Angiotensin II receptor antagonist
Angiotensin II receptor antagonists, also known as
angiotensin receptor blockers (ARBs),
AT1-receptor antagonists or
sartans, are a group of pharmaceuticals which modulate the
renin-angiotensin-aldosterone system. Their main use is in
hypertension (high blood pressure),
diabetic nephropathy (kidney damage due to
diabetes) and
congestive heart failure.
These substances are AT
1-receptor antagonists â€" that is, they block the activation of
angiotensin II AT1 receptors. Blockade of AT
1 receptors directly causes
vasodilation, reduces secretion of
vasopressin, reduces production and secretion of
aldosterone, amongst other actions â€" the combined effect of which is reduction of blood pressure.
Angiotensin II receptor antagonists are primarily used for the treatment of
hypertension where the patient is intolerant of
ACE inhibitor therapy. They do not inhibit the breakdown of
bradykinin or other
kinins, and are thus only rarely associated with the persistent dry cough that commonly limits ACE inhibitor therapy. More recently, they have been used for the treatment of
heart failure in patients intolerant of ACE inhibitor therapy, particularly
candesartan. Irbesartan and losartan have trial data showing benefit in hypertensive patients with type II diabetes, and may delay the progression of
diabetic nephropathy.
This class of drugs is usually well-tolerated, with common
adverse drug reactions (ADRs) including: dizziness, headache, and/or
hyperkalaemia. Infrequent ADRs associated with therapy include: first dose
orthostatic hypotension, rash, diarrhoea,
dyspepsia, abnormal liver function, muscle cramp,
myalgia, back pain,
insomnia, decreased
haemoglobin levels,
renal impairment,
pharyngitis, and/or nasal congestion. (Rossi, 2006)
While one of the main rationales for the use of this class is the avoidance of dry cough associated with ACE inhibitor therapy, it may still rarely occur. Additionally, there is also a small risk of cross-reactivity in patients who have experienced
angioedema with ACE inhibitor therapy. (Rossi, 2006)
*
Candesartan*
Eprosartan*
Irbesartan*
Losartan*
Olmesartan*
Telmisartan*
Valsartan*Rossi S, editor.
Australian Medicines Handbook 2006. Adelaide: Australian Medicines Handbook; 2006.
