Aliskiren: an oral renin inhibitor for the treatment of hypertension

Hypertension is a common chronic disease that leads to significant cardiovascular morbidity and mortality worldwide. Blood pressure control is critical in reducing the end-organ complications, such as stroke, myocardial infarction, heart failure, or kidney disease. Currently available antihypertensive agents work by different mechanisms to reduce blood pressure. Aliskiren, a novel direct renin inhibitor, lowers blood pressure by decreasing renin activity, and angiotensin I and II levels. At the approved dosage (150-300 mg once daily), it reduces systolic blood pressure by 12-16 mm Hg and diastolic blood pressure by 2-12 mm Hg. In studies its efficacy was comparable to losartan 100 mg, irbesartan 150 mg, and valsartan 80-320 mg. When used adjunctively with ramipril, an angiotensin-converting enzyme (ACE) inhibitor, valsartan, an angiotensin II receptor blocker (ARB), or hydrochlorothiazide, a diuretic, it provides additional blood pressure reduction compared with placebo or monotherapy. Aliskiren is well tolerated, with the most common side effects being gastrointestinal symptoms, fatigue, weakness, and headache. In short-term clinical trials, aliskiren caused fewer disturbances in potassium levels when compared with hydrochlorothiazide, ACE inhibitors and ARBs. Long-term data on morbidity and mortality outcomes are not currently available, thus it is unknown whether aliskiren would join ACE inhibitors and ARBs as the preferred hypertensive agents for end organ protection. At this time, aliskiren should be considered as an alternative agent for mild-to-moderate hypertension, or as an adjunctive therapy when preferred agents fail to maintain optimal blood pressure control. It is also an option for those patients who have contraindications or intolerability to other antihypertensive agents, including dry cough induced by ACE inhibitors.