Benzamidenafil (Xanthoanthrafil) is a synthetic drug that acts as a PDE5 inhibitor. It has the same mechanism of action as pharmaceutical drugs used to treat erectile dysfunction, but it is not approved by any regulatory agency for such use. The (R) enantiomer is the active form, and was previously patented under the code FR226807.Hosogai N, Hamada K, Tomita M, Nagashima A, Takahashi T, Sekizawa T, Mizutani T, Urano Y, Kuroda A, Sawada K, Ozaki T, Seki J, Goto T. FR226807: a potent and selective phosphodiesterase type 5 inhibitor. Eur J Pharmacol. 2001 Oct 5;428(2):295-302. Kumasaka K, Kawahara N, Doi K, Kojima T, Goda Y. Determination of (R)-xanthoanthrafil, a phosphodiesterase-5 inhibitor, in a dietary supplement promoted for sexual enhancement. Chem Pharm Bull (Tokyo). 2008 Feb;56(2):227-30. It has also been used for research into other potential therapeutic applications of PDE5 inhibitors such as in the treatment of nephrotoxicity.Hosogai N, Tomita M, Hamada K, Ogawa T, Hirosumi J, Manda T, Mutoh S. Phosphodiesterase type 5 inhibition ameliorates nephrotoxicity induced by cyclosporin A in spontaneous hypertensive rats. Eur J Pharmacol. 2003 Sep 12;477(2):171-8.
The drug has been found as an undeclared adulterant in supposedly "natural" health supplements. In 2009, the supplement manufacturer Hi-Tech Pharmaceuticals recalled its product Stamina-Rx because it was adulterated with benzamidenafil.
See also Acetildenafil Homosildenafil
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