With joint administration, the maximum dosage of Viagra mustn't exceed twenty five mg just about every forty eight hours. Inhibitors of your CYP3A4 isoenzyme (erythromycin, ketoconazole, saquinavir, itraconazole). No more than 25 mg of Sildenafil on a daily basis and strictly under the supervision of a physician. Alpha blockers. To attenuate the ch