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Viagra tested on Everest
Agent may treat PHT
Sildenafil, an active agent used in the impotence drug Viagra, has been administered to seven young mountaineers on an Everest expedition, to test its effect on the lungs. Seven other men on the expedition are receiving a placebo.
Ardeschir Ghofrani & Friedrich Grimminger
In PHT patients blood vessels in the lung constrict, and they suffer breathlessness and cardiac strain during strenuous activities. If the condition is not diagnosed, heart failure (HF) can result. Current therapies are said to be risky, because they reduce general blood pressure and this can lead to circulatory collapse. Dr Ardeschir Ghofrani, another Geissen study team member, reported that the drug reduced PHT without causing a dangerous reduction in blood pressure elsewhere. Because a biochemical similarity exists between the penis and lungs - both contain large amounts of the enzyme phosphodiesterase - it limits penis erection and has been found to constrict blood vessels around lungs. Sildenafil blocks that enzyme, which then allows sustained erection. Similarly, in the lung walls, it appears to improve blood circulation.
Although the study results, published in the Annals of Internal Medicine, concluded that sildenafil reduced arterial pressure and improved oxygen transport, Professor Grimminger has stressed that the drug would not receive regulatory approval as a treatment for PHT until worldwide tests are completed.
Viagra was invented to treat a range cardiovascular problems but is only licensed to treat impotence. This possible new use is early stage research, said a spokesman for Pfizer, the manufacturer of Viagra, adding, by the by, that this year marks the 50th anniversary of the conquest of Everest, and it is five years since Viagra was launched.
This article was published on 07/01/2004