The angiotensin receptor blockers (ARBs) are a new class of agent, which are in many ways similar to the ACE inhibitors, but they do not cause cough as a side effect. Their side effects appear to be less than other classes of blood pressure lowering drugs. Angiotensin receptor blockers work in a similar way as ACE inhibitors, by blocking the effects of angiotensin, which constricts blood vessels and hence raises the pressure. But while the ACE inhibitors block the formation of angiotensin, the angiotensin antagonists block its actions, by occupying the receptors (technically called AT One receptors) which it normally activates to make the muscle cells in the blood vessels contract.