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).

Opioid use disorder is a chronic, relapsing disease with physical and psychiatric components. It is associated with economic hardship, social isolation, incarceration, increased rates of blood-borne infections such as HIV and viral hepatitis, adverse pregnancy outcomes, and increased mortality. According to the NIH, there were 80,411 deaths involving an opioid in the US in 2021, more than in any previous year. Several guidelines on the management of opioid use disorder are available; all recommend maintenance pharmacotherapy as the standard of care.

Overweight is generally defined as a body mass index (BMI) between 25 and 29.9 kg/m2 in adults. A BMI ≥30 is considered obese (criteria differ slightly in Asian patients). In patients with an elevated BMI, a 5-10% reduction in weight has been associated with a reduction in the risk of developing type 2 diabetes, hypertension, and dyslipidemia. Diet, exercise, and behavior modification are the traditional methods for losing weight, but they are often inadequate; the American College of Cardiology no longer recommends that all patients try lifestyle modification alone before adding...

The FDA has approved two antibiotics, gepotidacin (Blujepa — GSK) and zoliflodacin (Nuzolvence — Entasis), for oral treatment of uncomplicated urogenital gonorrhea in patients ≥12 years old. Gepotidacin is approved for use in persons weighing ≥45 kg who have limited or no alternative treatment options; it was approved in 2025 for treatment of uncomplicated urinary tract infection in females. Zoliflodacin is approved for use in persons weighing ≥35 kg. Neither drug is indicated for treatment of rectal or pharyngeal gonorrhea.

Many drugs, mostly imidazole derivatives, are marketed in the USA for topical treatment of vulvovaginal candidiasis, and a few are now available without a prescription.

The most effective drugs available for treatment of tobacco dependence are bupropion (Zyban, and others and varenicline (Chantix). The FDA recently ordered the manufacturers of both to add boxed warnings about the risk of psychiatric symptoms and suicide to their prescribing information (FDA Alert, 7/1/2009).

In a study of the interaction between alcohol and the calcium-channel blocker felodipine (Plendil), the grapefruit juice vehicle for the alcohol appeared to increase felodipine plasma concentrations. Subsequent studies have found that grapefruit juice increases plasma concentrations of several calcium-channel blockers and of some other drugs as well (DG Bailey et al, Clin Pharmacokinet, 26:91, 1994).

In 2013 the FDA approved one new drug and a new combination of 2 old drugs as adjuncts to lifestyle changes for chronic weight management. Lorcaserin (lor-ca-SER-in; Belviq – Arena/Esai) is a selective serotonin 2C receptor agonist. Qsymia (Vivus) is a fixed-dose combination of the weight-loss drug phentermine and an extended-release (ER) formulation of topiramate. The new products are approved for use in obese patients (body mass index [BMI] of ≥30 kg/m2) and for patients who are overweight (BMI ≥27 kg/m2) and have one weight-related risk factor such as hypertension, dyslipidemia or...

In recent years, several new drugs have been approved by the FDA for use in multiple sclerosis (MS), and many others are in the pipeline. Most recently, teriflunomide (Aubagio – Genzyme) became the second oral drug to be approved by the FDA for treatment of relapsing forms of MS.