Udenafil is a novel phosphodiesterase-5 inhibitor approved for use in the country of Korea.
April 10 2016

Andrology. 2013. Efficacy and tolerability of udenafil in Turkish men with erectile dysfunction of psychogenic and organic aetiology: a randomized, double-blind, placebo-controlled study. Udenafil is a potent phosphodiesterase type-5 inhibitor (PDE5) previously shown in studies conducted in populations of Eastern-Asian ethnicity, to significantly improve sexual function, in addition to a favourable safety profile. The purpose of this study was to evaluate the efficacy and safety of udenafil for the treatment of erectile dysfunction (ED), for the first time in a non-Eastern-Asian population. In this multicentre, randomized, double-blind, parallel, placebo-controlled study conducted in five centres in Turkey, 118 eligible subjects were randomized to receive udenafil 100 mg taken as on-demand or matching placebo for an 8-week treatment period. The primary efficacy variable was the change from baseline of the International Index of Erectile Function Questionnaire-Erectile Function Domain (IIEF-EFD) score, secondary efficacy variables were changes from baseline in IIEF Questionnaire Domains' 2-5 scores (Intercourse Satisfaction, Orgasmic Function, Sexual Desire, Overall Sexual Satisfaction) and IIEF Questionnaire Grand Total score, changes from baseline in penetration success rates (SEP2) and intercourse completion rates (SEP3) and evaluation of responses to the global assessment question (GAQ). Patients treated with udenafil demonstrated significantly higher increase in the IIEF-EFD scores compared with placebo-treated subjects and two other IIEF Questionnaire Domains (Domain 4: Sexual Desire, Domain 5: Overall Sexual Satisfaction). The proportion of positive responses to the GAQ was greater in the udenafil compared to the placebo group (72.2% vs. 49.1%, p = 0.014). The most frequent treatment-emergent adverse events were headache, flushing and rhinorrhea, all of mild or moderate severity. This is the first study to demonstrate in a non-Eastern-Asian population that udenafil 100 mg taken as on-demand can effectively improve erectile function and is well tolerated.

J Clin Pharmacol. 2016. The Effect of Age on the Pharmacokinetics of Udenafil in Healthy Subjects. Udenafil, a cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5) inhibitor, has been developed to treat erectile dysfunction. We evaluated the effect of age on the pharmacokinetics and tolerability of udenafil. A single-center, open-label, parallel-group phase 1 study was conducted in healthy adult subjects who took a single oral dose of udenafil (100 mg). The pharmacokinetics and tolerability of udenafil were compared between 12 healthy young males (21-27 years) and 12 healthy elderly males (65-78 years). The clearance and metabolic AUC ratio did not differ between the elderly and young. In terms of tolerability, all adverse events were mild, and all subjects recovered without additional therapy. The systemic exposure of elderly subjects to udenafil appears to be comparable to or slightly less than that of young healthy subjects. Based on our pharmacokinetic comparisons, udenafil dose adjustment is unlikely to be required in the elderly population

Raynaud's disease
Rheumatology (Oxford). December 17 2013. Head-to-head comparison of udenafil vs amlodipine in the treatment of secondary Raynaud's phenomenon: a double-blind, randomized, cross-over study. RP is a reversible vasoconstriction of digital arteries that causes pain and skin discoloration. This study compared the efficacy of the new phosphodiesterase type 5 inhibitor udenafil with that of the calcium channel blocker amlodipine in the treatment of secondary RP.Methods. A total of 29 patients with secondary RP associated with connective tissue diseases were enrolled in this double-blind, randomized, cross-over study. The patients were randomized to receive udenafil 100 mg/day or amlodipine 10 mg/day for 4 weeks. After a washout period they were crossed over to the other drug for another 4 weeks. The primary outcome was RP frequency before and after treatment. The secondary outcomes were RP condition scores, RP duration, number of digital ulcers, HAQ, physician global assessment and digital artery flow before and after treatment.Results. Amlodipine and udenafil both decreased the rate of RP attack significantly. The drugs did not differ in terms of RP frequency or any of the secondary outcomes except for digital blood flow; udenafil improved it significantly better than amlodipine. Udenafil was well tolerated without serious adverse effects.Conclusion. Udenafil and amlodipine have comparable efficacy in improving RP attacks. In addition, udenafil improves the blood flow in digital arteries compared with amlodipine.

Udenafil has unique properties, with a T max of 1.0-1.5 h and a T 1/2 of 11-13 h (a relatively rapid onset and a long duration of action). Therefore, both on-demand and once-daily use have been reported. It's efficacy and tolerability have been evaluated in several studies, and recent and continuing studies have demonstrated udenafil's promise in both dosing regimens. Presently, tadalafil is the only FDA-approved drug for daily dosing, but udenafil can be used as a once-daily dose for erectile dysfunction patients who cannot tolerate tadalafil due to phosphodiesterase subtype selectivity. Udenafil as an on-demand or once-daily dose is effective and tolerable, but more studies are needed in patients of other ethnicities and with comorbid conditions such as diabetes mellitus, hypertension, and benign prostate hyperplasia.