Long-Term Efficacy of Sildenafil and Tachyphylaxis Effect

Abstract

Our data suggest that there is a possible tachyphylaxis effect with sildenafil. Of the patients who were followed for 2 years 20% had to increase the sildenafil dose to have the same effect and 17% discontinued use due to loss of efficacy.

Sildenafil: A 4-year update in the treatment of 20 million erectile dysfunction patients

“…A recent report by El-Galley et al [38] suggested a possible tachyphylaxis when sildenafil citrate is taken for long periods of time. The authors reviewed a telephone survey of 151 men treated for 1 year with sildenafil.…”

In Vivo Analysis of Chronic Phosphodiesterase-5 Inhibition With Sildenafil in Penile Erectile Tissues: No Tachyphylaxis Effect

“…It has been suggested that tachyphylaxis to this therapy may develop with chronic administration. 9 Many other reports have now shown that PDE5 inhibitor therapy produces durable benefits in men during 2 years of repeat dosing. 10,11 In diabetic rats 3-week gavage with sildenafil increased the maximal electrically induced erectile response, although at the same time it increased PDE5 activity without affecting its protein level.…”

Chronic dosing of phosphodiesterase type 5 inhibitors

“…However, diminished response to these agents resulting in patient dropout occurs with long-term use, with dropout rates greater than 50% in some series [ 17 , 18 ]. Because patients who initially responded in clinical practice began to return and report less effi cacy after prolonged use, El-Galley et al [ 19 ] conducted a telephone survey to document the dropout rate in 200 men taking sildenafi l to treat ED. Of these men, 151 had used sildenafi l over the fi rst year after therapy with a 74% overall improvement rate, defi ned as the ability to initiate and maintain erections for successful intercourse.…”