Question Do dietary supplements marketed for the treatment of erectile dysfunction contain phosphodiesterase type 5 inhibitors (such as sildenafil (Viagra) or tadalafil (Cialis))?
Synopsis These investigators purchased seven different brands of dietary supplements for the treatment of erectile dysfunction, six via the internet and one from a local health food specialty store. All products underwent high performance liquid chromatography analyses for the presence of phosphodiesterase type 5 inhibitors. Individuals blinded to product brand names performed the analyses. Two products (Super-X and Stamina-RX) contained significant amounts of sildenafil (Viagra, 30 mg) and tadalafil (Cialis, 20 mg), respectively.
Bottom line At least some natural products marketed for the treatment of erectile dysfunction are adulterated with phosphodiesterase type 5 inhibitors. Many of these products claim to be free of adverse effects but may be fatal to patients concomitantly using nitrates.
Level of evidence 4 (see www.infopoems.com/levels.html). Case series (and poor quality cohort and case-control studies).
Fleshner N, Harvey M, Adomat H, et al. Evidence for contamination of herbal erectile dysfunction products with phosphodiesterase type 5 inhibitors. J Urology 2005;174: 636-41.
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Patient-Oriented Evidence that Matters. See editorial (BMJ 2002;325: 98312411333)