VARDENAFIL MAY REQUIRE DOSE ADJUSTMENT IN PATIENTS RECEIVING POTENT CYP3A4 INHIBITORS SUCH AS KETOCONAZOLE, ITRACONAZOLE, RITONAVIR, INDINAVIR, SAQUINAVIR, ATAZANAVIR, AND CLARITHROMYCIN AS WELL AS IN OTHER PATIENTS RECEIVING MODERATE CYP3A4 INHIBITORS SUCH AS ERYTHROMYCIN. FOR RITONAVIR, A SINGLE DOSE OF 2.5 MG VARDENAFIL SHOULD NOT BE EXCEEDED IN A 72-HOUR PERIOD. FOR INDINAVIR, SAQUINAVIR, ATAZANAVIR, KETOCONAZOLE 400 MG DAILY, ITRACONAZOLE 400 MG DAILY, AND CLARITHROMYCIN, A SINGLE DOSE OF 2.5 MG VARDENAFIL SHOULD NOT BE EXCEEDED IN A 24-HOUR PERIOD. FOR KETOCONAZOLE 200 MG DAILY, ITRACONAZOLE 200 MG DAILY, AND ERYTHROMYCIN, A SINGLE DOSE OF 5 MG VARDENAFIL SHOULD NOT BE EXCEEDED IN A 24-HOUR PERIOD.
WHEN PDE5 INHIBITORS, LIKE VARDENAFIL, ARE USED CONCOMITANTLY WITH ALPHA-BLOCKERS BLOOD PRESSURE MAY SIGNIFICANTLY DROP DUE TO SYNERGISTIC ACTION. IN THOSE PATIENTS WHO ARE STABLE ON ALPHA-BLOCKER THERAPY, VARDENAFIL SHOULD BE INITIATED AT A DOSE OF 5 MG.