The FDA has approved lofexidine (Lucemyra – US WorldMeds/Salix), a centrally acting alpha₂ receptor agonist, to manage withdrawal symptoms in adults abruptly stopping opioid use. Available in the UK since 1992, lofexidine is the first nonopioid to be approved in the US for management of opioid withdrawal symptoms. Clonidine (Catapres, and generics), another central alpha₂ receptor agonist, has been used off-label for this indication for many years.

The FDA has approved a subcutaneous (SC) extended-release formulation of the mu-opioid receptor partial agonist and kappa-opioid receptor antagonist buprenorphine (Sublocade – Indivior) for once-monthly treatment of moderate to severe opioid use disorder. Sublocade is the first injectable buprenorphine product to be approved in the US. Buprenorphine is also available in sublingual formulations with or without the opioid antagonist naloxone, in a buccal formulation with naloxone, and as a subdermal implant (Probuphine).

Fluvoxamine (Luvox - Solvay), a selective serotonin reuptake inhibitor (SSRI), has been approved for treatment of obsessive-compulsive disorder (OCD) by the US Food and Drug Administration. Fluoxetine (Prozac), another SSRI antidepressant, and clomipramine (Anafranil), a tricyclic antidepressant that also inhibits serotonin reuptake, are the only other drugs available for this indication in the USA. Antidepressants that do not inhibit serotonin reuptake have not been effective for treatment of this condition.

View the Comparison Table: Some Oral/Transdermal Opioid Analgesics

The FDA has approved the over-the-counter (OTC) sale of Narcan (Emergent), a nasal spray that delivers 4 mg of the opioid antagonist naloxone. Narcan nasal spray has been available by prescription since 2015 for emergency treatment of opioid overdose. Generic formulations of Narcan have also been approved; the manufacturers of these products will be required to switch them to OTC status and amend their labeling accordingly. Kloxxado, an 8-mg naloxone nasal spray, remains available only by prescription.

Nalmefene (Revex - Ohmeda), an i methylene analog of naltrexone (Trexan), is a long-acting opioid antagonist that has been approved by the US Food and Drug Administration for reversal of postoperative opioid drug effects, including respiratory depression, sedation and hypotension and for management of known or suspected opioid overdose in the emergency department. The only other opioid antagonists available in the USA are naloxone (Narcan), which is also injectable but has a short duration of action, and naltrexone, which has a long duration of action but is marketed only for oral...

The FDA has approved RiVive (Harm Reduction Therapeutics), a 3-mg naloxone nasal spray, as an over-the-counter (OTC) product for emergency treatment of opioid overdose. Two 4-mg naloxone nasal spray formulations, Narcan and one of its generics, were approved for OTC sale in 2023.

Butorphanol tartrate, a synthetic opioid agonist-antagonist analgesic previously available for injection, is now being marketed as a nasal spray (Stadol-NS - Mead Johnson). The spray was approved by the US Food and Drug Administration (FDA) for any type of pain for which an opioid analgesic is appropriate, but the manufacturer is emphasizing use for treatment of migraine headache and postoperative pain. Drugs for pain were reviewed in the Medical Letter, volume 35, page 1, January 8, 1993.

The recent increase in deaths due to overdose of heroin and prescription opioids in the US has renewed interest in the opioid antagonist naloxone, particularly in making it available to first responders and to relatives and close friends of persons using heroin or taking prescription opioids. IV or IM administration by healthcare professionals is preferred, but peripheral venous access may be difficult to obtain in IV drug abusers, and exposure to their blood may be hazardous.

Acute toxic reactions to drugs of abuse continue to be important problems. Some patients may have mixed intoxications with complex combinations of signs and symptoms.