Buprenorphine: An anesthesia-centric review

Buprenorphine was synthesized in the 1960s as a result of a search for a safe and effective opioid analgesic. Present formulations of buprenorphine are approved for the treatment of both acute and chronic pain. Its long duration of action, high affinity, and partial agonism at the µ-opioid receptor have established it as a mainstay treatment for opioid use disorder (OUD). Full agonist opioids (FAOs) remain a primary choice for perioperative pain in both opioid-naïve and opioid-tolerant patients despite well-known harms and new emphasis on multimodal analgesia strategies prioritizing nonopioid analgesics. We review the evidence supporting the use of buprenorphine as an effective analgesic alternative to more commonly prescribed FAOs in acute and chronic pain management. For the patient prescribed buprenorphine for OUD, prior conventionalism advised temporary discontinuation of buprenorphine preoperatively; this paradigm has shifted toward continuing buprenorphine throughout the perioperative period. Questions remain whether dose adjustments may improve patient outcomes.

The efficacy of buprenorphine compared with dexmedetomidine in spinal anesthesia: a systematic review and meta-analysis

BACKGROUND

This study compares dexmedetomidine and buprenorphine as potential adjuvants for spinal anesthesia. Dexmedetomidine enhances sensory block and minimizes the need for pain medication, while buprenorphine, a long-acting opioid, exhibits a favorable safety profile compared to traditional opioids.

METHODS

PubMed, Cochrane and EMBASE were systematically searched in December 2023.

ELIGIBILITY CRITERIA

RCTs with patients scheduled for lower abdominal, pelvic, or lower limb surgeries; undergoing spinal anesthesia with a local anesthetic and buprenorphine or dexmedetomidine.

RESULTS

Eight RCTs involving 604 patients were included. Compared with dexmedetomidine, buprenorphine significantly reduced time for sensory regression to S1 (Risk Ratio [RR = -131.28]; 95% CI -187.47 to -75.08; I2 = 99%) and motor block duration (RR = -118.58; 95% CI -170.08 to -67.09; I2 = 99%). Moreover, buprenorphine increased the onset time of sensory block (RR = 0.42; 95% CI 0.03 to 0.81; I2 = 93%) and increased the incidence of postoperative nausea and vomiting (RR = 4.06; 95% CI 1.80 to 9.18; I² = 0%). No significant differences were observed in the duration of analgesia, onset time of motor block, time to achieve the highest sensory level, shivering, hypotension, or bradycardia.

CONCLUSIONS

The intrathecal administration of buprenorphine, when compared to dexmedetomidine, is linked to reduction in the duration of both sensory and motor blocks following spinal anesthesia. Conversely, buprenorphine was associated with an increased risk of postoperative nausea and vomiting and a longer onset time of sensory block. Further high-quality RCTs are essential for a comprehensive understanding of buprenorphine's effects compared with dexmedetomidine in spinal anesthesia.

Local Anesthetics, Local Anesthetic Systemic Toxicity (LAST), and Liposomal Bupivacaine

Local anesthetics have played a vital role in the multimodal analgesia approach to patient care by decreasing the use of perioperative opioids, enhancing patient satisfaction, decreasing the incidence of postoperative nausea and vomiting, decreasing the length of hospital stay, and reducing the risk of chronic postsurgical pain. The opioid-reduced anesthetic management for perioperative analgesia has been largely successful with the use of local anesthetics during procedures such as peripheral nerve blocks and neuraxial analgesia. It is important that practitioners who use local anesthetics are aware of the risk factors, presentation, and management of local anesthetic systemic toxicity (LAST).

A synopsis of multitarget therapeutic effects of anesthetics on depression

Depression is a profound mental disorder that dampens the mood and undermines volition, which exhibited an increased incidence over the years. Although drug-based interventions remain the primary approach for depression treatment, the available medications still can't satisfy the patients. In recent years, the newly discovered therapeutic targets such as N-methyl-D-aspartate (NMDA) receptor, α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptor, and tyrosine kinase B (TrkB) have brought new breakthroughs in the development of antidepressant drugs. Moreover, it has come to light that certain anesthetics possess pharmacological mechanisms intricately linked to the aforementioned therapeutic targets for depression. At present, numerous preclinical and clinical studies have explored the therapeutic effects of anesthetic drugs such as ketamine, isoflurane, N2O, and propofol, on depression. These investigations suggested that these drugs can swiftly ameliorate patients' depression symptoms and engender long-term effects. In this paper, we provide a comprehensive review of the research progress and potential molecular mechanisms of various anesthetic drugs for depression treatment. By shedding light on this subject, we aim to facilitate the development and clinical implementation of new antidepressant drugs based on anesthetic medications.

Local Anesthetics, Local Anesthetic Systemic Toxicity (LAST), and Liposomal Bupivacaine

Local anesthetics have played a vital role in the multimodal analgesia approach to patient care by decreasing the use of perioperative opioids, enhancing patient satisfaction, decreasing the incidence of postoperative nausea and vomiting, decreasing the length of hospital stay, and reducing the risk of chronic postsurgical pain. The opioid-reduced anesthetic management for perioperative analgesia has been largely successful with the use of local anesthetics during procedures such as peripheral nerve blocks and neuraxial analgesia. It is important that practitioners who use local anesthetics are aware of the risk factors, presentation, and management of local anesthetic systemic toxicity (LAST).

To evaluate the efficacy of buprenorphine and 2% lignocaine with adrenaline as postoperative analgesia following mandibular third molar surgery: A comparative study

Introduction:

Opioid analgesics have an advantage over nonsteroidal anti-inflammatory drugs in that they do not cause direct organ damage. Buprenorphine has an antinociceptive potency approximately 25–50 times greater than that of morphine. Hence, in this study, buprenorphine was added to local anaesthesia in relieving postoperative pain after lower third molar surgery when given as inferior alveolar nerve block. The aim of this study was to evaluate the efficacy of buprenorphine in managing postoperative pain after lower third molar surgery.

Materials and Methods:

Fifty patients requiring lower third molar surgery were randomly divided into two groups. Group A received buprenorphine added to 2% lignocaine with 1:80,000 adrenaline and Group B received 2% lignocaine with 1:80,000 adrenaline. Parameters assessed were onset of anaesthesia, depth of anaesthesia, intraoperative monitoring of adverse effects, duration of analgesia, and number of analgesics consumed. Statistical analysis was carried out using SPSS software version 21. The data were compared using Student's t-test. The level of significance was set at 0.05.

Results:

There was a significant difference in onset of anaesthesia between Group A and Group B (P < 0.05). Depth of anaesthesia and duration of analgesia were greater in Group A (56 h 36 min) than Group B (3 h 24 min). Analgesics consumed by Group A (0.9) were significantly less compared to Group B (9.2) and it was highly significant (P = 0.000).

Discussion:

Buprenorphine when added to local anaesthesia can prolong postoperative analgesia with minimum or no side effects. Hence, buprenorphine can be safely used for lower third molar surgery.

Participation of the opioid receptor - nitric oxide - cGMP - K+ channel pathway in the peripheral antinociceptive effect of nalbuphine and buprenorphine in rats

The aim of this study was to examine if the peripheral antinociceptive effects of the opioid agonist/antagonist nalbuphine and buprenorphine involve the sequential participation of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) synthesis followed by K⁺ channel opening in the formalin test. Wistar rats (180-220 g) were injected in the dorsal surface of the right hind paw with formalin (1%). Rats received a subcutaneous (s.c.) injection into the dorsal surface of the paw of vehicles or increasing doses of nalbuphine (50-200 μg/paw) or buprenorphine (1-5 μg/paw) 20 min before formalin injection into the paw. Nalbuphine antinociception was reversed by the s.c. injection into the paw of the inhibitor of NO synthesis (N^G-nitro-l-arginine methyl ester (L-NAME)), by the inhibitor of guanylyl cyclase (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ)), by the K_ir6.1-2, ATP-sensitive K⁺ channel inhibitors (glibenclamide and glipizide), by the K_Ca2.1-3, small conductance Ca²⁺-activated K⁺ channel blocker (apamin), by the K_Ca1.1, large conductance Ca²⁺-activated K⁺ channel blocker (charybdotoxin), and by the K_V, voltage-dependent K⁺ channel inhibitors (4-aminopyridine (4-AP) and tetraethylammonium chloride (TEA)). The antinociceptive effect produced by buprenorphine was blocked by the s.c. injection of 4-AP and TEA but not by L-NAME, ODQ, glibenclamide, glipizide, apamin, or charybdotoxin. The present results provide evidence for differences in peripheral mechanisms of action between these opioid drugs.

Review of adjuvants to local anesthetics in peripheral nerve blocks: Current and future trends

In recent anesthetic practice, peripheral nerve blocks (PNBs) are used extensively for surgical anesthesia and nonsurgical analgesia. PNBs offer many benefits over other anesthetic techniques in a certain population of patients, and in some specific clinical setting, that may contribute to faster and safer pain relief, increased patient satisfaction, reduced hospital stay, and decreased overall healthcare cost. The technique involves the injection of the anesthetic in the vicinity of a specific nerve or bundle of nerves to block the sensation of pain transmitting to a specific portion of the body. However, the length of analgesia when a single anesthetic is used for PNB may not last long. Therefore, the practice of adding an additional agent called adjuvant has been evolved to prolong the analgesic effect. There are many such adjuvants available that are clinically being used for this purpose imparting great efficacy and safety to the anesthetic process. The adjuvants molecules are generally classified as opioids, alpha-2 agonist, steroids, etc. Most of them are safe to use and show little or no adverse event related to neurotoxicity and tissue damage. Although there is extensive use of such adjuvants in the clinical field, none of the molecules is approved by the FDA and is used as an off-label drug. The risk to benefit ratio must be assessed while using such an agent. This review will try to delineate the basic need of adjuvant in peripheral nerve block and will discuss the advantages and limitations of using different adjuvants and will discuss the future prospect of such application.

Adjuvants in clinical regional anesthesia practice: A comprehensive review

Adjuvants are medications that work synergistically with local anesthetics to help enhance the duration and quality of analgesia in regional techniques. Regional anesthesia has become more prevalent as evidence continues to show efficacy, enhancement of patient care, increased patient satisfaction, and improved patient safety. Practitioners in the perioperative setting need to not only be familiar with regional techniques but also the medications used for them. Some examples of adjuvant medications for regional techniques include dexamethasone, alpha 2 agonists such as clonidine and dexmedetomidine, midazolam, buprenorphine, NMDA antagonists, including ketamine and magnesium, neostigmine, sodium bicarbonate, epinephrine, and non-steroidal anti-inflammatory drugs. The aim of the present investigation, therefore, is to provide a comprehensive review of the most commonly used non-opioid adjuvants in clinical practice today. Regional adjuvants can improve patient safety, increase patient satisfaction, and enhance clinical efficacy. Future studies and best practice techniques can facilitate standardization of regional anesthesia adjuvant dosing when providing nerve blocks in clinical practice.

Treating Chronic Pain: An Overview of Clinical Studies Centered on the Buprenorphine Option

The buprenorphine receptor binding profile is unique in that it binds to all three major opioid receptors (mu, kappa, delta), and also binds to the orphan-like receptor, the receptor for orphanin FQ/nociceptin, with lower affinity. Within the mu receptor group, buprenorphine analgesia in rodents is dependent on the recently discovered arylepoxamide receptor target in brain, which involves a truncated 6-transmembrane mu receptor gene protein, distinguishing itself from morphine and most other mu opioids. Although originally designed as an analgesic, buprenorphine has mainly been used for opioid maintenance therapy and only now is increasingly recognized as an effective analgesic with an improved therapeutic index relative to certain potent opioids. Albeit a second-, third-, or fourth-line analgesic, buprenorphine is a reasonable choice in certain clinical situations. Transdermal patches and buccal film formulations are now commercially available as analgesics. This review discusses buprenorphine pharmacodynamics and pharmacokinetics, use in certain populations, and provides a synopsis of systematic reviews and randomized analgesic trials. We briefly discuss postoperative management in patients receiving buprenorphine maintenance therapy, opioid equivalence to buprenorphine, rotations to buprenorphine from other opioids, and clinical relevance of buprenorphine-related QTc interval changes.

A study on the safety evaluation of buphrenorphine administered through an autoinjector compared with manual injection using haematological and biochemical variables in rats

Buprenorphine drug cartridge was made for autoinjector device for use in emergency and critical situations to reduce the morbidity and mortality. Water-filled cartridges were prepared and buprenorphine was injected aseptically in the cartridge, to make 0.05 and 0.10 mg/mL. Rats were injected intraperitoneally, buprenorphine (0.3 and 0.6 mg/kg), repeatedly with the autoinjector and compared with manual injection (7 days and 14 days) using various haematological and biochemical parameters. No significant change was observed in the body weight, organ to body weight ratio and haematological variables in any of the experimental groups compared with the control group. Except serum urea and aspartate aminotransferase, no significant change was observed in glucose, cholesterol, triglycerides, bilirubin, protein, albumin, creatinine, uric acid, alanine aminotransferase, gamma glutamyltransferase and alkaline phosphatase. The autoinjectors deliver the drugs with spray effect and force for faster absorption. In the present study, the autoinjector meant for intramuscular injection was injected intraperitoneally in rats, and the drug was delivered with force on the vital organs. No significant difference was observed in the autoinjector group compared to the manual group showing tolerability and safety of the buphrenorphine autoinjector. This study shows that buprenorphine autoinjector can be considered for further research work.

Upper extremity nerve block: how can benefit, duration, and safety be improved? An update

Upper extremity blocks are useful as both sole anaesthesia and/or a supplement to general anaesthesia and they further provide effective postoperative analgesia, reducing the need for opioid analgesics. There is without doubt a renewed interest among anaesthesiologists in the interscalene, supraclavicular, infraclavicular, and axillary plexus blocks with the increasing use of ultrasound guidance. The ultrasound-guided technique visualising the needle tip and solution injected reduces the risk of side effects, accidental intravascular injection, and possibly also trauma to surrounding tissues. The ultrasound technique has also reduced the volume needed in order to gain effective block. Still, single-shot plexus block, although it produces effective anaesthesia, has a limited duration of postoperative analgesia and a number of adjuncts have been tested in order to prolong analgesia duration. The addition of steroids, midazolam, clonidine, dexmedetomidine, and buprenorphine has been studied, all being off-label when administered by perineural injection, and the potential neurotoxicity needs further study. The use of perineural catheters is an effective option to improve and prolong the postoperative analgesic effect.

Upper extremity plexus blocks have an obvious place as a sole anaesthetic technique or as a powerful complement to general anaesthesia, reducing the need for analgesics and hypnotics intraoperatively, and provide effective early postoperative pain relief. Continuous perineural infusion is an effective option to prolong the effects and improve postoperative quality.