For men with erectile dysfunction, but who want to be ready whenever opportunity presents itself, the U.S. Food and Drug Administration has approved a once-a-day dose of Cialis, the ED drug made by Eli Lilly and Company.

The Indianapolis-based pharmaceutical firm says when Cialis for once daily use is taken daily, men can attempt sexual activity at anytime between doses.

Currently available in parts of Europe, this low-dose daily treatment option of Cialis may be most appropriate for men with ED who anticipate sexual activity of twice a week or more, the company said. For other men, Cialis taken as needed - the previously approved dosing regimen - may be most appropriate.

In clinical trials, when taken without restrictions on the timing of sexual activity, Cialis for once daily use improved erectile function over the course of therapy, according to Lilly.

"ED can be a chronic condition like diabetes or high blood pressure," said Ridwan Shabsigh, M.D., Director of the Division of Urology at Maimonides Medical Center in New York. "As a urologist, I know couples like to have choices and will appreciate the availability of Cialis for once daily use."

Cialis for use as needed came on the market in 2003 and, the company says, has proven to provide sustained efficacy for up to 36 hours. Cialis for once daily use provides a new option for men who may be looking for a dosing option that can be taken without regard to timing of sexual activity.

Lilly's wholesale pricing for Cialis for once daily use will be comparable to Cialis for use as needed, so that patients who currently use two or more pills per week of Cialis for use as needed should not experience higher treatment costs with Cialis for once daily use.

Lilly said the FDA's approval of Cialis for once daily use was based upon the evaluation of the comprehensive data package for the daily dosing option.

The data include results from three phase III randomized, double-blind, placebo- controlled studies. Men with ED who participated in these clinical studies and who took tadalafil 2.5 mg and 5 mg once daily without regard to their timing of sexual activity experienced improved erectile function compared with those taking placebo.

Cialis 5 mg, 10 mg and 20 mg have been approved in the United States for as-needed treatment of ED since November 2003.