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

The FDA has approved elvitegravir (Vitekta – Gilead), an integrase strand transfer inhibitor (INSTI), for use with a protease inhibitor (PI) plus ritonavir and other antiretroviral drugs for treatment of HIV-1 infection in treatment-experienced adults. Elvitegravir is also available in a fixed-dose combination (Stribild) with the pharmacokinetic enhancer cobicistat and the nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) emtricitabine and tenofovir disoproxil fumarate (DF). A similar combination (Genvoya) that includes tenofovir alafenamide instead of tenofovir...

The FDA has approved patiromer (Veltassa – Relypsa), an oral potassium binder, for treatment of hyperkalemia. It is the first drug to be approved for this indication since the cation-exchange resin sodium polystyrene sulfonate (Kayexalate, and others) in 1958. Patiromer is not indicated for emergency correction of life-threatening hyperkalemia. Sodium zirconium cyclosilicate, another oral potassium binder, is currently being reviewed by the FDA; a decision on its approval is expected in May 2016.