If you teach wilderness medicine you get used to questions about sildenafil (Viagra) and altitude illness. While there are many drugs considered as prevention or treatment of altitude illness, sildenafil seems to tweak more interest – imagine that. The questions do give me a sense of what people are talking about, and a recent inquiry on sildenafil and athletic performance sent me on a journey to look into that question.
The limited studies on sildenafil and altitude do not demonstrate it prevents acute mountain sickness (AMS).
It might be helpful in preventing High Altitude Pulmonary Edema (HAPE) in people who are susceptible to HAPE. The two operative words in that sentence are might and susceptible. There is no evidence sildenafil will prevent HAPE in the absence of a sound acclimatization practice. Said differently, Viagra probably won’t protect you if you go too high too fast.
Sildenafil is used by some physicians as part of their drug regimen when treating HAPE, but it’s not first line medication and certainly not a miracle cure. In our layperson world it doesn’t replace early recognition, descent and oxygen as the mainstays of HAPE treatment.
The question of sildenafil and athletic performance is intriguing. An article in the New York Times speaks to research into it’s effect on athletic performance. Sildenafil dilates arteries. This is how it works in erectile dysfunction, and how it is believed to help with HAPE (constricted and hypertensive pulmonary arteries are a trigger for HAPE). Dilated arteries may enhance delivery of oxygen to muscles and be a boon to athletes.
The ongoing research suggests this may be the case, maybe at sea level, perhaps more at altitude. However, there isn’t a lot of science yet, and the study I see most often referenced had only 10 participants. (J Applied Physiology June 2004). The study at Everest Base Camp had 14 participants (Annals of Internal Med 2004).
The athletic performance effect has prompted this medication to be considered as a performance enhancing medication with potential bans by those who ban such things.
Mountaineers, however, don’t need to give urine samples when they descend from a summit. Will this concept drive a new wave of Viagra use? Maybe; mountaineers and other outdoor athletes are not immune from using performance enhancing substances. It probably won’t make much impact on the drug company’s income. After all, the target for erectile dysfunction advertisements seems to be guys watching football, not altitude climbers. It might make for interesting conversations around the campfire on the question of climbing “by fair means.”