Objective: To assess the long-term safety and tolerability of tadalafil for patients with erectile dysfunction (ED).
Patients and methods: This was a multicentre, open-label, 24-month extension trial involving 1173 men with ED. The mean age was 57 (range 23-83) years and 74.8% of patients were taking concomitant medications for comorbid conditions, including diabetes mellitus in 30.5% of men and hypertension in 29.5%. These patients had participated in 1 of 5 previous 8-week or 12-week randomised, double-blind, placebo-controlled tadalafil studies. In the present trial, the starting 10mg dose of tadalafil could be increased to 20mg if the patient could not achieve satisfactory intercourse or reduced to 5mg for an adverse event that was persistent, intolerable and judged by the investigator to be related to tadalafil.
Results: Four hundred ninety-three (42.0%) men completed 24 months of treatment. In addition, a further 234 (19.9%) completed 18 months of treatment due to a sponsor decision to reduce the study duration. The total tadalafil exposure was 1676.0 patient-years. Tadalafil was safe and well tolerated. Headache (15.8%), dyspepsia (11.8%), nasopharyngitis (11.4%), and back pain (8.2%) were the most common treatment-emergent adverse events. The rate of discontinuations due to adverse events for this 18-24-month study was 6.3% and the rate for any individual event was <1%. Serious adverse events occurred in 8.6% of patients. No consistent pattern of serious adverse events assessed as causally associated with tadalafil administration was observed. None of the four deaths that occurred during the study was assessed as tadalafil related. There were no clinically significant laboratory or electrocardiographic findings or changes in vital signs in mean baseline-to-endpoint analysis attributable to tadalafil. Tadalafil administration was not causally associated with drug-induced hepatotoxicity, neutropenia, thrombocytopenia, or renal dysfunction.
Conclusion: Tadalafil at doses of 5, 10, or 20mg taken as needed up to once daily for 18 to 24 months was safe and well tolerated. These findings support the long-term use of tadalafil in the clinical management of erectile dysfunction.