Similar to other α1-adrenergic antagonists, alfuzosin is metabolized by the hepatic microsomal enzyme system. Therefore, enzyme inhibitors and stimulators affect its metabolism. Both cimetidine and diltiazem slow hepatic metabolism of alfuzosin and increase serum levels of diltiazem. Alfuzosin has been shown to reduce the bioavailability of oral diltiazem and cause hypotension when the combination is used. The clinical importance of these interactions has not been elucidated.
Alfuzosin does not appear to interact with warfarin, digoxin, hydrochlorothiazide, or atenolol.[23,81] Caution is recommended when alfuzosin is given to patients taking other antihypertensives (e.g., angiotensinconverting-enzyme inhibitors, β-adrenergic antagonists, calcium-channel blockers) and ethanol. This is because alfuzosin shares many of the pharmacologic effects of older α1-adrenergic antagonists. Additive hypotensive effects have been previously reported with prazosin in combination with these drugs. Therefore, if using alfuzosin in patients taking antihypertensives, the lowest effective dose of alfuzosin should be used.[82,83]
Current packaging labeling for sildenafil includes a caution to avoid taking it within four hours of an α1-adrenergic antagonists to avoid a systemic hypotensive reaction as a result of the combination. Whether FDA will require such labeling for ER alfuzosin is unknown at this time.
Am J Health Syst Pharm. 2003;60(14) © 2003 American Society of Health-System Pharmacists
Cite this: Alfuzosin Hydrochloride for the Treatment of Benign Prostatic Hyperplasia - Medscape - Jul 15, 2003.