Novartis has received FDA approval to market aliskiren, a direct renin inhibitor, for the treatment of hypertension in adults. According to FDA, aliskiren is the first drug in its class to be approved by the agency. The labeling for aliskiren describes the drug as an orally active compound that decreases plasma renin activity and inhibits the conversion of angiotensinogen to angiotensin I. This, in turn, decreases circulating levels of the vasoconstrictor angiotensin II, resulting in lowered blood pressure. The labeling states that aliskiren’s antihypertensive effects were attained during the first two weeks of therapy in a set of eight-week placebo-controlled clinical trials that involved about 6500 participants. Aliskiren was then provided to these participants for up to a year for open-label studies of the drug, and the antihypertensive effects were maintained during that portion of the studies. Aliskiren can be used as monotherapy or as part of a combination regimen to treat hypertension. Most studies of combination therapy have involved aliskiren taken in conjunction with the diuretic hydrochlorothiazide or the angiotensin-receptor blocker valsartan. The labeling states that the effects of aliskiren in combination with “maximal doses” of angiotensin-converting-enzyme inhibitors have not been adequately studied.