Go With the Flow

THE CHEMISTRY BEHIND TREATING ERECTILE DYSFUNCTION

drugs do just what they say: They enhance a natural process. An erection aided by drugs like Viagra starts the same way as an erection sans pharmaceuticals, with a man getting turned on. That state releases nitric oxide in a spongy tissue known as the corpus cavernosum, or, more plainly, erectile tissue. The infusion of this colorless gas stimulates production of a protein called c . hen levels of c escalate, the walls of the arteries relax, allowing more blood to ow into the penis.

But for some men, another protein, known as phosphodiesterase type , can intrude. - breaks down c . And when levels of c plunge, so does the hope of an erection.

Viagra, ialis and evitra prevent - from dismantling c . ith - restrained, levels of c are free to escalate. And the more c there is, the more relaxed the arteries become and the more blood can ow. That simple mechanism has transformed life between the sheets for millions of couples since 1998.

This (ahem) rise is not without its fall, though. ommercial erectile dysfunction drugs carry warnings against taking them simultaneously with nitrates for chest pain since the combination could cause blood pressure to plummet. That’s because nitrates break down into nitric oxide— the compound that stimulates production of c —and mixing these two medications churns out too much c . The protein left over after the arteries are relaxed ends up dilating blood vessels, and that widening forces blood pressure to drop. In the best-case scenario, a man may feel dizzy or lightheaded, but he could also pass out—or even go into potentially fatal shock. And that is not the sort of bedroom surprise anyone is looking for.