Investigators evaluated the ability of Levitra to provide reliable efficacy over time in a broad population of men with ED. They analyzed data from a phase III, randomized, double-blind study in which 805 men, including 100 Canadian men with ED and 11 Canadian trial sites, received Levitra 5, 10 or 20 mg or placebo for up to 26 weeks. The analysis showed that at a 20 mg dose: On average men were successful in 74 per cent of their first attempts in penetrating their partner compared with 46 per cent of men taking placebo. Of those men taking Levitra who were successful the first time, they continued to achieve successful penetration in 91 per cent of subsequent attempts.

Study shows improvement in erection quality following prostate cancer surgery in patients taking Levitra. In another study – the first of its kind to assess the effect of a phosphodiesterase (PDE-5) inhibitor on erectile function and depressive symptoms among men with ED resulting from prostate cancer surgery – men taking Levitra were more likely to report improved erections and fewer depressive symptoms than men taking placebo.

In another phase III clinical trial, 440 men aged 44 to 77 years with ED following prostatectomy and who experienced ED for six months before entering the study, were randomly assigned to placebo or Levitra (at a dose of 10 or 20 mg) for 12 weeks. This study included 24 Canadian trial sites with 176 patients. After 12 weeks: up to 71 per cent of patients who had undergone a specific type of prostatectomy, known as bilateral nerve-sparing prostatectomy, reported statistically significant improvement in erections with Levitra 20 mg versus 12 per cent of men taking placebo. A significant decrease in depressive symptoms was observed among a small subset of depressive prostatectomy patients taking Levitra 20 mg. Men who suffer from ED following prostatectomy are among the most difficult to treat because their ED is typically severe. In these studies, Levitra related adverse events were reported as generally mild to moderate in intensity with the most frequent Levitra adverse events being headache, flushing and rhinitis.

Side Effects
Those involved in the clinical trials reported mild / moderate side effects with Levitra, these mostly included headaches, flushing and rhinitis (nasal congestion).

Precautions
Levitra should not be taken if you are taking nitrates or nitric oxide donors (these medications are used to treat angina or chest pain). Levitra is also contraindicated in men whom sex is inadvisable and men older than 75 years old who concomitantly use potent CYP 3A4 inhibitors (such as ritonavir, indinavir, ketoconazole and itraconazole). The safety of Levitra has not been studied in these subgroups and should not take Levitra until further studies are available: severe hepatic (liver system) impairment, end stage renal disease requiring dialysis, hypotension, recent history of stroke or heart attack, unstable angina, and known hereditary retinal degenerative disorders.

Drug interactions:
Tell your online doctor of all nonprescription and prescription medication you may use, especially any nitrate medications (e.g., nitroglycerin, isosorbide dinitrate), nitroprusside (any "nitric oxide donor" medicines), cimetidine, erythromycin, azole antifungals (e.g., itraconazole, ketoconazole), mibefradil, rifamycins (e.g., rifampin) or high blood pressure medicines.