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.

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 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.

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.

The FDA has approved the use of the 5α-reductase inhibitor dutasteride (Avodart - GlaxoSmithKline) together with the alpha₁-blocker tamsulosin (Flomax - Boehringer Ingelheim) for treatment of benign prostatic hyperplasia (BPH). Use of an alpha1-blocker with a 5α-reductase inhibitor has been a common practice for years, but FDA approval of a particular combination permits the manufacturers to add an indication for it in both package inserts, recommend dosage for combination use, and advertise the benefits of using the 2 drugs together.

Treprostinil sodium (tre prost' in il; Remodulin - United Therapeutics), a prostacyclin analogue, has been approved by the FDA for continuous subcutaneous (SC) treatment of patients with pulmonary arterial hypertension who have dyspnea on more than minimal exertion (NYHA Class II-IV).

Since publication of our recent article on antiviral drugs for influenza, increased levels of resistance to oseltamivir (Tamiflu) have been detected in influenza A H1N1 strains.