First it was Viagra, the erectile dysfunction drug that revolutionized many lives a decade ago. Then competing drug Cialis came along, offering a longer lasting effect that was quickly nicknamed “Le Weekend” because it made you ready for action for up to 36 hours.

Now, that same drug may bring on the Endless Weekend.

Cialis, in a lower dose form, has been approved for long-term daily use for erectile dysfunction (ED).

According to an article in The Medical Letter, the traditional “on demand” dose is usually 10 or 20 mg. In Canada, the manufacturer recommends daily dosing starting at 5 mg, possibly dropping down to the 2.5 mg level if that will do the job.

The objective is to reach a steady state of the drug in the bloodstream, so that any time is the right time for love. A news release from manufacturer Eli Lilly suggests that once-daily Cialis “may be most appropriate for men with ED who anticipate more frequent sexual activity (e.g. twice weekly).”

The science behind the dose

A major study supporting this new dosing plan was led by Dr. Hartmut Porst in Hamburg, Germany. It was conducted in several countries in a double blind, randomized, placebocontrolled fashion. A total of 268 men, ranging in age from 21 to 78, were tested, all of whom who’d had erectile dysfunction symptoms for more than a year.

Almost 85 per cent of the men who took Cialis reported improved erections, while only 28 per cent of those getting a placebo said things improved in the bedroom. Even better, about half of the Cialis-taking men reported “no ED” at the end of the study.

As for side effects, the researchers write that “adverse events that occurred in at least 5 per cent of patients were dyspepsia, headache, back pain, upper abdominal pain and myalgia; nine patients (3.4 per cent) discontinued because of adverse events.”

A key finding of this work was that, if it’s taken every day, the 5 mg dose was essentially as good as 10 mg — hence the recommendation for a lower dose. Generally, doctors want to use the lowest dose possible.

There have also been suggestions that erectile dysfunction drugs may have other benefits, including effects on the circulatory system in some people. The U.S. FDA recently approved an ED drug called Revatio for a rare lung disorder called primary pulmonary hypertension. The authors of the Cialis study suggest that “daily use of PDE5 inhibitors may have further potential for non-ED and ED indications.”

Is it right for you?

It’s always worth mentioning that ED drugs like Cialis should not be used by people who take nitrates, such as nitroglycerine, because the two together can result in dangerously low blood pressure. A similar, though less severe, effect has been observed with the use of Cialis after lots of alcohol. What’s a lot of alcohol? The Eli Lilly documentation for daily dose Cialis says to be cautious if you consume five units of alcohol. It’s a little tricky to work that out, but here’s a guideline: you get about a unit of alcohol from a half pint of regular beer, a small glass of red wine or a 25 mL bar measure of hard liquor.

The marketing director for this drug at Eli Lilly & Co. was quoted as saying that the daily dose will take the pressure off men to perform within a narrow time window. It’s also likely to increase sales of the drug. At around $4 a pill, some guys will just build it into their daily budget.

But noted urologist Dr. Michael Wolff, writing on a pharmaceutical industry website, plays down the importance of the new once-a-day dosing.

He writes that it “will only appeal to a limited group of men with very active sex lives. The traditional ondemand 36-hour dosing will suffice for most men.” He suggests that this is a way for Eli Lilly to “further distinguish its product from (competing drugs) Viagra and Levitra,” which have shorter windows of opportunity.