So Your Doc Gave You Viagra but You Don't Have a Penis

 So Your Doc Gave You Viagra but You Don't Have a Penis







Fig 1. Sildenafil. Source: https://compraviagraitalia.net/notizie/images/viagra.jpg 

What is Sildenafil?

Sildenafil is the active ingredient in many common vasodilators such as Viagra, Revatio, and Visarsin¹. Although most commonly noted for its ability to treat erectile dysfunction, sildenafil remains effective in treating other vascular problems such as pulmonary arterial hypertension and Raynaud’s syndrome. The IUPAC name for sildenafil is especially large which is why it is commonly referred to its brand names. Sildenafil is normally found as a crystalline, white powder² although everyone is familiar with the little blue pill commercially sold. The chemical itself is a very large molecule with a molecular formula of C₂₂H₃₀N₆O₄S showing that it is mostly comprised of carbon and hydrogen with nitrogen, oxygen, and sulphur mixed in.

How does it work?

Sildenafil shares a common shape with another organic molecule in our bodies (cGMP³) that causes smooth muscle relaxation when present in high amounts. This shape allows sildenafil to bind to the enzymes that would usually break down this molecule². Without cGMP breaking down, its level in the body rises which causes the smooth muscles in your body to relax which increases blood flow to extremities as well as the penis in males.

Should I be worried about taking it?

As with any drug you are taking you should be cautious, especially when they effect your blood pressure. Although sildenafil can be completely broken down and removed by your liver, adverse effects such as myocardial infarction, arrhythmia, cardiac arrest and hemorrhaging have be noted at dosages above 800mg⁴. There is no evidence of carcinogenicity so sildenafil is very safe to use when not used with other vasodilators.  

  ¹ Sildenafil. Drugbank. Retrieved from https://www.drugbank.ca/drugs/DB00203

  ² Sildenafil. Toxnet. Retrieved from https://toxnet.nlm.nih.gov/cgi-bin/sis/search2/f?./temp/~bRung5:1

  ³Cyclic guanosine monophosphate. Wikipedia.  Retrieved from. https://en.wikipedia.org/wiki/Cyclic_guanosine_monophosphate

   ⁴ Sildenafil. U.S National Library of Medicine. Retrieved from https://toxnet.nlm.nih.gov/cgi-bin/sis/search2/f?./temp/~DCGeIm:1