Safety, Pharmacokinetics/Pharmacodynamics, and Absolute Bioavailability of Dexmedetomidine Hydrochloride Nasal Spray in Healthy Subjects: A Randomized, Parallel, Escalating Dose Study

Dexmedetomidine Nasal Spray on Emergence Agitation After Ear, Nose, and Throat Surgery: Protocol for a Randomized, Double-Blind, Controlled Trial

Background

Emergence agitation (EA) is a state of psychomotor hyperactivity following general anesthesia and is associated with postoperative complications. Patients undergoing ear, nose, and throat (ENT) surgery are at a high risk for EA. We aim to assess whether preoperative dexmedetomidine nasal spray reduces the occurrence of EA for patients undergoing ENT surgery.

Methods

This is a protocol for a randomized, double-blind, controlled trial that will include 160 adults scheduled for ENT surgery. Patients will be randomly assigned, in a 1:1 ratio, to receive dexmedetomidine nasal spray (100 μg) or a same volume of normal saline approximately 30 min before general anesthesia induction. The primary endpoint is the incidence of EA, defined as a Riker sedation agitation scale (RSAS) score ≥5 from discontinuation of sevoflurane until 5 min after tracheal extubation. Secondary endpoints include (1) the maximal RSAS score during emergence; (2) the incidence of agitation in the postoperative care unit (PACU); (3) pain at rest and while coughing in the PACU and at 24 h postoperatively; (4) postoperative sleep disturbance on the first night after surgery; (5) anxiety within 24 h postoperatively; and (6) postoperative delirium during the first 24 h after surgery. All analyses will be performed on a modified intention-to-treat basis. For the primary endpoint, subgroup analysis will be conducted on sex, age, and type of surgery.

Discussion

We expect that preoperative dexmedetomidine nasal spray would reduce the incidence of EA after ENT surgery. Our results offer clinical evidence for improving anesthetic care for patients undergoing ENT surgery.

Trial Registration

Chinese Clinical Trial Registry (Identifier: ChiCTR2400086731).

Absorption pharmacokinetics and feasibility of intranasal dexmedetomidine in patients under general anaesthesia

BACKGROUND

The use of intranasal dexmedetomidine is hampered by a limited understanding of its absorption pharmacokinetics.

METHODS

We examined the pharmacokinetics and feasibility of intranasal dexmedetomidine administered in the supine position to adult patients undergoing general anaesthesia. Twenty-eight patients between 35 and 80 years of age, ASA 1-3 and weight between 50 and 100 kg, who underwent elective unilateral total hip or knee arthroplasty under general anaesthesia were recruited. All patients received 100 μg of intranasal dexmedetomidine after anaesthesia induction. Six venous blood samples (at 0, 5, 15, 45, 60, 240 min timepoints from dexmedetomidine administration) were collected from each patient and dexmedetomidine plasma concentrations were measured. Concentration-time profiles after nasal administration were pooled with earlier data from a population analysis of intravenous dexmedetomidine (n = 202) in order to estimate absorption parameters using nonlinear mixed effects. Peak concentration (CMAX) and time (TMAX) were estimated using simulation (n = 1000) with parameter estimates and their associated variability.

RESULTS

There were 28 adult patients with a mean (SD) age of 66 (8) years and weight of 83 (10) kg. The mean weight-adjusted dose of dexmedetomidine was 1.22 (0.15) μg kg-1. CMAX 0.273 μg L-1 was achieved at 98 min after intranasal administration (TMAX). The relative bioavailability of dexmedetomidine was 80% (95% CI 75-91%). The absorption half-time (TABS = 120 min; 95% CI 90-147 min) was slower than that in previous pharmacokinetic studies on adult patients. Perioperative haemodynamics of all patients remained stable.

CONCLUSIONS

Administration of intranasal dexmedetomidine in the supine position during general anaesthesia is feasible with good bioavailability. This administration method has slower absorption when compared to awake patients in upright position, with consequent concentrations attained after TMAX for several hours.

Safety and efficacy of a novel dexmedetomidine nasal spray for pre-anesthetic sedation in children: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Off-label intranasal administration of injectable dexmedetomidine has been widely applied in the pediatric sedation setting. However, the development of an improved drug delivery system that is easy to use is needed. We developed a novel dexmedetomidine nasal spray that can be administered directly without dilution or configuration for pediatric pre-anesthetic sedation. This nasal spray has a fixed dose and is stable during storage. To the best of our knowledge, this is the first licensed nasal spray preparation of dexmedetomidine worldwide.

OBJECTIVE

To evaluate the pre-anesthetic sedation efficacy and safety of the novel dexmedetomidine nasal spray in children.

METHODS

The study was conducted at 11 sites in China between 24 November 2021 and 20 May 2022 and was registered in ClinicalTrials.gov (NCT05111431, first registration date: 20/10/2021). Subjects (n = 159) between 2 and 6 years old who were to undergo elective surgery were randomized to the dexmedetomidine group (n = 107) or the placebo group (n = 52) in a 2:1 ratio. The dosage was 30 µg or 50 µg based on the stratified body weight. The primary outcome measure was the proportion of subjects who achieved the desired child-parent separation and Ramsay scale ≥ 3 within 45 min of administration. Safety was monitored via the assessments of adverse events, blood pressure, heart rate, respiratory rate and blood oxygen saturation.

RESULTS

The proportion of subjects achieving desired parental separation and Ramsay scale ≥ 3 within 45 min was significantly higher in the dexmedetomidine group (94.4%) vs the placebo group (32.0%) (P < 0.0001). As compared with placebo, dexmedetomidine treatment led to more subjects achieving Ramsay scale ≥ 3 or UMSS ≥ 2, and shorter time to reach desired parental separation, Ramsay scale ≥ 3 and UMSS ≥ 2 (all P < 0.0001). Adverse events were reported in 90.7% and 84.0% of subjects in the dexmedetomidine and placebo groups, respectively, and all the events were mild or moderate in severity.

CONCLUSIONS

This novel dexmedetomidine nasal spray presented effective pre-anesthetic sedation in children with a tolerable safety profile.

Dexmedetomidine nasal administration improves perioperative sleep quality and neurocognitive deficits in elderly patients undergoing general anesthesia

OBJECTIVE

To investigate the improvement of perioperative sleep quality and neurocognitive impairment in elderly patients under general anesthesia by nasal administration of dexmedetomidine.

METHODS

One hundred and twenty patients admitted to our hospital for various laparoscopic elective gynecological surgeries lasting more than 1 h under general anesthesia from July 2021 to March 2023 were selected. All subjects were divided into 3 groups according to the random number table method. From 21:00 to 21:30 every night from one day before to 5 days after surgery, group A was given alprazolam 0.4 mg orally; group B was given dexmedetomidine 1.5ug/kg nasal drip; group C was given saline nasal drip. All subjects were observed for general information, sleep quality, postoperative cognitive function, anxiety status, sleep quality, adverse effects and complication occurrence.

RESULTS

The difference in general information between the three groups was not statistically significant, P > 0.05; the sleep quality scores of the three groups on admission were not statistically significant, P > 0.05. At the Preoperative 1d, postoperative 1d, 3d and 5d, the RCSQ scores of the subjects in group A and group B were higher than those in groups C, and with the postoperative RCSQ scores of subjects in group B were higher as the time increased; the assessment of anxiety status in the three groups 1d before surgery was not statistically significant, P > 0.05. The cognitive function scores of subjects in the three groups were not statistically significant in the preoperative 1d, P > 0.05. The postoperative 1d (24.63 ± 2.23), 3d (25.83 ± 2.53), and 5d (26.15 ± 2.01) scores of the subjects in group B were higher than those in groups A and C (P < 0.05), and the subjects in group B had better recovery of postoperative cognitive function with increasing time; the occurrence of postoperative delirium (POD) in group B (12.5%) were lower on postoperative 5d than those in groups A (37.5%) and C (32.5%) (P < 0.05). There was no statistical significance in the evaluation of anxiety state of the three groups on the first day before operation (P > 0.05). The scores in group B were lower than those in group C on the postoperative 1d, 3d, 5 d (P < 0.05). The overall incidence of adverse reactions and complications in subjects in group B was 17.5% significantly lower than that in groups A and C (P < 0.05).

CONCLUSION

Dexmedetomidine can effectively improve the sleep disorder of elderly general anesthesia patients, reduce the damage to their neurocognitive function and the occurrence of POD, effectively reduce the anxiety of patients and the occurrence of adverse reactions and complications, and has better sedative, improve postoperative cognitive function and anti-anxiety effects, with a high drug safety, worthy of clinical application and promotion.

Clinical Analysis of Intranasal Dexmedetomidine Combined With Midazolam in Pediatric Cranial Magnetic Resonance Examinations

PURPOSE

To observe the efficacy and safety of intranasal dexmedetomidine combined with midazolam in cranial magnetic resonance imaging of children.

DESIGN

A prospective, observational, single-arm, one-center study.

METHODS

A total of 474 children were scheduled for cranial 3.0 T MRI at the first time. All patients were initially given 3 mcg/kg dexmedetomidine combined with 0.15 mg/kg midazolam. The one-time success rate, vital signs before and after treatment, onset time, recovery time, and incidence of adverse reactions were recorded.

FINDINGS

The one-time success rate was 78.1%. There were significant differences in respiration, heart rate, and blood oxygen saturation before and after treatment (P < .001). The onset time was 10 (8-15) minutes. The average recovery time was 2.58 ± 1.10 hours. Only 1.27% (6 cases) of adverse reactions were observed, including bradycardia (3 cases, 0.6%), tachycardia (1 case, 0.2%), and startle (2 cases, 0.4%). No special treatment was needed. The success of the examination was significantly correlated with age (OR 1.320, 95% CI 1.019-1.710, P = .035) and onset time (OR 0.959, 95% CI 0.921-0.998, P = .038).

CONCLUSION

Dexmedetomidine 3 mcg/kg combined with midazolam 0.15 mg/kg intranasally has a good sedative effect in pediatric cranial magnetic resonance examinations, little impact on breathing and circulation, and few adverse reactions. Age and onset time are related factors affecting the one-time success rate.

The Pharmacokinetics of Drugs Delivered to the Upper Nasal Space

Pharmacokinetics (PK) includes how a drug is absorbed, distributed, metabolized and eliminated. The compartment providing this information is usually the plasma. This is as close to the tissue of interest that we can get, although biopsies may be obtained to give "tissue levels" of drugs. Ultimately, the goal of PK is to understand how long the drug is actually engaged with the target in the tissue of interest after a dose has been administered. Most drugs at some point in their development will have been administered intravenously (IV), which acts as the standard for 100% bioavailability. By comparing various routes of administration to IV, the percentage of drug delivered to the plasma, on a dose-normalized basis, can be calculated and is referred to as the "absolute bioavailability". As pharmacology has advanced and more drugs have become available, many older products have been reformulated to be given by routes other than those originally intended (often oral). As the drawbacks of oral (or IV) administration have become better appreciated, non-oral, non-IV formulations and methods of administration have become more popular. Nasal administration is one route that has historically been overlooked as an alternative to oral administration-particularly for products needing rapid and non-invasive access to the target tissue-mostly via the blood stream. But attention is now focused on nasal administration for direct access to the brain, as that has the potential to bypass the blood-brain-barrier (BBB), which not even IV administration can always achieve. Assessing PK for these drugs targeting the brain may require serial sampling of the cerebrospinal fluid (CSF), making PK assessments of CNS drugs more invasive and complex, but still possible in future product development. However, we are now seeing more drugs reformulated for nasal delivery to gain faster systemic levels than oral administration (especially in patients with known or suspected gastrointestinal dysmotility), while avoiding the use of needles. For example, in recent years several different formulations and delivery methods for an old drug, dihydroergotamine (DHE), have been developed and these show very different characteristics, suggesting that delivery to different parts of the nose may have very different PK profiles. This review summarizes the systemic PK of different nasal DHE options that have been, or are being, developed and suggests that delivery of drugs to the upper nasal space (UNS) may represent an optimal target. Further research is required to ascertain if this route could also be utilized for direct administration to the CNS (as an attractive alternative to intrathecal delivery) via the olfactory or trigeminal nerves-but already preclinical data (and some human data) suggest this is entirely possible.

Clinical observation of dexmedetomidine nasal spray in the treatment of sleep disorders on the first night after undergoing maxillofacial surgery: a single-center double-blind randomized controlled study

Purpose: Dexmedetomidine exerts a sedative effect by promoting the sleep pathway endogenously and producing a state similar to N2 sleep. This study aimed to study the efficacy and safety of dexmedetomidine nasal spray in the treatment of postoperative sleep disturbance. Methods: This study enrolled 120 participants [men and women; age, 18-40 years; American Society of Anesthesiologists grade, I or II] who underwent maxillofacial surgery under general anesthesia through nasotracheal intubation. The participants were randomly divided into three groups: blank control group (BC group), 1.0 μg/kg dexmedetomidine group (1.0 Dex group), and 1.5 μg/kg dexmedetomidine group (1.5 Dex group), with 40 patients allocated to each group. At 21:30 on the night after the operation, the intervention groups were administered their corresponding doses of dexmedetomidine nasal spray. The Pittsburgh Sleep Quality Index (PSQI) scale was used to evaluate the baseline sleep status of participants 1 month preoperatively and on the night after the operation. Polysomnography (PSG) was used to record the sleep status on the night after the operation. We recorded the rescue times of sedative and analgesic drugs on the first night after surgery, adverse reactions, total hospital stay duration, and total costs. Results: Compared with patients in the BC group, those in 1.0 Dex and 1.5 Dex groups had longer N2 sleep duration, were awake for a shorter time after dose administration, woke up less often, and had significantly improved sleep efficiency (p < 0.05). Compared with the BC group, the PSQI scores of 1.0 Dex and 1.5 Dex groups were significantly lower on the night after operation, and the proportion of PSQI > 5 was significantly lower (p < 0.05). Compared with patients in the BC group and the 1.0 Dex group, those in the 1.5 Dex group had significantly prolonged N3 sleep, reduced frequency of requiring sufentanil rescue, lower incidence of sore throat after surgery, and shorter average length of hospital stay (all, p < 0.05). Conclusion: The sleep quality of participants on the night after having undergone maxillofacial surgery was safely and effectively improved by 1.0-1.5 μg/kg dexmedetomidine atomized nasal sprays. Notably, only the latter could prolong N3 sleep. Level of Evidence II: Evidence was obtained from at least one properly designed randomized controlled trial.