The FDA has approved the marketing of tolvaptan (Samsca - Otsuka), an oral vasopressin receptor antagonist, for treatment of hypervolemic or euvolemic hyponatremia due to congestive heart failure (CHF), cirrhosis or the syndrome of inappropriate antidiuretic hormone secretion (SIADH). A similar drug, conivaptan (Vaprisol) is already available for intravenous (IV) treatment of euvolemic hyponatremia in hospitalized patients. Tolvaptan was approved by the FDA for both inpatient and outpatient use, but it should be started in a hospital.

The FDA has announced changes in the labeling of simvastatin to reduce the risk of myopathy. These changes include limiting the use of the 80-mg maximum dose to patients who have been taking it for 12 months or more without evidence of myopathy and new recommendations for use of simvastatin with other drugs. Simvastatin is available alone (Zocor, and others) and in combination with ezetimibe (Vytorin) and with niacin (Simcor).

Secukinumab (Cosentyx – Novartis), an injectable human interleukin (IL)-17A antagonist, has been approved by the FDA for treatment of moderate to severe plaque psoriasis in adult patients who are candidates for systemic therapy or phototherapy. It is the first IL-17 inhibitor to be approved for any indication in the US.

Voclosporin (Lupkynis – Aurinia), an oral calcineurin inhibitor, has been approved by the FDA for use in combination with the antimetabolite immunosuppressant mycophenolate mofetil (Cellcept, and generics) and a corticosteroid for treatment of adults with active lupus nephritis. It is the first calcineurin inhibitor to be approved in the US for this indication. Tacrolimus (Prograf, and others) and cyclosporine (Neoral, and others), the other available systemic calcineurin inhibitors, are approved for prophylaxis of organ rejection in transplant patients.

Silodosin (Rapaflo - Watson Pharmaceuticals), an alpha1a-adrenoreceptor selective antagonist, has been approved by the FDA for treatment of benign prostatic hyperplasia (BPH). Some medications for BPH are listed in the table on page 4. Alpha1 blockers are commonly used with 5a-reductase inhibitors such as finasteride, which can shrink the size of the prostate, but may take months to do so.

Rosuvastatin (Crestor - AstraZeneca), an HMG-CoA reductase inhibitor (or "statin"), was recently approved by the FDA for lowering serum cholesterol and triglyceride concentrations and raising HDL cholesterol levels. Rosuvastatin, like other statins, inhibits the enzyme that catalyzes the rate-limiting step in cholesterol synthesis, but it is claimed to be more potent than the others. All of these drugs must be taken indefinitely; if they are discontinued, lipid levels return to baseline.

Aliskiren (Tekturna - Novartis), the first direct renin inhibitor for treatment of hypertension, has been approved for use in a fixed-dose combination with the diuretic hydrochlorothiazide (Tekturna HCT - Novartis). Many angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) are also available in fixed-dose combinations with hydrochlorothiazide (HCTZ).

A recent letter to the editor of the Annals of Internal Medicine documented a single case of myopathy apparently due to an interaction between simvastatin (Zocor, and others) and green tea. Since it became available generically, simvastatin has surpassed atorvastatin (Lipitor) as the best selling statin. As such, it is probably the most common cause of statin-induced myopathy, which is often a result of drug interactions.

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).

The FDA has approved the marketing of fenofibric acid (Trilipix - Abbott) to reduce triglycerides and increase HDL-C in patients with mixed dyslipidemia on optimal doses of a HMG-CoA reductase inhibitor (statin) who have, or have risk factors for, coronary heart disease. It is the first fibrate approved by the FDA specifically for combined use with a statin. Trilipix is also approved as monotherapy for hypertriglyceridemia, hypercholesterolemia and low HDL-C. The patent for Tricor, Abbott's older formulation of fenofibrate, will expire in 2011.