Vardenafil-d₅is intended for use as an internal standard for the quantification of vardenafil by GC- or LC-MS. Vardenafil is a potent inhibitor of phosphodiesterase 5 (PDE5; IC₅₀s = 0.2-1.2 nM) and PDE6 (IC₅₀= 2 nM).^1,2,3It is selective for PDE5 and PDE6 over PDE1 and PDE11 (IC₅₀s = 230 and 130 nM, respectively). Vardenafil (4 mg/kg per day for three weeks) improves erectile function in a rat model of acute arteriogenic erectile dysfunction by increasing intracavernous pressure and mean arterial pressure, and this effect persists for at least two weeks following the end of treatment.⁴Chronic vardenafil administration at a dose of 2 mg/kg for five weeks to subordinate mice reduces the latency to mount and increases the frequency of mounting behavior.⁵Formulations containing vardenafil have been used in the treatment of erectile dysfunction.

1.Card, G.L., England, B.P., Suzuki, Y., et al.Structural basis for the activity of drugs that inhibit phosphodiesterasesStructure12(12)2233-2247(2004) 2.Boyle, C.D., Xu, R., Asberom, T., et al.Optimization of purine based PDE1/PDE5 inhibitors to a potent and selective PDE5 inhibitor for the treatment of male EDBioorg. Med. Chem. Lett.15(9)2365-2369(2005) 3.Smith, W.B., II, McCaslin, I.R., Gokce, A., et al.PDE5 inhibitors: Considerations for preference and long-term adherenceInt. J. Clin. Pract.67(8)768-780(2013) 4.Hotta, Y., Ohno, R., Kataoka, T., et al.Effects of chronic vardenafil treatment persist after end of treatment in rats with acute arteriogenic erectile dysfunctionJ. Sex Med.9(7)1782-1788(2012) 5.Dadomo, H., Parmigiani, S., Nicolini, Y., et al.Repeated and chronic administration of Vardenafil or Sildenafil differentially affects emotional and socio-sexual behavior in miceBehav. Brain Res.253103-112(2013)