The antihypertensive effects of irbesartan may be potentiated by drugs or other agents that lower blood pressure. NSAIDS should be used with caution in patients taking irbesartan as the risk of renal impairment may be increased, particularly in those who are inadequately hydrated; use of NSAIDs may also attenuate the hypotensive effect of irbesartan. Irbesartan and some other angiotensin II receptor antagonists are metabolized by cytochrome P450 isoenzymes and interactions may occur with drugs that effect these enzymes.