Study suggests sildenafil may relieve severe form of edema in swimmers

Swimmers and divers who are prone to pulmonary edema in cold water (which can be deadly), could benefit from a dose of sildenafil, which is more commonly known by its brand name, Viagra®.

We all know that sildenafil can be used to treat erectile dysfunction in men, but it is also used to treat pulmonary arterial hypertension.  It works by dilating blood vessels.  In cold water swimmers and divers, their blood vessels rapidly constrict; this can lead to pooling of blood in the heart and lungs.

Athletes and swimmers with SIPE (swiming-induced pulmonary edema) cough up blood, have trouble breathing, and have low blood oxygen.  The symptoms may go away over 24 hours, but the condition can be fatal.

Researchers put 10 SIPE-susceptible athletes into a pool that mimicked the conditions that trigger SIPE.  They then compared those 10 athletes to 20 other athletes who had no history of SIPE.  The SIPE-susceptible athletes had higher pulmonary arterial pressure and pulmonary artery wedge pressure during the underwater exercise.

When the SIPE susceptible athletes were given sildenafil and performed the same exercises, their pressures were no longer as elevated.

In the words of Moon, one of the researchers, the conclusion of the study is that “It appears that the drug, which dilates the blood vessels, could be creating more capacity in the blood vessels in the arms and legs, reducing the tendency for blood to redistribute to the thorax, and therefore reducing the high pressure in the pulmonary vessels.”

This can be a promising lead on a drug that can make swimming/diving possible for people who are prone to SIPE.

The question I will pose is:  Is it better to take drugs as a preventative measure, or to take them after symptoms have developed?



Richard E. Moon, Stefanie D. Martina, Dionne F. Peacher, Jennifer F. Potter, Tracy E. Wester, Anne D. Cherry, Michael J. Natoli, Claire E. Otteni, Dawn N. Kernagis, William D. White, and John J. Freiberger. Swimming-Induced Pulmonary Edema: Pathophysiology and Risk Reduction With Sildenafil. Circulation: Journal of the American Heart Association, February 2016 DOI:10.1161/CIRCULATIONAHA.115.019464

1 thought on “Study suggests sildenafil may relieve severe form of edema in swimmers”

  1. Thank you for the post! This study definitely brings up some interesting ideas. In general I feel that prevention is considered preferable, especially when the condition can be life-threatening. In this case, how do we determine which patients should receive sildenafil prophylactically? Are there reliable risk factors (other than previous episode of SIPE) that allow us to predict who will benefit from prophylaxis? Also, the sample size for this study was quite small – perhaps larger evaluations would help answer these questions.

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