Hypertension is a major risk factor for the development of cardiovascular and 
renal disease. The incidence of hypertension is increasing globally and the rate 
of blood pressure control remains inadequate. Renin-angiotensin-aldosterone 
system (RAAS) plays a crucial role in volume regulation and maintenance of blood 
pressure. Pathological activation of RAAS results in chronic hypertension and 
consequent end organ damage. Most patients with hypertension require combination 
therapy using agents with complimentary mechanisms of action. 
Hydrochlorothiazide (HCTZ) together with an agent blocking the RAAS such as an 
angiotensin converting enzyme (ACE) inhibitor or angiotensin receptor blocker 
(ARB) are widely used effective anti-hypertensive therapy. Aliskiren is an 
orally effective direct renin inhibitor that blocks the generation of 
angiotensin I from angiotensinogen, the rate limiting step of RAAS activation. 
Studies have shown equivalent antihypertensive efficacy of aliskiren when 
compared to existing medications such as HCTZ, ACE inhibitors and ARBs. 
Aliskiren has also been tested in combination therapies. The current review aims 
to look at the efficacy of aliskiren therapy in hypertension and the evidence 
for using aliskiren in combination with HCTZ.