Viagra for Jet Lag?

A small dose of the impotence drug Viagra helped hamsters recover more quickly from “jet lag,” according to a study published this week in the Early Edition of PNAS.

Researcher Patricia Agostino and her colleagues injected hamsters with sildenafil, the active ingredient in Viagra, at night before turning on bright lights six hours earlier than normal – giving them a man-made dose of jet lag.

The authors then observed how the hamsters adjusted to the change by noting how soon they began running in their exercise wheels.

Sildenafil-injected hamsters recovered from the jet lag 25-50 percent more quickly than the animals that were not given the drug.

The drug, however, only worked when applied before an advance in the light/dark cycle, equivalent to an eastbound flight. It did not work in the reverse or what would be the equivalent of a westbound flight.

Based on the study's findings, scientists said frequent flyers and shift workers could benefit from moderate doses of sildenafil.

Sildenafil was originally developed for the treatment of high blood pressure and angina. It works by interfering with an enzyme that reduces levels of the naturally occurring compound, cyclic guanine monophosphate (cGMP).

In the brain, cGMP has a function in a signaling pathway that regulates the circadian cycle, also known as the body’s daily clock.