Irbesartan inhibits the activity of
angiotensin II (AII) via specific, selective noncompetitive antagonism of the AII receptor subtype 1 (AT1) which mediates most of the known physiological activities of AII. In patients with mild to moderate
hypertension, once daily administration of
irbesartan 150 or 300 mg, with or without adjunctive
antihypertensive agents, provides effective 24-hour BP control.
Irbesartan reduced BP to a similar extent to
enalapril and
atenolol and to a significantly greater extent than
losartan. The combination of
irbesartan and
hydrochlorothiazide resulted in additive
antihypertensive effects. The
drug is effective in the elderly and dosage adjustment is not required in these patients or in those with renal or
hepatic failure. Preliminary studies evaluating the efficacy of
irbesartan in patients with
heart failure have produced encouraging results.
Irbesartan is very well tolerated and neither the frequency nor the pattern of adverse events differed from those seen in placebo recipients, although
headache was significantly more frequent with the latter. Similarly, the incidence of adverse events did not differ significantly between
irbesartan and
enalapril in patients who received either
drug as monotherapy.
Headache,
upper-respiratory tract infection and
musculoskeletal pain were the most common complaints. Thus,
irbesartan is an effective
therapy for patients with mild to moderate
hypertension and had an adverse event profile similar to that of placebo in clinical trials. On this basis it would appear to be an effective therapeutic option in this indication.