nitroglycerin causes vasodilation--why doesn't it cause erection?
October 4, 2013 6:35 PM   Subscribe

Nitroglycerin is used to treat angina by causing vasodilation of the blood vessels around the heart. Flushing is one of the side effects, indicating that vasodilation is not specific to only the heart. Do people use nitro to treat erectile dysfunction? Can erection be a side effect of nitro? Phosphodiesterase type 5 (PDE-5) inhibitors (viagra) cause vasodilation and are not supposed to be used in combination with nitroglycerin for risk of severe drops in blood pressure. This made me wonder how these drugs are specific. Why couldn't nitro be used for the penis in addition to the heart?
posted by chrysanthemum to Science & Nature (10 answers total) 6 users marked this as a favorite

There is indeed a nitro ointment available for that very purpose.
posted by mittens at 6:44 PM on October 4, 2013

Zanifil gel, marketed by Durex inside a condom.
posted by quercus23 at 6:46 PM on October 4, 2013

Response by poster: Ok. So it has to just be applied directly? Why doesn't nitro when taken for angina cause erection? Or why couldn't people with angina and erectile dysfunction just pop more nitro? Or do they?
posted by chrysanthemum at 6:47 PM on October 4, 2013

I can't say specifically the nitro is/was ever used for ED. But I do know that Viagra was originally intended as a blood pressure/angina treatment but in practice, it had a more lucrative 'side effect' that has been marketed instead.
posted by Tandem Affinity at 7:04 PM on October 4, 2013

The boner pills aren't simply general vasodilators, they are specific inhibitors of the degredation of the stuff which leads to vasoconstriction right in the weiner area. So Viagra works strongly and specifically on your penis. Yes, it has some effect on other areas but it is most strongly felt in that region.

The molecule in question which Viagra blocks is PDE5. cGMP-specific phosphodiesterase type 5, which is in the corpus cavernosum. IE, the weiner.
posted by Justinian at 7:14 PM on October 4, 2013 [15 favorites]

Viagra inhibits on PDE-5, which is found most prominently in the corpus cavernosum of the penis. Since PDE-5 destroys the vasodilatator cGMP, inhibiting it makes for more cGMP, hence erection.

Nitroglycerin in transformed into NO, which is a vasodilatator. It doesn't have a location-specific mechanism like Viagra.
posted by Monday, stony Monday at 7:15 PM on October 4, 2013

Oh, fwiw the other area PDE5 is found the most in is your retina. That's why boner pills come with warnings about loss of vision or your vision turning blue or whatever.
posted by Justinian at 7:15 PM on October 4, 2013

A nitroglycerin cream applied to a man's penis would be dangerous to his woman partner; it could cause her blood pressure to crash.
posted by Chocolate Pickle at 7:23 PM on October 4, 2013

Best answer: It does cause an erection, and it was a big party drug at one time: poppers.
posted by jamjam at 9:07 AM on October 5, 2013 [2 favorites]

Chocolate Pickle: A nitroglycerin cream applied to a man's penis would be dangerous to his woman partner; it could cause her blood pressure to crash.

That explains why it's sold as a gel inside a condom, but not generally as an ointment.
posted by IAmBroom at 11:17 AM on October 6, 2013

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