Apo-Alfuzosin Drug Interactions

APO-ALFUZOSIN (alfuzosin hydrochloride) is not an inducer or an inhibitor of any of the principal hepatic enzymes involved in the metabolism of other drugs.
CYP3A4 is the principal hepatic enzyme iso-form involved in the metabolism of APO-ALFUZOSIN.
Potent CYP3A4 inhibitors, such as ketoconazole, itraconazole and ritonavir, increased alfuzosin hydrochloride blood levels and exposure (AUC).
Therefore, APO-ALFUZOSIN should not be co-administered with potent inhibitors of CYP3A4.
It is not known how combined exposure of any medications metabolized by the CYP3A4 hepatic enzyme isoform (such as modern alpha1-blockers), herbal remedies (particularly St. John's Wort, Milk thistle) and grapefruit juice may influence the overall efficacy and unwanted side effects of these medications, therefore, caution should be exercised.
Contraindicated combination: Ritonavir: Risk of increased plasma alfuzosin concentrations and increased undesirable effects.
Unadvised combination: Anti-hypertensive alpha-receptor blockers (prazosin, trimazosin, urapidil): Enhance hypotensive effect. Risk of severe postural hypotension.
Ketoconazole, itraconazole: Risk of increased plasma alfuzosin concentrations and increased undesirable effects.
Clarithromycin, erythromycin: Risk of increased plasma alfuzosin concentrations and increased undesirable effects.
Combination requiring precautions for use: Phosphodiesterase type 5 inhibitors (sildenafil, tadalafil, vardenafil): Risk of postural hypotension, particularly in elderly subjects. Treatment should be initiated at the lowest recommended dose and adjusted gradually if necessary.
Combination to be taken into consideration: Antihypertensives except alpha-receptor blockers: Enhanced hypotensive effect. Higher risk of postural hypotension.
Nitrates, nitrites and related drugs (isosorbide dinitrate, isosorbide, linsidomine, molsidomine, nicorandil, nitroglycerin): Increased risk of hypotension, particularly postural.