Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

A three-part study to investigate the incidence and potential etiologies of tadalafil-associated back pain or myalgia


The potential mechanisms underlying back pain and/or myalgia experienced by men taking tadalafil were investigated. An integrated analysis of 10 placebo-controlled tadalafil clinical trials (N=1846) showed that the incidence of back pain and/or myalgia was 9.4% in patients receiving tadalafil 10 mg (N=394), 8.3% in patients receiving tadalafil 20 mg (N=883) and 3.7% in placebo-treated patients (N=569). One (0.3%) patient receiving tadalafil 10 mg, six (0.7%) patients receiving tadalafil 20 mg, and no patients receiving placebo discontinued treatment due to back pain and/or myalgia. In a prospective study in healthy volunteers, no substantial changes were observed in laboratory markers indicative of inflammation or muscle damage, and tadalafil did not affect renal plasma flow nor produce lumbar or gluteal myositis by positron emission tomography scan or magnetic resonance imaging. Although the mechanism of back pain and/or myalgia remains unknown, these events appear to be self-limiting and a general effect of phosphodiesterase 5 inhibition.

Your institute does not have access to this article

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1


  1. Sadovsky R, Miller T, Moskowitz M, Hackett G . Three-year update of sildenafil citrate (Viagra®) efficacy and safety. Int J Clin Pract 2001; 55: 115–128.

    CAS  PubMed  Google Scholar 

  2. Cheitlin MD et al. Use of sildenafil (Viagra®) in patients with cardiovascular disease. ACC/AHA Expert Consensus Document. J Am Coll Cardiol 1999; 33: 273–282.

    CAS  Article  PubMed  Google Scholar 

  3. Hellstrom WJG et al. Vardenafil for treatment of men with erectile dysfunction: efficacy and safety in a randomized, double-blind, placebo-controlled trial. J Androl 2002; 23: 763–771.

    CAS  PubMed  Google Scholar 

  4. Montorsi F et al. Long-term safety and tolerability of tadalafil in the treatment of erectile dysfunction. Eur Urol 2004; 45: 339–345.

    CAS  Article  PubMed  Google Scholar 

  5. Basu A, Ryder REJ . New treatment options for erectile dysfunction in patients with diabetes mellitus. Drugs 2004; 64: 2667–2688.

    CAS  Article  PubMed  Google Scholar 

  6. Kloner RA . Cardiovascular effects of the 3 phosphodiesterase-5 inhibitors approved for the treatment of erectile dysfunction. Circulation 2004; 110: 3149–3155.

    Article  PubMed  Google Scholar 

  7. Sarazan RD et al. Absence of clinically important HERG channel blockade by three compounds that inhibit phosphodiesterase 5—sildenafil, tadalafil, and vardenafil. Eur J Pharmacol 2004; 502: 163–167.

    CAS  Article  Google Scholar 

  8. Sussman DO . Pharmacokinetics, pharmacodynamics, and efficacy of phosphodiesterase type 5 inhibitors. J Am Osteopathol Assoc 2004; 104: S11–S15.

    Google Scholar 

  9. Seftel AD . Phosphodiesterase type 5 inhibitor differentiation based on selectivity, pharmacokinetic, and efficacy profiles. Clin Cardiol 2004; 27(4 Suppl 1): I14–I19.

    Article  PubMed  Google Scholar 

  10. Cialis (tadalafil) label, 2003 (Ref. Type: Electronic Citation).

  11. Levitra (vardenafil HCl) label, 2003 (Ref Type: Electronic Citation).

  12. Viagra (sildenafil citrate) label, 1998 (Ref Type: Electronic Citation).

  13. Ehrlich GE . Back pain. J Rheumatol Suppl 2003; 67: 26–31.

    PubMed  Google Scholar 

  14. Deyo RA, Weinstein JN . Low back pain. N Engl J Med 2001; 344: 363–370.

    CAS  Article  PubMed  Google Scholar 

  15. Thompson PD, Clarkson P, Karas RH . Statin-associated myopathy. JAMA 2003; 289: 1681–1690.

    CAS  Article  PubMed  Google Scholar 

  16. Zhuang H, Yu JQ, Alavi A . Applications of fluorodeoxyglucose-PET imaging in the detection of infection and inflammation and other benign disorders. Radiol Clin North Am 2005; 43: 121–134.

    Article  PubMed  Google Scholar 

  17. Scott DL, Kingsley GH . Use of imaging to assess patients with muscle disease. Curr Opin Rheumatol 2004; 16: 678–683.

    Article  PubMed  Google Scholar 

  18. Carson CC et al. The efficacy and safety of tadalafil: an update. BJU Int 2004; 93: 1276–1281.

    CAS  Article  PubMed  Google Scholar 

  19. Saenz De Tejada I, Anglin G, Knight JR, Emmick JT . Effects of tadalafil on erectile dysfunction in men with diabetes. Diabetes Care 2002; 25: 2159–2164.

    Article  PubMed  Google Scholar 

  20. Bleeker-Rovers CP et al. Radiolabeled compounds in diagnosis of infectious and inflammatory disease. Curr Pharm Des 2004; 10: 2935–2950.

    CAS  Article  PubMed  Google Scholar 

  21. Manthey N et al. The use of [18F]-fluorodeoxyglucose positron emission tomography to differentiate between synovitis, loosening and infection of hip and knee prostheses. Nucl Med Commun 2002; 23: 645–653.

    CAS  Article  PubMed  Google Scholar 

  22. Russell CD, Taylor AT, Dubovsky EV . Measurement of renal function with technetium-99m-MAG3 in children and adults. J Nucl Med 1996; 37: 588–593.

    CAS  PubMed  Google Scholar 

  23. Fischbach FT, Dunning MB . Immunodiagnostic studies. In: Fischbach FT (ed). A Manual of Laboratory & Diagnostic Tests. Lippincott Williams & Wilkins: Philadelphia, 2003, pp 530–651.

    Google Scholar 

  24. Abramson N, Melton B . Leukocytosis: basics of clinical assessment. Am Fam Physician 2000; 62: 2053–2060.

    CAS  PubMed  Google Scholar 

  25. Brigden ML . Clinical utility of the erythrocyte sedimentation rate. Am Fam Physician 1999; 60: 1443–1450.

    CAS  PubMed  Google Scholar 

  26. Hertzman PA . Criteria for the definition of the eosinophilia–myalgia syndrome. J Rheumatol Suppl 1996; 46: 7–12.

    CAS  PubMed  Google Scholar 

  27. Pasternak RC et al. ACC/AHA/NHLBI clinical advisory on the use and safety of statins. J Am Coll Cardiol 2002; 40: 567–572.

    Article  PubMed  Google Scholar 

  28. Levitra (package insert),, Bayer New Zealand Ltd: Auckland, New Zealand, 2003.

  29. Padma-Nathan H, Giuliano F . Oral drug therapy for erectile dysfunction. Urol Clin North Am 2001; 28: 321–334.

    CAS  Article  PubMed  Google Scholar 

  30. Olsson AM et al. Sildenafil citrate (Viagra®) is effective and well tolerated for treating erectile dysfunction of psychogenic or mixed aetiology. Int J Clin Pract 2000; 54: 561–566.

    CAS  PubMed  Google Scholar 

  31. von Keitz A et al. A multicenter, randomized, double-blind, crossover study to evaluate patient preference between tadalafil and sildenafil. Eur Urol 2004; 45: 499–509.

    CAS  Article  PubMed  Google Scholar 

  32. Morganroth J et al. Evaluation of vardenafil and sildenafil on cardiac repolarization. Am J Cardiol 2004; 93: 1378–1383.

    CAS  Article  PubMed  Google Scholar 

  33. Weeks JL et al. High biochemical selectivity of tadalafil, sildenafil and vardenafil for human phosphodiesterase 5A1 (PDE5) over PDE11A4 suggests the absence of PDE11A4 cross-reaction in patients. Int J Impot Res 2005; 17: 5–9.

    CAS  Article  PubMed  Google Scholar 

Download references


Funding for this and the parent studies was provided by Lilly ICOS LLC. We wish to thank Chris Fischer of ICOS Corporation for his assistance in the preparation of the manuscript.

Author information

Authors and Affiliations


Corresponding author

Correspondence to A D Seftel.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Seftel, A., Farber, J., Fletcher, J. et al. A three-part study to investigate the incidence and potential etiologies of tadalafil-associated back pain or myalgia. Int J Impot Res 17, 455–461 (2005).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • impotence
  • phosphodiesterase inhibitors
  • back pain
  • myositis

Further reading


Quick links