Is there enough naloxone to deter the diversion? Effect of concurrent administration of intravenous naloxone on opioid agonist effects of intravenous buprenorphine: A randomised, double‐blind, within‐subject, crossover study among opioid‐dependent subjects

Clinical Pharmacology, Toxicity, and Abuse Potential of Opioids

Opioids were the most common drug class resulting in overdose deaths in the United States in 2019. Widespread clinical use of prescription opioids for moderate to severe pain contributed to the ongoing opioid epidemic with the subsequent emergence of fentanyl-laced heroin. More potent analogues of fentanyl and structurally diverse opioid receptor agonists such as AH-7921 and MT-45 are fueling an increasingly diverse illicit opioid supply. Overdose from synthetic opioids with high binding affinities may not respond to a typical naloxone dose, thereby rendering autoinjectors less effective, requiring higher antagonist doses or resulting in a confusing clinical picture for health care providers. Nonscheduled opioid drugs such as loperamide and dextromethorphan are associated with dependence and risk of overdose as easier access makes them attractive to opioid users. Despite a common opioid-mediated pathway, several opioids present with unique pharmacodynamic properties leading to acute toxicity and dependence development. Pharmacokinetic considerations involve half-life of the parent opioid and its metabolites as well as resulting toxicity, as is established for tramadol, codeine, and oxycodone. Pharmacokinetic considerations, toxicities, and treatment approaches for notable opioids are reviewed.

Sublingual buprenorphine-naloxone precipitated withdrawal-A case report with review of literature and clinical considerations

Buprenorphine- Naloxone Fixed Dose Combination (BNX) is widely used to manage opioid use disorders. Contrary to evidence based concepts about sublingual bio-availability of naloxone, a few small studies have reported non-negligible amounts absorbed sublingually. But the extent to which these amounts exert opioid antagonist effects is yet to be established. We hereby report the first case of opioid dependence who developed a rare phenomenon of moderate to severe opioid withdrawal symptoms on administration of sublingual BNX after several days of being stabilized on plain buprenorphine (BUP). The case demonstrates the need to consider using buprenorphine monotherapy whenever such adverse effects are encountered. We also discuss the possible pharmacological explanations behind this rare side effect.