in group CO than in group SB.

CONCLUSIONS

In supratentorial craniotomies, SB improves hemodynamic control during noxious events and provides adequate and prolonged postoperative pain control as compared to placebo.

A Randomized Comparison of Plasma Levobupivacaine Concentrations Following Thoracic Epidural Analgesia and Subpleural Paravertebral Analgesia in Open Thoracic Surgery

Background: The aim of this study was to compare plasma levobupivacaine concentrations in thoracic epidural and subpleural paravertebral analgesia. Methods: Forty-four patients indicated for open lung resection had an epidural catheter inserted preoperatively or a subpleural catheter surgically. A bolus of 0.25% levobupivacaine at a dosage of 0.5 mg × kg⁻¹ was given after the thoracotomy closure. Plasma levobupivacaine level at 30 min was the primary outcome. Pharmacokinetic modeling was performed subsequently. Secondary outcomes included the quality of analgesia, complications, and patients’mobility. Results: Plasma concentrations were similar 30 min after application—0.389 mg × L⁻¹ in the epidural and 0.318 mg × L⁻¹ in the subpleural group (p = 0.33) and lower in the subpleural group at 120 min (p = 0.03). The areas under the curve but not maximum concentrations were lower in the subpleural group. The time to reach maximum plasma level was similar in both groups—27.6 vs. 24.2 min. No clinical symptoms of local anesthetic toxicity were recorded. Conclusions: Levobupivacaine systemic concentrations were low in both groups without the symptoms of toxicity. This dosage should be safe for postoperative analgesia after thoracotomy.

Successful anesthetic management for total mastectomy in a pregnant woman using general anesthesia combined with continuous erector spinae plane block: a case report

Background

Anesthetic considerations for surgery during pregnancy include the safety of both mother and fetus. We successfully administered anesthesia for total mastectomy to a pregnant woman using general anesthesia combined with continuous erector spinae plane block.

Case presentation

A 41-year-old woman was scheduled to undergo total mastectomy at 18 weeks’ gestation. Hence, we decided to administer general anesthesia combined with continuous erector spinae plane block to minimize physiological stress on both mother and fetus. Continuous erector spinae plane block provided sufficient postoperative analgesia for our patient, completely eliminating the need for additional rescue analgesia during the entire postoperative period.

Conclusions

General anesthesia combined with continuous erector spinae plane block provided adequate analgesia without maternal hypotension in a pregnant woman undergoing total mastectomy.

Cardiovascular tolerance of intravenous bupivacaine in broiler chickens (Gallus gallus domesticus) anesthetized with isoflurane

OBJECTIVE

To determine the median effective dose (ED₅₀) of intravenous (IV) bupivacaine associated with a 50% probability of causing clinically relevant cardiovascular effects [defined as 30% change in heart rate (HR) or mean arterial pressure (MAP)] in chickens anesthetized with isoflurane.

STUDY DESIGN

Randomized up-and-down study.

ANIMALS

A total of 14 Ross-708 broiler chickens (Gallus gallus domesticus) weighing 1.70-2.75 kg.

METHODS

Anesthesia was induced and maintained with isoflurane. Monitoring included the electrocardiogram and invasive arterial pressures. Chickens were administered bupivacaine IV over 2 minutes using a dose based on the response of the previous animal. Dose was decreased when HR and/or MAP in the previous animal increased or decreased ≥30% after bupivacaine administration, or increased when HR or MAP changed <30%. The ED₅₀ was defined as the dose resulting in ≥30% variation in HR or MAP in 50% of the population studied.

RESULTS

The IV ED₅₀ of bupivacaine was 1.94 mg kg^-1 using Dixon's up-and-down method and 1.96 mg kg^-1 by logistic regression.

CONCLUSIONS AND CLINICAL RELEVANCE

These results suggest that 1.33 and 1.96 mg kg^-1 of IV bupivacaine are associated with a respective 1 or 50% probability of a clinically significant change in MAP in isoflurane-anesthetized chickens. Identification of the cardiovascular changes associated with different doses of bupivacaine can be used as the basis for studies of therapeutic applications in the domestic chicken. Further studies are required to determine interspecies variation.

The effects of intra-articular levobupivacain versus levobupivacain plus magnesium sulfate on postoperative analgesia in patients undergoing arthroscopic meniscectomy: A prospective randomized controlled study

Objective

The aim of this study was to compared the effectiveness of intraarticular levobupivacain with levobupivacain and magnesium sulfate.

Methods

In this prospective randomized double blinded study, 96 patients (67 male, 29 female; age range: 18–65 years) with ASA (American Society of Anesthesiologist) score I and II, who had undergone arthroscopic meniscectomy operation, were divided to 3 groups that had postoperative analgesia with intra-articular saline injection (control group), levobupivacain injection (L group) or levobupivacain and magnesium sulfate injection (LM group). Patients were compared with postoperative VAS (Visual Analog Score) score during rest and activity, opioid analgesic need, non-opioid analgesic need and other medication needs.

Results

Postoperative VAS scores during rest and activation at early postoperative period were significantly lower at LM group when compared with L group and lower than control group at all time periods. Opioid analgesic need, non-opioid analgesic need and other medication needs for non-pain symptoms were lower at LM group when compared with L and control groups at all time periods.

Conclusion

Intraarticular magnesium sulfate plus Levobupivacain injection is a safe and effective method for post operative pain management after arthroscopic meniscectomy.

Keywords: Intra-articular injection, Magnesium sulfate, Levobupivacain, Postoperative analgesia, Chondrocyte apoptosis, Pain management, Arthroscopic menisectomy

Level of Evidence

Level I, Therapeutic study

The effect of intra-articular levobupivacaine on shoulder cartilage at different doses-experimental study

BACKGROUND AND OBJECTIVES

In this study it was aimed to examine the histological and morphometric effects on cartilage structure of intra-articular application of levobupivacaine to the shoulder joint.

METHODS

In twenty New Zealand adult male rabbits, 35 shoulders were used for the study and prepared in 5 groups of 7. These groups were defined as Groups L1, L2, L3 and L4 which were right shoulders administered with 0.25% and 0.5% levobupivacaine, Group C which were left shoulders as the control group and Groups S1 and S2 which were left shoulders administered with 0.9% saline. On the 2nd and 15th days the animals were killed, the glenohumeral joints were evaluated macroscopically then cartilage samples were taken. These samples were evaluated with Mankin score, and histomorphometrically by measuring the thickness of the cartilage between the superficial cartilage layer and the tidemark and the thickness of calcified cartilage between the tidemark and the subchondral bone.

RESULTS

Macroscopically, on the 15th day the joint fluid was seen to have reduced in all the groups. After microscopic evaluation, the highest Mankin score (mean: 3.14±2.1/14) was in the L4 group (15th day 0.5% levobupivacaine) and was found to be statistically significant (p<0.05). No statistically significant difference was determined between the other groups.

CONCLUSIONS

Histologically, as the highest Mankin score was in the L4 group, this indicates that in a single intra-articular injection of levobupivacaine a low concentration should be selected.

LEVEL OF EVIDENCE

Level 5, animal study.

[The effect of intra-articular levobupivacaine on shoulder cartilage at different doses-experimental study]

BACKGROUND AND OBJECTIVES

In this study it was aimed to examine the histological and morphometric effects on cartilage structure of intra-articular application of levobupivacaine to the shoulder joint.

METHODS

In twenty New Zealand adult male rabbits, 35 shoulders were used for the study and prepared in 5 groups of 7. These groups were defined as Groups L1, L2, L3 and L4 which were right shoulders administered with 0.25% and 0.5% levobupivacaine, Group C which were left shoulders as the control group and Groups S1 and S2 which were left shoulders administered with 0.9% saline. On the 2nd and 15th days the animals were killed, the glenohumeral joints were evaluated macroscopically then cartilage samples were taken. These samples were evaluated with Mankin score, and histomorphometrically by measuring the thickness of the cartilage between the superficial cartilage layer and the tidemark and the thickness of calcified cartilage between the tidemark and the subchondral bone.

RESULTS

Macroscopically, on the 15th day the joint fluid was seen to have reduced in all the groups. After microscopic evaluation, the highest Mankin score (mean: 3.14±2.1/14) was in the L4 group (15th day 0.5% levobupivacaine) and was found to be statistically significant (p<0.05). No statistically significant difference was determined between the other groups.

CONCLUSIONS

Histologically, as the highest Mankin score was in the L4 group, this indicates that in a single intra-articular injection of levobupivacaine a low concentration should be selected.

LEVEL OF EVIDENCE

Level 5, animal study.

A comparative study of dexmedetomidine and fentanyl as adjuvants to levobupivacaine for caudal analgesia in children undergoing lower limb orthopedic surgery

Background:

Levobupivacaine is an effective local anesthetic agent with less systemic toxicity than racemic bupivacaine, but it has short postoperative analgesic duration. Dexmedetomidine and fentanyl are promising adjuncts to provide excellent and prolonged postoperative caudal analgesia. This study compared the effects of caudal levobupivacaine plus dexmedetomidine and levobupivacaine plus fentanyl for postoperative analgesia and sedation in children undergoing lower limb orthopedic surgery.

Patients and Methods:

Ninety children, whose age ranged from 1 to 7 years, American Society of Anesthesiologists I-II, undergoing orthopedic lower limb surgery under general anesthesia received caudal block for postoperative analgesia. The children were randomly allocated into three groups: Group L (control) received 0.75 ml/kg levobupivacaine 0.25% diluted in saline; Group LD received 0.75 ml/kg levobupivacaine 0.25% with dexmedetomidine 1 μg/kg; and Group LF received 0.75 ml/kg levobupivacaine 0.25% with fentanyl 1 μg/kg. Following the administration of the drugs; hemodynamic variables, the total anesthesia time, sedation score, Face, Legs, Activity, Cry, Consolability score, duration of analgesia, and side effects were recorded.

Results:

Demographically, all the groups were comparable, both the baseline and the intraoperative hemodynamic profile were similar in all groups. The mean duration of analgesia and the mean sedation score in the Group LD were significantly greater as compared to both the other groups.

Conclusion:

Dexmedetomidine may be a better additive to levobupivacaine than fentanyl for caudal postoperative analgesia, arousable sedation with comparable hemodynamic and side effect profile in children.

Postarthroscopy analgesia using intraarticular levobupivacaine and intravenous dexketoprofen trometamol

PURPOSE

The aim of this prospective study was to determine the efficacy of intraarticular levobupivacaine with and without intravenous dexketoprofen trometamol for postarthroscopy analgesia.

METHODS

Sixty patients who underwent arthroscopic knee surgery were randomly assigned to three treatment groups. When the surgical procedure was completed, patients received the following treatments: group I (n = 20) patients received 20 mL intraarticular normal saline and 2 mL intravenous dexketoprofen trometamol (50 mg); group II (n = 20) patients received 20 mL intraarticular 0.5 % levobupivacaine (100 mg) and 2 mL intravenous normal saline; and group III (n = 20) patients received 20 mL intraarticular 0.5 % levobupivacaine (100 mg) and 2 mL intravenous dexketoprofen trometamol (50 mg). The visual analogue scale (VAS) was used, and the total analgesic consumption was assessed at 1, 2, 4, 6, 12, and 24 h post-operatively.

RESULTS

The VAS scores at 1, 2, 4, 6, 12, and 24 h post-operatively were significantly increased in group I and group II compared with group III (p < 0.05). The average VAS score during the first 24 h post-operatively was significantly lower in group III than in group I and group II (p < 0.001). Total meperidine consumption was significantly lower in group III than in groups I and II (p < 0.001).

CONCLUSION

Intraarticular levobupivacaine with adjuvant intravenous dexketoprofen trometamol administration provided better pain relief and less analgesic requirement after arthroscopic knee surgery during the first 24 h than that induced by dexketoprofen alone or levobupivacaine intraarticular alone.

LEVEL OF EVIDENCE

II.

A randomized clinical study comparing spinal anesthesia with isobaric levobupivacaine with fentanyl and hyperbaric bupivacaine with fentanyl in elective cesarean sections

BACKGROUND

To date, racemic bupivacaine is the most popular local anesthetic for spinal anesthesia in parturients undergoing elective cesarean delivery. With the introduction of levobupivacaine as pure S (-) enantiomer of bupivacaine which offers advantages of lower cardiotoxicity and neurotoxicity and shorter motor block duration, its use has widely increased in India. However, very few studies have been conducted about its efficacy in obstetric anesthesia. Thus, this study was undertaken to compare the sensorial, motor block levels, and side-effects of equal doses of hyperbaric bupivacaine and levobupivacaine with intrathecal fentanyl addition in elective cesarean cases.

MATERIALS AND METHODS

After approval of College Ethical Committee, 30 parturient with American Society of Anesthesiologists I-II undergoing elective cesarean section were enrolled for study with their informed consent. They were randomly divided equally to either Group BF receiving 10 mg (2 ml) hyperbaric bupivacaine and 25 mcg (0.5 ml) fentanyl, or Group LF receiving 10 mg (2 ml) isobaric levobupivacaine and 25 mcg (0.5 ml) fentanyl. Sensory and motor block characteristics of the groups were assessed with pinprick, cold swab, and Bromage scale; observed hemodynamic changes and side-effects were recorded. Effects on the neonate were observed by APGAR score at 1 and 5 min and umbilical cord blood gas analysis.

RESULTS

Hemodynamic parameters like mean arterial pressure of Group BF were found to be lower. Group BF exhibited maximum motor block level whereas in Group LF, max sensorial block level and postoperative visual analog scale scores were higher. Umbilical blood gas pCO2 was slightly higher, and pO2 was marginally lower in Group BF. Onset of motor block time, time to max motor block, time to T10 sensorial block, reversal of two dermatome, the first analgesic need were similar in both groups.

CONCLUSION

Intrathecal isobaric levobupivacaine-fentanyl combination is a good alternative to hyperbaric bupivacaine-fentanyl combination in cesarean surgery as it is less effective in motor block, it maintains hemodynamic stability at higher sensorial block levels.

Voltage-dependent blockade by bupivacaine of cardiac sodium channels expressed in Xenopus oocytes

Bupivacaine ranks as the most potent and efficient drug among class I local anesthetics, but its high potential for toxic reactions severely limits its clinical use. Although bupivacaine-induced toxicity is mainly caused by substantial blockade of voltage-gated sodium channels (VGSCs), how these hydrophobic molecules interact with the receptor sites to which they bind remains unclear. Nav1.5 is the dominant isoform of VGSCs expressed in cardiac myocytes, and its dysfunction may be the cause of bupivacaine-triggered arrhythmia. Here, we investigated the effect of bupivacaine on Nav1.5 within the clinical concentration range. The electrophysiological measurements on Nav1.5 expressed in Xenopus oocytes showed that bupivacaine induced a voltage- and concentration-dependent blockade on the peak of I Na and the half-maximal inhibitory dose was 4.51 μmol/L. Consistent with other local anesthetics, bupivacaine also induced a use-dependent blockade on Nav1.5 currents. The underlying mechanisms of this blockade may contribute to the fact that bupivacaine not only dose-dependently affected the gating kinetics of Nav1.5 but also accelerated the development of its open-state slow inactivation. These results extend our knowledge of the action of bupivacaine on cardiac sodium channels, and therefore contribute to the safer and more efficient clinical use of bupivacaine.

Spinal anesthesia for knee arthroscopy using isobaric bupivacaine and levobupivacaine: anesthetic and neuroophthalmological assessment

INTRODUCTION

The aim of the study was to compare the sensory, motor, and neuroophthalmological effects of isobaric levobupivacaine and bupivacaine when intrathecally administered.

MATERIALS AND METHODS

A prospective, double-blind, randomized study with 60 ASA grade I-II patients aged 18-65 years awaiting knee arthroscopy under spinal anesthesia. Patients received 12.5 mg of isobaric bupivacaine or levobupivacaine. Several features were recorded.

RESULTS

No significant intergroup differences were observed for ASA classification, time to micturate, demographic data, surgery duration, and patient/surgeon satisfaction. Similar hemodynamic parameters and sensory/motor blockade duration were found for both groups. There were no neuroophthalmological effects in either group. Sensory (P = 0.018) and motor blockade onset (P = 0.003) was faster in the bupivacaine group. T6 (T2-T12) and T3 (T2-T12) were the highest sensory block levels for the levobupivacaine and bupivacaine groups, respectively (P = 0.008). It took less time to regain maximum motor blockade in the bupivacaine group (P = 0.014), and the levobupivacaine group required use of analgesia earlier (P = 0.025).

CONCLUSIONS

Isobaric bupivacaine and levobupivacaine are analogous and well-tolerated anesthetics for knee arthroscopy. However, for bupivacaine, sensory and motor blockade onset was faster, and greater sensory blockade with a longer postoperative painless period was achieved.

Comparative study related to cardiovascular safety between bupivacaine (S75-R25) and ropivacaine in brachial plexus block

BACKGROUND AND OBJECTIVES

Bupivacaine is a first choice for regional anesthesia considering its effectiveness, long duration and less motor blockade. Bupivacaine (S75-R25) is a mixture of optical isomers containing 75% levobupivacaine (S-) and 25% dextrobupivacaine (R+) created by a Brazilian pharmaceutical company. This investigation compared cardiac safety and efficacy of bupivacaine S75-R25 with vasoconstrictor and ropivacaine for brachial plexus blockade.

METHODS

Patients were randomized to receive brachial plexus anesthesia with either bupivacaine S75-R25 with epinephrine 1:200,000 (bupi) or ropivacaine (ropi), both at 0.50%, in 30 mL solution. We registered a continuous Holter ECG throughout the procedure, as well as the Lovett scale of force in addition to monitoring (heart rate, pulse oximetry and non-invasive blood pressure). The incidence of adverse events was compared with the chi-square or Fisher test.

RESULTS

We allocated forty-four patients into two groups. They did not show any difference related to age, weight or height, gender, as well as for surgical duration. Supraventricular arrhythmias were not different before or after the plexus blockade, independent of the local anesthetic chosen. Loss of sensitivity was faster for the bupivacaine group (23.1 ± 11.7 min) compared to the ropivacaine one (26.8 ± 11.5 min), though not significant (p = 0.205, Student t). There was a reduction in the cardiac rate, observed during the twenty-four-hour Holter monitoring.

CONCLUSIONS

This study showed similar efficacy between bupivacaine S75-R25 for brachial plexus blockade and ropivacaine, with similar incidences of supraventricular arrhythmias.

Comparação da latência anestésica de Articaína, Lidocaína, Levobupivacaína e Ropivacaína através de 'Pulp Tester'

INTRODUÇÃO: Um conhecimento profundo dos anestésicos odontológicos, como o tempo de latência da droga, pode assegurar o êxito do controle da dor no trans e no pós-operatório. OBJETIVO: Comparar a latência entre quatro soluções anestésicas, ou seja, o tempo entre o início da deposição do anestésico local e o momento em que seus efeitos tornam-se perceptíveis. Entretanto, isso não está relacionado com o êxito do controle da dor no trans e no pós-operatório (profundidade da anestesia). MATERIAL E MÉTODO: Foi realizado um estudo duplo cego, cruzado e randomizado, com 30 pacientes voluntários submetidos a quatro procedimentos em intervalos de uma semana, a partir de bloqueio do alveolar superior posterior. No segundo molar a ser tratado, foi utilizado o 'pulp tester' em intervalos de 2 minutos, considerando a insensibilidade da polpa quando da ausência de resposta após dois testes consecutivos de 80muV, chegando ao máximo de 10 minutos e determinando, assim, o período de latência do anestésico. Os dados foram submetidos aos testes T-student, de Friedman e de Kruskal-Wallis (p<0,05). RESULTADO: Não houve diferenças estatisticamente significativas (p=0,8327) entre as soluções anestésicas. Para todas estas, a mediana foi 2 minutos. Não houve, ainda, diferenças significantes entre os gêneros em relação à idade (p=0,4545), bem como entre os valores, quando se tentou observar a influência do gênero nos valores de latência (p=0,6754). CONCLUSÃO: Sendo os tempos médios de latência idênticos, a escolha da droga dependerá da duração do procedimento cirúrgico-odontológico a se realizar, além da necessidade ou não de analgesia pós-operatória.

Liposomal extended-release bupivacaine for postsurgical analgesia

When physicians consider which analgesia to use postsurgery, the primary goal is to relieve pain with minimal adverse side effects. Bupivacaine, a commonly used analgesic, has been formulated into an aqueous suspension of multivesicular liposomes that provide long-lasting analgesia for up to 72 hours, while avoiding the adverse side effects of opioids. The increased efficacy of liposomal extended-release bupivacaine, compared to bupivacaine hydrochloride, has promoted its usage in a variety of surgeries including hemorrhoidectomy, bunionectomy, inguinal hernia repair, total knee arthroplasty, and augmentation mammoplasty. However, like other bupivacaine formulations, the liposomal extended-release bupivacaine does have some side effects. In this brief review, we provide an update of the current knowledge in the use of bupivacaine for postsurgical analgesia.

Comparative study related to cardiovascular safety between bupivacaine (S75-R25) and ropivacaine in brachial plexus block

BACKGROUND AND OBJECTIVES

Bupivacaine is a fi rst choice for regional anesthesia considering its effectiveness, long duration and less motor blockade. Bupivacaine (S75-R25) is a mixture of optical isomers containing 75% levobupivacaine (S-) and 25% dextrobupivacaine (R+) created by a Brazilian pharmaceutical company. This investigation compared cardiac safety and efficacy of bupivacaine S75-R25 with vasoconstrictor and ropivacaine for brachial plexus blockade.

METHODS

Patients were randomized to receive brachial plexus anesthesia with either bupivacaine S75-R25 with epinephrine 1:200,000 (bupi) or ropivacaine (ropi), both at 0.50%, in 30 mL solution.We registered a continuous Holter ECG throughout the procedure, as well as the Lovett scale of force in addition to monitoring (heart rate, pulse oximetry and non-invasive blood pressure). The incidence of adverse events was compared with the chi-square or Fisher test.

RESULTS

We allocated forty-four patients into two groups. They did not show any difference related to age, weight or height, gender, as well as for surgical duration. Supraventricular arrhythmias were not different before or after the plexus blockade, independent of the local anestheticchosen. Loss of sensitivity was faster for the bupivacaine group (23.1 ± 11.7 min) compared to the ropivacaine one (26.8 ± 11.5 min), though not significant (p = 0.205, Student t). There was a reduction in the cardiac rate, observed during the twenty-four-hour Holter monitoring.

CONCLUSIONS

This study showed similar efficacy between bupivacaine S75-R25 for brachial plexus blockade and ropivacaine, with similar incidences of supraventricular arrhythmias.

A comparison of levobupivacaine and levobupivacaine-tramadol combination in bilateral infraorbital nerve block for postoperative analgesia after nasal surgery

BACKGROUND

Our aim in this study was to investigate the effect of levobupivacaine and a levobupivacaine + tramadol combination on postoperative analgesia in intraoperative nerve block under standard general anesthetic.

METHODS

Forty-five patients undergoing outpatient nasal surgery under general anesthesia were randomized into 3 groups. Group L: 0.25% levobupivacaine, group T: 0.25% levobupivacaine and 50 mg tramadol, group S: normal saline solution; 2 mL of each being injected into the infraorbital foramen. Intraoperative hemodynamic changes were recorded. Verbal numeric rating scale (NRS) values were checked at 30 minutes and 1, 2, 8, and 12 hours postoperatively, and the need for rescue analgesic treatment in the first 12 hours of all patients was recorded. Also antiemetic drug requirement and side effects (nausea, edema, erythema, hematoma, and sedation) were recorded.

RESULTS

At 30 minutes and 1 hour postoperatively, NRS pain scores were lower in group T than in group S (P < 0.0001, P = 0.01, respectively). NRS pain score was lower in group T compared with group L at 1 hour postoperatively (P = 0.01). Effective analgesia time (sec) in the control group (142.67 ± 77.31) was shorter than levobupivacaine (240 ± 96.39) and levobupivacaine added to tramadol groups (277 ± 11.60) (P < 0.05). Additional analgesic requirement in the control group was higher than the other 2 groups in early postoperative period (P < 0.05).

CONCLUSIONS

Bilateral infraorbital nerve block with 0.25% levobupivacaine is an effective, reliable, and simple technique in the treatment of postoperative pain in nasal surgery. In addition, the addition of tramadol as an adjuvant to local anesthetics in this technique is safe.

Effect of intra-articular injection of levobupivacaine on articular cartilage and synovium in rats

OBJECTIVE

Intra-articular local anesthetics are often used for prevention of pain after arthroscopic knee surgery. However, the effect of local anesthetics other than bupivacaine on articular cartilage and synovium has not been studied. Also, complications associated with the injection of intra-articular bupivacaine have appeared in the literature. The aim of this study was to evaluate the effects of levobupivacaine on the articular cartilage and the synovium in rats.

METHODS

Under aseptic conditions 0.25 ml (5 mg/ml) of levobupivacaine was injected into the right knee joint while 0.25 ml of saline was simultaneously injected into the left knee joint of 20 adult Sprague-Dawley rats. The purpose of saline injections was to serve as a control group. Groups of five rats were killed on days 1, 7, 14 and 21 after administration of injections. The knee joint samples were evaluated for the presence of inflammation in the articular and periarticular tissues and the synovium.

RESULTS

There were no significant differences between the levobupivacaine and control groups with respect to inflammation in the articular and periarticular tissues and the synovium.

CONCLUSIONS

Although more studies are needed before final recommendations can be made, by evaluating the results obtained from this study, the clinical use of intra-articular levobupivacaine can be recommended for arthroscopic knee surgery.

Comparison of efficacy of intraarticular application of magnesium, levobupivacaine and lornoxicam with placebo in arthroscopic surgery

PURPOSE

Arthroscopic knee surgery is done in outpatient settings; however, postoperative pain is a major barrier for discharge and limits early rehabilitation. The efficacy of intraarticular application of magnesium sulphate, levobupivacaine and lornoxicam, with placebo on postoperative pain after arthroscopic meniscectomy was evaluated.

METHODS

One hundred and twenty ASA status I-II patients undergoing elective arthroscopic meniscectomy were included in this randomized, single blind, prospective study. Group-M (GM) patients had intraarticular 500 mg of magnesium sulphate in 20 ml saline; group-P (GP) patients had intraarticular 20 ml saline; group-LB (GLB) patients had 100 mg levobupivacaine in 20 ml (0.5%); group-L (GL) patients had intraarticular 8 mg of lornoxicam in 20 ml saline before tourniquet deflation. Postoperative analgesia was maintained by iv tramadol PCA 0.3 mg kg(-1) bolus dose and 5 min lockout time during the first 4 h and later with paracetamol 500 mg. The NRS values at rest and at exercise and analgesic consumptions were evaluated at the end of the first, second and 4th hours and at the 12th, 24th and 48th hours by an anaesthesiologist who was blind to the solutions administered.

RESULTS

All study groups provided analgesia when compared with GP. The first request of oral analgesic time was shorter in GP. Analgesic consumptions of GP were higher than other groups. Pain scores during 1, 2 and 4 h postoperatively were lower in all study groups than the GP.

CONCLUSION

Administration of all the drugs provided better analgesia than placebo and the most effective one was lornoxicam.

Comparison of two different doses of intrathecal levobupivacaine for transurethral endoscopic surgery

OBJECTIVE

To evaluate the effects of two different spinal isobaric levobupivacaine doses on spinal anesthesia characteristics and to find the minimum effective dose for surgery in patients undergoing transurethral resection (TUR) surgery.

MATERIALS AND METHODS

Fifty male patients undergoing TUR surgery were included in the study and were randomized into two equal groups: Group LB10 (n=25): 10 mg 0.5% isobaric levobupivacaine (2 ml) and Group LB15 (n=25): 15 mg 0.75% isobaric levobupivacaine (2 ml). Spinal anesthesia was administered via a 25G Quincke spinal needle through the L3-4 intervertebral space. Sensorial block levels were evaluated using the 'pin-prick test', and motor block levels were evaluated using the 'Bromage scale'. The sensorial and motor block characteristics of patients during intraoperative and postoperative periods and recovery time from spinal anesthesia were evaluated.

RESULTS

In three cases in the Group LB10, sensorial block did not reach the T10 level. Complete motor block (Bromage=3) did not occur in eight cases in the Group LB10 and in five cases in the Group LB15. The highest sensorial dermatomal level detected was higher in Group LB15. In Group LB15, sensorial block initial time and the time of complete motor block occurrence were significantly shorter than Group LB10. Hypotension was observed in one case in Group LB15. No significant difference between groups was detected in two segments of regression times: the time to S2 regression and complete sensorial block regression time. Complete motor block regression time was significantly longer in Group LB15 than in Group LB10 (p<0.01).

CONCLUSION

Our findings showed that the minimum effective spinal isobaric levobupivacaine dose was 10 mg for TUR surgery.

A comparison of low dose hyperbaric levobupivacaine and hypobaric levobupivacaine in unilateral spinal anaesthesia

The aim of this study was to compare the clinical effects and characteristics of hyperbaric and hypobaric levobupivacaine for unilateral spinal anaesthesia. Sixty patients were randomly allocated into two groups to receive either 7.5 mg (1.5 ml) hyperbaric levobupivacaine 0.5% or 7.5 mg (4 ml) hypobaric levobupivacaine 0.1875% for elective arthroscopic surgery of the knee under spinal anaesthesia. The level and duration of sensory block, intensity and duration of motor block were recorded. Unilateral sensory block was observed in 27 patients (90%) in the hyperbaric group and 24 patients (80%) in the hypobaric group in the lateral position. After 15 minutes, patients were turned to supine to redistribute the spinal block toward the non-operative side, but spinal anaesthesia was still unilateral in 18 patients (60%) in the hyperbaric group and 10 patients (33%) in the hypobaric group (P = 0.038). Time to readiness for home discharge and complete recovery of sensory block were similar in both groups. In the hyperbaric group, the motor block scores were higher on the operative side during first 10 minutes than they were in the hypobaric group (P < 0.002). Motor block regression was faster in the hyperbaric group (P = 0.01). Hyperbaric and hypobaric levobupivacaine both provided satisfactory unilateral spinal anaesthesia with good haemodynamic stability for arthroscopic surgery, but with more frequent unilateral spinal anaesthesia in the hyperbaric group.

Long-acting local anesthetics and perioperative pain management

Although the use of long-acting local anesthetics has become a useful therapeutic approach for managing peri- and postoperative pain, recent evidence reveals unexpected outcomes. This article reviews the clinical use of long-acting local anesthetics, presents current clinical research findings, and makes recommendations for their use.

Does preincisional injection of levobupivacaine with epinephrine have any benefits for children undergoing tonsillectomy? An intraindividual evaluation

OBJECTIVE

To evaluate the effects of peritonsillar injection of levobupivacaine with epinephrine in children undergoing adenotonsillectomy, through an intraindividual study.

PATIENTS AND METHODS

20 children (age 6-13 years) undergoing elective tonsillectomy with or without adenoidectomy were enrolled in this prospective, randomized, intraindividual trial. After entubation and just prior to incision, 3 ml of 0.25% levobupivacaine with epinephrine was injected into one peritonsillar region while 0.9% saline was being used for the contralateral side. Amount of intraoperative blood loss, duration of tonsillectomy, postoperative pain, otalgia and hemorrhage were assessed for each side separately. Visual analog scale was used for postoperative pain assessment. Heart rate and mean arterial pressure during and after operation were also observed. The follow-up period after surgery was 10 days.

RESULTS

Median visual analog scale values for the levobupivacaine with epinephrine injected side was significantly lower than the saline injected side, during the first postoperative 16h (p<0.05). There were also significant differences between the intraoperative blood losses of the two sides (p<0.05). However; no significant differences were observed with respect to duration of surgery, postoperative otalgia and hemorrhage (p>0.05).

CONCLUSION

Preincisional injection of levobupivacaine with epinephrine decreases early postoperative pain and intraoperative blood loss as well.

The acute toxicity of local anesthetics

IMPORTANCE OF THE FIELD

Systemic toxicity, usually from overdose or intravascular dose, is feared because it mainly affects the heart and brain, and may be acutely life-threatening.

AREAS COVERED IN THIS REVIEW

Pharmacological studies of local anesthetic toxicity have largely been reviewed primarily relating to the evaluation of ropivacaine and levobupivacaine during the past decade. This review/opinion focuses more on the principles and concepts underlying the main models used, from chemical pharmacological and pharmacokinetic perspectives.

WHAT THE READER WILL GAIN

Research models required to produce pivotal toxicity data are discussed. The potencies for neural blockade and systemic toxicity are associated across virtually all models, with some deviations through molecular stereochemistry. These models show that all local anesthetics can produce direct cardiovascular system toxicity and CNS excitotoxicity that may further affect the cardiovascular system response. Whereas the longer-acting local anesthetics are more likely to cause cardiac death by malignant arrhythmias, the shorter-acting agents are more likely to cause cardiac contraction failure. In most models, equi-anesthetic doses of ropivacaine and levobupivacaine are less likely to produce serious toxicity than bupivacaine.

TAKE HOME MESSAGE

Of the various models, this reviewer favors a whole-body large animal preparation because of the comprehensive data collection possible. The conscious sheep preparation has contributed more than any other, and may be regarded as the de facto 'standard' experimental model for concurrent study of local anesthetic toxicity ± pharmacokinetics, using experimental designs that can reproduce the toxicity seen in clinical accidents.

Safety of amide local anesthetics: new trends

IMPORTANCE OF THE FIELD

Local anesthetics have become one of the most common drugs used in daily practice worldwide. Neurologic and cardiovascular events are the most frequent adverse reactions related to local anesthetics use. Recently, new trends have been developed on this topic.

AREAS COVERED IN THIS REVIEW

We performed an overview of the data available so far on local anesthetics adverse reactions. Relevant literature was identified using PubMed search of articles published up to November 2009, including experimental studies, case reports or clinical studies when available. Search terms included: 'local anaesthetics', 'adverse drug reaction', 'pharmacovigilance' and 'complication'.

WHAT THE READER WILL GAIN

Neurologic, cardiovascular and allergic reactions remain the most frequent adverse drug reactions related to local anesthetics in the literature. Studies based on pharmacovigilance systems have highlighted the frequency of adverse reactions little known until now, such as failure of block. Lipid emulsions are included into algorithm for cardiac resuscitation. Recent studies have demonstrated the myotoxicity and chondrotoxic effects of long-acting local anesthetics.

TAKE HOME MESSAGE

Physicians must keep in mind all these adverse reactions to better prevent their occurrence and give the most appropriate treatment.

Regional Anaesthesia for Bilateral Upper Limb Surgery: A Review of Challenges and Solutions

Regional anaesthesia for bilateral upper limb surgery can be challenging, yet surgeons are becoming increasingly interested in performing bilateral procedures at the same operation. Anaesthetists have traditionally avoided bilateral brachial plexus block due to concerns about local anaesthetic toxicity, phrenic nerve block and pneumothorax. We discuss these three concerns and review whether advances in ultrasound guidance and nerve catheter techniques should make us reconsider our options. A search of Medline and EMBASE from 1966 to January 2009 was conducted using multiple search terms to identify techniques of providing anaesthesia or analgesia for bilateral upper limb surgery and potential side-effects. Ultrasound imaging and nerve catheter techniques have led to a reduction in dose requirements for effective blocks without side-effects. Effective regional anaesthesia can be performed for bilateral surgery while remaining within recommended safe dose limits. Spacing blocks apart in time can further reduce potential toxicity issues, such that peak absorption rates for each block do not coincide. Since phrenic nerve block remains an issue even with low doses of local anaesthesia, bilateral interscalene blocks are still not recommended. Peripheral nerve blocks have excellent safety profiles and are ideal for ultrasound guidance. Regional anaesthesia can be a suitable option for bilateral upper limb surgery.

Injectable corticosteroid and local anesthetic preparations: a review for radiologists

Corticosteroids and local anesthetics are some of the most commonly administered medications in radiology departments. These medications have marked variability in their formulations, which may increase their adverse event profile for specific procedures. In particular, certain corticosteroid preparations are associated with adverse central nervous system (CNS) sequelae. This is most likely due to distal embolization by particulate formulations. Nonparticulate steroid formulations are not associated with such events. Local anesthetics have severe CNS and cardiac adverse effects if injected intravascularly and have recently been associated with intraarticular chondrolysis if used in large doses. This review discusses these medications with particular emphasis on their established and postulated adverse effects. The administering radiologist should be aware of these potential effects and how best to reduce their occurrence.