Re: The Efficacy and Safety of Udenafil, a New Selective Phosphodiesterase Type 5 Inhibitor, in Patients with Erectile Dysfunction

By: Konstantinos Hatzimouratidis

European Urology, Volume 54 Issue 4, October 2008, Pages 946-947

Published online: 01 October 2008

Abstract Full Text Full Text PDF (98 KB)

Paick J-S, Kim SW, Yang DY, Kim JJ, Lee SW, Ahn TY, Choi HK, Suh J-K, Kim SC
J Sex Med 2008;5:946–953
Expert's summary:
This is the first full text report on efficacy and safety of udenafil, a new phosphodiesterase type 5 inhibitor (PDE5i). It follows the typical design of multicenter, double-blind, placebo-controlled, fixed-dose, parallel-group study. A total of 167 patients with erectile dysfunction (ED) of diverse origin and severity were randomized to take placebo or udenafil at fixed doses of 100 or 200 mg as needed for 12 weeks.

Both active drug doses improved significantly the erectile function domain scores of the International Index of Erectile Dysfunction (IIEF) questionnaire as well as questions 3 and 4 of IIEF. The ability for successful vaginal penetration and the ability to maintain an erection for successful intercourse (assessed by questions 2 and 3 of the Sexual Encounter Profile–SEP, respectively) and the overall improvement of erections (assessed by the Global Assessment Question - GAQ) improved also significantly. Success rates–based on SEP3–were 70% and 75.7% in the 100mg and 200mg udenafil group, respectively. Udenafil's safety profile is similar to other PDE5i with flushing, headache, nasal congestion and ocular hyperemia being the most common (23.2%, 8.9%, 7.1% and 7.1% in the 200mg group, respectively). There were no significant differences in terms of efficacy between the two udenafil groups. However, adverse events were almost double in the 200 mg group.

Although the study group is a typical ED group, there are no data on efficacy stratified by ED severity or normalization of erections (IIEF ≥26) after treatment. However, such data are to be expected in future studies.
Expert's comments:
Another PDE5i? Udenafil is a new drug in this class, 5 years after tadalafil and vardenafil. Not surprisingly, udenafil seems to offer comparable efficacy and safety to the three currently available PDE5i. Does it offer anything new or it is simply a treatment alternative? Udenafil has a different pharmacokinetic profile. Tmax is about 1–1.5 hours and T1/2 is about 11–13 hours. Therefore, udenafil has a relatively rapid onset of action (like sildenafil and vardenafil) and a long duration (but not as long as tadalafil). Furthermore, it does not inhibit PDE11 like tadalafil and it is not associated with visual disturbances or myalgia (like sildenafil–vardenafil and tadalafil, respectively).

Despite favourable efficacy and safety profile of PDE5i about 50% of patients discontinue treatment [1]. Patients’ needs and expectations vary widely. The treatment approach should always be individualised according to their preference for information and involvement in the decision-making process [2]. Patient satisfaction is a complex issue that depends not only on therapeutic outcomes in terms of efficacy and adverse events or complications but also on expectations from treatment and relationship dynamics [3].

How does udenafil fit in this setting? Due to the aforementioned differences, it is not just another treatment option but it may enable better selection of treatment according to patient's sexual life profiles. Udenafil has just started its journey in the field of ED. Other PDE5i are coming (like avanafil and mirodenafil [4]). There is no doupt that new data on udenafil will be presented in the short future following the example of older PDE5i. Clinicians must not forget that a patient-centered approach is necessary for the management of ED [5]. The management strategy must be supplemented by a careful follow-up in order to identify changes in patients’ expectations and possible side effects that may need treatment optimization. This is the only way to increase efficacy and safety of current and future treatments, as well as patients’ adherence, with certain benefits not only for our patients, but also for the healthcare systems, especially in terms of cost-effectiveness.
Conflicts of interest: The authors have nothing to disclose.


  • [1] M.L. Gonzalgo, M. Brotzman, B.J. Trock, A.M. Geringer, A.L. Burnett, J.P. Jarow. Clinical efficacy of sildenafil citrate and predictors of long-term response. J Urol. 2003;170:503-506 Crossref
  • [2] I. Gruenwald, O. Shenfeld, J. Chen, et al. Positive effect of counseling and dose adjustment in patients with erectile dysfunction who failed treatment with sildenafil. Eur Urol. 2006;50:134-140 Crossref
  • [3] S.E. Althof. When an erection alone is not enough: biopsychosocial obstacles to lovemaking. Int J Impot Res. 2002;14(Suppl 1):S99-S104 Crossref
  • [4] K. Hatzimouratidis, D.G. Hatzichristou. Looking to the future for erectile dysfunction therapies. Drugs. 2008;68:231-250 Crossref
  • [5] L. Athanasiadis, S. Papaharitou, G. Salpiggidis, Z. Tsimtsiou, E. Nakopoulou, P.S. Kirana, et al. Educating physicians to treat erectile dysfunction patients: development and evaluation of a course on communication and management strategies. J Sex Med. 2006;3:47-55 Crossref


2nd Department of Urology and Center for Sexual and Reproductive Health, Aristotle University of Thessaloniki, Greece

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