Aliskiren is the first direct renin inhibitor that was introduced for the treatment of hypertension. Aliskiren binds to the active site of renin, inhibiting the activation of the renin- angiotensin- aldosteron (RAAS) system at the rate limiting step. Aliskiren inhibits the conversion of angiotensinogen to angiotensin I (AI). This direct inhibition may be more efficient than the indirect blockade of ACE inhibitors or ARBs.