[Sildenafil (Viagra). Tolerance, contraindications, drug interactions].

Placebo-controlled studies have clearly demonstrated the efficacy of sildenafil in the treatment of erectile dysfunction. It's tolerability cannot yet be judged definitively based on the available information. Some findings indicate that in addition to established contraindications (allergy against the active ingredient, concomitant nitrate and NO-donor treatment, retinitis pigmentosa) factors such as coronary heart disease, advanced age, impaired liver function and drug interactions require special attention by the prescribing physician to secure drug safety.