Tadalafil, a further innovation in the treatment of sexual dysfunction

In recognition of the large number of sufferers of sexual dysfunction worldwide, and the variety of etiologies of the condition, investigation into effective pharmacological agents has been expanded. One method of intervention is inhibition of the phosphodiesterase type 5 (PDE5) enzyme, which has already been exploited with a considerable degree--though not complete--success. A number of new agents that inhibit PDE5 are under development. Notable among these is tadalafil, which has demonstrated a high level of selectivity for PDE5 over the other phosphodiesterases and has shown efficacy in improving erectile function and sexual satisfaction in phase III trials. Throughout the clinical development program for tadalafil, the drug has been well tolerated and without serious side effects. The manufacturer, Lilly ICOS, received an approvable letter from the US Food and Drug Administration for use of the drug as a treatment for erectile dysfunction on April 30, 2002. Lilly ICOS hopes to market tadalafil, with the trade name Cialis, in the USA in 2003.