Abstract: A pharmaceutical administration system for the transdermal application of at least one active agent includes vardenafil and/or a pharmaceutically acceptable salt thereof as the active agent and a pharmaceutically acceptable carrier providing a solution of the at least one active agent in the administration system. Another active agent may be testosterone. This system can be used to systemically deliver therapeutic doses of vardenafil and/or a pharmaceutically acceptable salt thereof and optionally testosterone in order to treat benign prostatic hyperplasia, erectile dysfunction, male hypogonadism, pulmonary hypertension, and/or pulmonary arterial hypertension.