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.

Pharmacologic management of opioid withdrawal symptoms can reduce the intensity of drug craving and improve treatment retention in patients with opioid use disorder who will receive maintenance treatment. Withdrawal management without subsequent maintenance treatment is associated with high rates of relapse, overdose death, and HIV and/or hepatitis C virus infection. Several guidelines on management of opioid withdrawal are available. Maintenance treatment of opioid use disorder was reviewed in a previous issue.

Tetrabenazine (Xenazine - Ovation Pharmaceuticals), an old drug first synthesized 50 years ago for treatment of schizophrenia, was recently approved by the FDA for the treatment of chorea associated with Huntington's disease. It has been available in other countries for decades.

The FDA has approved a sublingual film formulation of the alpha-2 adrenergic receptor agonist dexmedetomidine (Igalmi — BioXcel Therapeutics) for acute treatment of agitation associated with schizophrenia or bipolar I or II disorder in adults. It is the first alpha-2 agonist and the only sublingual film to be approved for this indication. Dexmedetomidine has been available for many years in an injectable formulation (Precedex) for sedation in the intensive care unit and to facilitate procedures such as mechanical ventilation.

The FDA has approved the opioid agonist hydromorphone in a once-daily extended-release (ER) oral tablet formulation (Exalgo – Covidien) for the management of moderate to severe pain in opioid-tolerant patients requiring continuous, long-term therapy. Another hydromorphone ER formulation (Palladone – Purdue) was available previously, but was withdrawn from the market because taking it with alcohol could interfere with the extended-release mechanism and lead to rapid release of potentially lethal amounts of the drug ("dose-dumping").

Anascorp (Rare Disease Therapeutics), an intravenously administered antivenom derived from horse serum, has been approved by the FDA for treatment of clinical signs of scorpion envenomation.

Ashwagandha is an herb extracted from the roots of an evergreen shrub (Withania somnifera) found in India that has been used as a "tonic" for centuries. No specific constituent has been identified as an active ingredient. Herbal supplements containing ashwagandha, which is also known as winter cherry and Indian ginseng, are widely promoted now in the US for treatment of pain, anxiety, stress, fatigue, sleep disturbances, cognitive decline, diabetes, arthritis, male infertility, and various cancers.

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.

Changes caused by one drug in the absorption, distribution, metabolism or excretion of another may lead to a pharmacokinetic adverse drug interaction (DN Juurlink et al, JAMA 2003; 289:1652). Additive drug interactions, such as vasodilation caused by both sildenafil (Viagra) and nitrates, can also have adverse effects.

The ability of grapefruit juice to increase serum concentrations of drugs was first discovered during a study of the effect of ethanol on felodipine (Plendil) pharmacokinetics. Double-strength grapefruit juice used to disguise the taste of ethanol resulted in higher than expected serum concentrations of felodipine (DG Bailey et al, Clin Invest Med 1989; 12:357).