Angiotensin II receptor blockers

Angiotensin II receptor blockers

General information

Angiotensin II receptor blockers are used to treat hypertension and to reduce progression of renal disease in patients with type 2 diabetes, hypertension or microalbuminuria. Some of these agents also have an indication in heart failure and are used particularly in patients not able to tolerate an ACE inhibitor.

In contrast to the other angiotensin II receptor blockers, losartan increases uric acid excretion and effectively lowers plasma uric acid levels.

The angiotensin II receptor blockers currently available in Australia are candesartan, eprosartan, irbesartan, losartan, olmesartan and telmisartan. All except losartan are currently available on the Pharmaceutical Benefits Scheme (PBS) as single drug preparations or in combination with a low-dose thiazide.

Mechanism of action

Angiotensin II receptor blockers competitively block the binding of angiotensin to type I angiotensin II receptors and thereby reduce angiotensin-induced vasoconstriction, sodium reabsorption and aldosterone release. They have no effect on the breakdown of bradykinin.

Adverse effects

Angiotensin II receptor blockers have a similar adverse renal profile to ACE inhibitors and the same precautions apply as for ACE inhibitors 

Electrolytes and renal function should be checked before, and 1 to 2 weeks after, commencing angiotensin II blockers. They should also be reviewed after each dose increment, or if changed clinical circumstances might predispose to or indicate changes in renal function (eg dehydration, addition of a drug that can affect renal function). Angiotensin II blockers and ACE inhibitors can be used in combination provided there is close monitoring of electrolytes and renal function, as above.

Angiotensin II receptor blockers cause less cough than ACE inhibitors, and provide an alternative for people who experience this adverse effect. However, if a patient has experienced angioedema with an ACE inhibitor, angiotensin II receptor blockers are generally contraindicated, although they may be used with careful monitoring in some circumstances.