Once a pharmaceutical company has a potential product, it has to go through a series of clinical trials that are designed to prove the drug does what it’s supposed to do safely. Armed with that evidence, the pharmaceutical company heads for the FDA and argues the case for approval. If the FDA agrees, the drug is licensed for the given purpose. Once released into the wild, doctors report back if there are adverse side effects and the pharmaceutical company decides whether the drug has any other possible uses. In this, the medical profession has a key role because although the FDA only gives approval for a narrow use, doctors can and do prescribe drugs "off-label", i.e. for quite different purposes, if they think the drug may have some other benefit for the patients. This leads to a grey area of medical practice where drugs are used without any government supervision or authority. But it is an important testing ground for new ideas.

In May 2009, the FDA gave its approval for a new use of tadalafil, the generic name for the 36-hour wonder drug. It always has had great potential because it achieves its effect as a treatment for erectile dysfunction by dilating the arteries leading into the penis. The system of blood vessels passes throughout the body and, if not properly dilated can cause difficulties anywhere. One such difficulty is called pulmonary arterial hypertension (PAH), a relatively uncommon condition that causes high blood pressure in the lungs. The pharmaceutical company, Eli Lilly, confirmed its effectiveness in treating PAH in a second set of clinical trials. Those participating in the randomized, double-blind trial were allocated tadalafil and a placebo. Over a period of sixteen weeks, they were encouraged to attempt exercise. At the end of the four month period, all were challenged to walk for six minutes. Those using tadalafil were able to walk an average of thirty-three meters further than those on a placebo. There was also clear evidence that the general physical condition of the participants had improved during the trial although a few suffered from the usual side effects of nasal congestion, nausea and headaches. These effects were relatively mild and passed quite quickly as participants built up tolerance.

In its form as cialis, the same side effects can affect a very small percentage of the men and those few consider the occasional headache a small price to pay for restoration of their sexual activity. Staying with the spirit of experimentation, there are also ongoing trial to determine whether the use of tadalafil gives an unfair advantage to top class athletes. There is strong evidence that the dilation of arteries not only improves the flow of blood around the body, but also increases the carriage of oxygen to the muscles. An increasing number of players who go through a drug testing regime have shown up positive for this drug. The trials are due to report later this year on whether the drug gives an unfair advantage and should be banned. Ironically, the idea that cialis turns all men in sexual athletes is great marketing copy and may, in part, be responsible for the surge in sales that has made cialis the top selling brand in many markets around the world.