Montelukast sodium (Singulair - Merck), a leukotriene receptor antagonist, has been approved by the US Food and Drug Administration (FDA) for oral prophylaxis and chronic treatment of asthma in adults and children at least 6 years old. It is the third 'leukotriene modifier' to become available in the USA; zafirlukast (Accolate - Medical Letter, 38:111, 1996) and zileuton (Zyflo - Medical Letter, 39:18, 1997) were marketed previously. Neither zafirlukast nor zileuton has been approved by the FDA for use in children less than 12 years old. Leukotriene modifiers are not recommended for...

Mycophenolate mofetil (CellCept - Roche) has been approved by the US Food and Drug Administration for oral use in preventing organ rejection in patients receiving allogeneic renal transplants. It is being promoted as an improvement over azathioprine (Imuran) for concurrent use with cyclosporine (Sandimmune; Neoral) and corticosteroids.

RabAvert (Chiron), a new human rabies vaccine prepared in purified chick embryo cell culture (PCEC), has been marketed in the USA for pre- and post-exposure prophylaxis. It is available in other countries as Rabipur. Human rabies is rare in the United States, but thousands of people receive post-exposure prophylaxis every year (DL Noah et al, Ann Intern Med, 128:922, June 1, 1998).

Natalizumab, a recombinant humanized monoclonal antibody, has received accelerated approval from the FDA for intravenous treatment of relapsing forms of multiple sclerosis (MS). The beta interferons and glatiramer acetate are widely used for treatment of MS; they generally reduce the number of relapses by about 30% compared to placebo, and have been shown to be safe and effective for periods ranging from 4 to 10 years.

The FDA has approved apixaban (Eliquis – Bristol-Myers Squibb/Pfizer), an oral direct factor Xa inhibitor, for prevention of stroke and systemic embolism in patients with nonvalvular atrial fibrillation. It is the third new oral anticoagulant to be approved for this indication as an alternative to warfarin.

Microx (Pennwalt), a new low-dosage formulation of the thiazide-type diuretic metolazone (Zaroxolyn; Diulo), was recently marketed in the USA. The manufacturer claims that the low dose of controls hypertension with less potassium loss, making it safer than other diuretics and as effective as combination drugs, such as Dyazide, that include both a thiazide and a potassium-sparing diuretic. Medical Letter consultants generally do not recommend Dyazide or other fixed-dose combinations for treatment of hypertension.

Interim results of a double-blind, placebo-controlled trial suggest that off-label use of the anticholinergic drug oxybutynin may reduce the frequency and severity of hot flashes in women with breast cancer. Extended-release oral oxybutynin (Ditropan XL, and generics) has been shown to reduce the frequency and severity of hot flashes in healthy menopausal women.

Itraconazole (Sporanox - Janssen), an oral antifungal triazole that has been available in the USA since 1992 for treatment of deep fungal infections (Medical Letter, 35:7, 1993), is now being marketed for treatment of dermatophyte infections of the toenails, with or without fingernail involvement.

The FDA now requires boxed warnings in the package inserts of benzodiazepines describing the potential for these drugs to be abused and misused and to cause addiction and physical dependence. Benzodiazepine labels have contained a boxed warning about a risk of serious drug interactions with opioids since 2016.

Rabeprazole, a benzimidazole proton pump inhibitor similar to omeprazole and lansoprazole, has been approved by the FDA for treatment of duodenal ulcers, healing and maintenance treatment of erosive or ulcerative gastroesophageal reflux disease, and for long-term treatment of chronic hypersecretory conditions, including Zollinger-Ellison syndrome