Aliskiren (Tekturna) is the first direct renin inhibitor approved for the treatment of hypertension when used alone or in combination with other antihypertensive agents. Aliskiren causes a reduction in plasma renin activity, thereby inhibiting production of angiotensin-I and -II receptor antagonists.1
|Name||Starting dosage||Dose form||Approximate monthly cost*|
|Aliskiren (Tekturna)||150 mg daily||150- or 300-mg tablets||$71|
Aliskiren has a good short-term (eight weeks) safety profile. Angioedema occurs in less than one in 1,500 patients (0.06 percent). Hyperkalemia is rare when aliskiren is used alone, but when it is combined with an angiotensin-converting enzyme (ACE) inhibitor, rates are higher by approximately 5 percent. Compared with hydrochlorothiazide (Ezide) monotherapy, a combination of aliskiren and hydrochlorothiazide will increase uric acid levels, resulting in a slight increase in the incidence of gout (0.1 versus 0.2 percent, respectively) and kidney stones (0 versus 0.2 percent, respectively). Creatine kinase will be increased in a small number of patients. Aliskiren is U.S. Food and Drug Administration pregnancy category C during the first trimester and category D during the second and third trimesters.1
Aliskiren was generally well tolerated in clinical trials. The percentage of patients taking aliskiren who dropped out because of adverse events ranged from 0.5 to 4.4 percent compared with 3.4 to 3.6 percent of patients receiving placebo.2–8 Diarrhea and cough occurred more often with aliskiren than with placebo; however, these side effects occurred in less than 3 percent of patients.1
When used alone, aliskiren in dosages of 150 to 300 mg per day will decrease systolic blood pressure by 8 to 15 mm Hg and diastolic blood pressure by 8 to 11 mm Hg. Dosages of aliskiren greater than 300 mg per day will not lower blood pressure further.2–5 When combined with hydrochlorothiazide, aliskiren will produce an additional 1 to 4 mm Hg decrease in systolic blood pressure and a 2 to 7 mm Hg decrease in diastolic blood pressure.6 Aliskiren alone produces results similar to those of the angiotensin-receptor blockers losartan (Cozaar) and irbesartan (Avapro), and it has an added effect when combined with valsartan (Diovan).2–5 Aliskiren has not been studied in combination with other antihypertensives such as calcium channel blockers, beta blockers, or alpha-adrenergic blockers. It also has not been studied in the long term, and no research has been performed to demonstrate its effect on morbidity or mortality.
Aliskiren costs approximately $71 per month. In contrast, the ACE inhibitor lisinopril (Zestril) costs about $9 to $30 for the generic version and $32 to $40 for the brand per month, and hydrochlorothiazide costs about $0.30 to $4 per month.
Aliskiren provides a new pharmacologic approach to treating hypertension; however, short-term studies have not identified a unique role. It is more expensive than commonly used first-line diuretics, and long-term safety has not been demonstrated. It is unknown if aliskiren will provide beneficial patient-orientated outcomes, such as renal protection and reduction in cardiovascular events. Aliskiren may only be valuable in patients with hypertension who are resistant to multiple-drug treatment; however, it has not yet been studied in this population.