Co-administration of low doses of intranasal PT-141, a melanocortin receptor agonist, and sildenafil to men with erectile dysfunction results in an enhanced erectile response

Urology. 2005 Apr;65(4):755-9. doi: 10.1016/j.urology.2004.10.060.


Objectives: To evaluate the safety and pharmacodynamic effect of co-administration of subtherapeutic doses of PT-141, a cyclic heptapeptide melanocortin analogue, and sildenafil to patients with erectile dysfunction.

Methods: Nineteen patients with erectile dysfunction who were responders to either Viagra or Levitra by self-report were given 25 mg sildenafil and 7.5 mg intranasal PT-141, 25 mg sildenafil and an intranasal placebo spray, and a placebo tablet and an intranasal placebo spray in a randomized cross-over design. Erectile activity in response to two 30-minute episodes of visual sexual stimulation was assessed by RigiScan during a 6-hour postdose period.

Results: The erectile response induced by co-administration of PT-141 and sildenafil was significantly greater than the response elicited by administration of sildenafil alone. Co-administration of PT-141 and sildenafil was safe and well-tolerated and did not result in new adverse events or adverse events that were increased in frequency or severity compared with monotherapy.

Conclusions: Co-administration of intranasal PT-141 and a phosphodiesterase type 5 inhibitor may constitute a treatment alternative for patients in whom higher doses of a single therapy are not effective or well tolerated.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Intranasal
  • Adult
  • Aged
  • Drug Therapy, Combination
  • Erectile Dysfunction / drug therapy*
  • Humans
  • Male
  • Middle Aged
  • Peptides, Cyclic / administration & dosage*
  • Pilot Projects
  • Piperazines / therapeutic use*
  • Purines
  • Remission Induction
  • Sildenafil Citrate
  • Sulfones
  • alpha-MSH


  • Peptides, Cyclic
  • Piperazines
  • Purines
  • Sulfones
  • alpha-MSH
  • bremelanotide
  • Sildenafil Citrate