View the Expanded Table: Some Drugs for Chronic Idiopathic Constipation

The CDC has issued new guidance allowing for an interval of up to 8 weeks between the first and second primary doses of an mRNA COVID-19 vaccine in certain patients 12-64 years old.1 Product labeling currently recommends a 3-week interval between the first two doses of the Pfizer/BioNTech mRNA vaccine (Comirnaty) and a 4-week interval between the first two doses of the Moderna mRNA vaccine (Spikevax). The new guidance is based on data suggesting that a longer interval can decrease the risk of myocarditis and may improve vaccine efficacy.

The FDA has approved a generic injectable formulation of the opioid antagonist nalmefene (Purdue) for the management of known or suspected opioid overdose. Revex, the reference product, was withdrawn from the market in 2008 for commercial reasons.

The FDA has approved Cobenfy (BMS), an oral fixed-dose combination of the muscarinic agonist xanomeline and the peripheral muscarinic antagonist trospium chloride, for treatment of schizophrenia in adults. It is the first antipsychotic drug to be approved in the US for treatment of schizophrenia that does not block dopamine receptors. This is the first approval for xanomeline; trospium has been available for many years for treatment of overactive bladder.

Lecanemab-irmb (Leqembi – Eisai/Biogen), the IV amyloid-directed monoclonal antibody that received accelerated approval from the FDA in January 2023 for treatment of early Alzheimer's disease, has now received full approval from the FDA based on a trial showing that it slowed cognitive and functional decline in patients with mild cognitive impairment (MCI) or mild Alzheimer's disease dementia and confirmed presence of brain amyloid. The IV amyloid-directed monoclonal antibody aducanumab (Aduhelm) has received only an accelerated FDA-approval for the same indication.

The potassium-competitive acid blocker vonoprazan (Voquezna – Phathom), which was approved earlier for treatment of erosive esophagitis, has now been approved by the FDA for relief of heartburn associated with nonerosive gastroesophageal reflux disease (GERD) in adults. Vonoprazan is also available copackaged with amoxicillin (Voquezna Dual Pak) and with amoxicillin and clarithromycin (Voquezna Triple Pak) for treatment of Helicobacter pylori infection.

IV antiviral drug remdesivir (Veklury) has now been FDA-approved for treatment of COVID-19 in patients ≥28 days old who weigh ≥3 kg and are either hospitalized or at high risk for progression to severe disease. Remdesivir was already FDA-approved for these indications in patients ≥12 years old who weigh ≥40 kg; it was available under an Emergency Use Authorization (EUA) for younger or lighter patients. Remdesivir is the first drug to be FDA-approved for treatment of COVID-19 in children <12 years old.

View the Comparison Table: Some Drugs for Gout

View the Expanded Table: Antibiotics for Travelers' Diarrhea

A reader asked us to review use of the phosphodiesterase-5 (PDE5) inhibitor sildenafil for treatment of Alzheimer's disease (AD).