Alprazolam, a short-acting benzodiazepine, is one of the most widely prescribed drugs in the US. It is approved by the FDA for treatment of anxiety and panic disorder. An extended-release formulation, Xanax XR, which can be taken once a day, recently became available for panic disorder.

Eplerenone (e pler' en one; Inspra - Pharmacia), an aldosterone receptor antagonist similar to spironolactone (Aldactone, and others), has been approved by the FDA, but not yet marketed, for treatment of hypertension. It has also been tried for treatment of heart failure.

Methamphetamine, a highly addictive synthetic sympathomimetic, has again become important as a drug of abuse in the US. Its resurgence has been associated with unsafe sexual practices that have resulted in an increase in HIV transmission, particularly among men who have sex with men (SJ Semple et al, J Subst Abuse Treat 2002; 22:149; A Urbina and K Jones, Clin Infect Dis 2004; 38:890).

The FDA has expanded the Emergency Use Authorizations (EUAs) for the mRNA COVID-19 vaccines manufactured by Pfizer-BioNTech (Comirnaty) and Moderna (Spikevax) to allow for their use as a second booster dose ≥4 months after a first booster dose in adults ≥50 years old and in persons aged ≥12 years (Pfizer) or ≥18 years (Moderna) who have undergone solid organ transplantation or have a condition that compromises the immune system to a similar extent.

Vardenafil (Levitra -Bayer) is the second oral drug approved by the FDA for treatment of erectile dysfunction. Sildenafil (Viagra - Medical Letter 1998; 40:51), the first oral drug, has been available for 5 years. Pharmacokinetics, effectiveness, adverse effects, dosage and cost of the new drug are reviewed. Whether it offers any benefits over sildenafil is discussed.

Alfuzosin hydrochloride (Uroxatral - Sanofi-Synthelabo) is now available in the US in a new formulation for once-daily treatment of benign prostatic hyperplasia (BPH). The drug has been used in Europe since 1987. Alpha₁-blockers cause relaxation of smooth muscle tone in the bladder neck, prostatic capsule and prostatic urethra, relieving symptoms of urinary obstruction.

The FDA has approved Biktarvy (Gilead), a once-daily, fixed-dose combination of bictegravir, a new integrase strand transfer inhibitor (INSTI), and the nucleoside reverse transcriptase inhibitors (NRTIs) emtricitabine and tenofovir alafenamide (TAF), for treatment of HIV-1 infection in adults. The new combination is indicated for use in patients who are antiretroviral-naive or who have been virologically suppressed on a stable antiretroviral regimen for ≥3 months with no history of treatment failure and no known substitutions associated with resistance to any component of the...

Tadalafil (Cialis - Lilly Icos) is the third oral drug to be approved by the FDA for treatment of erectile dysfunction. It has a longer duration of action than sildenafil (Viagra) or vardenafil (Levitra - Medical Letter 2003; 45:77).

The FDA has approved the antiviral drug remdesivir (Veklury – Gilead) for IV treatment of COVID-19 in hospitalized patients who are ≥12 years old and weigh ≥40 kg. Hospitalized children who are <12 years old or weigh <40 kg can receive remdesivir through an Emergency Use Authorization (EUA). Remdesivir is the first drug to be approved in the US for treatment of COVID-19.

View Table: Mechanisms of Drug Interactions