Erectile dysfunction (ED) is extremely common sexual disorder and said to affect as much as 10 percent of the male population. Above the age of 40, nearly 52 % of men are affected with this sexual disorder. Phosphodiesterase 5 (PDE5) inhibitors are the first line therapy for ED. Before July 2012, only two molecules – sildenafil and tadalafil from this group were available for the treatment of ED in India. Futher, sildenafil has a rapid onset of action but duration of action is shorter while Tadalafil has a longer duration of action but is associated with side effects of muscle pain and back pain. Thus, there was a need for molecule having advantages of the existing agents with better tolerability profile.
Udenafil is a newly developed, potent and selective PDE5 inhibitor approved for treatment of ED. It is a patented molecule developed by M/s Dong-A Pharmaceuticals, Korea. It is the fourth among the PDE5 inhibitors class at the time of approval (first approved in Korea – Dec. 2005). Udenafil has come into Indian Market since July 2012. The unique features of this novel molecule include:
(1) Unique clinical properties of relatively rapid onset and longer duration of action - optimal pharmacokinetic profile - Tmax of 1-1.5 hours and a Half-life of 11-13 hours.
(2) Efficacious in the treatment of ED - broad-spectrum aetiology and severity
(a) There was significant improvement in IIEF, SEP and GAQ parameters in ED patients in the udenafil group in various clinical trials
(b) Efficacious in ED with co morbidities, i.e. Specific studies in ED patients with hypertension (HT)/diabetes mellitus (DM) showed significant improvement in erectile function in ED patients with HT/DM.
(3) Well tolerated –
(a) Udenafil has not been reported for adverse effects on myalgia, back pain and testicular toxicity (Unlike tadalafil). Udenafil does not inhibit PDE11 (>3000 fold selectivity for PDE5 compared to PDE11) unlike tadalafil (5 fold selectivity for PDE5 compared to PDE11).
(b) Incidence of dyspepsia appears to be less
(c) In clinical trials it has been observed that udenafil rarely causes vision related adverse events (blurred vision, eye pain and chromatic vision) with incidence <1 10="" 3="" 400="" a="" affects="" because="" cones="" fold="" for="" has="" ildenafil="" in="" is="" it="" less="" nearly="" only="" patients="" pde6="" probably="" retina="" selective="" selectivity="" span="" vision="">1>
(4) Less lifestyle interactions
(a) Udenafil can be taken without regard to meals (food)
(b) Udenafil does not potentiate the hypotensive effect of alcohol in healthy volunteers
Besides Korea, udenafil was launched subsequently in Russia, Malaysia and Philippines. Udenafil is also approved and marketed in Ukraine, Uzbekistan, Kyrgyzstan and Turkey. The regulatory activities are also ongoing for approval of udenafil in USA.
A randomized, double-blind, placebo controlled, multi-centric, phase III clinical trial was conducted in India which clearly demonstrated that udenafil 100 mg tablets taken as on-demand, 30 minutes to 1 hour before anticipated sexual intercourse was significantly more effective as compared to matching placebo tablets in Indian patients suffering from ED. On the tolerability front, udenafil 100 mg tablets was very well tolerated. Udenafil thus appeared to be a suitable therapeutic modality for the treatment of ED in Indian patients.
A recently published review (Therapeutic Advances in Urology published online 14 December 2012) mentions
ñ Udenafil’s efficacy and tolerability have been evaluated in several studies, and recent and continuing studies have demonstrated udenafil’s promise in both dosing regimens. (on-demand and once-daily)
ñ If some patients wish to receive a long-acting PDE5 inhibitor, but experience side effects with tadalafil, udenafil might be a more appropriate option
ñ The literature reviewed here indicates that udenafil seems to be safe and well tolerated in general ED patients in Korea.
ñ Udenafil seems to be an ideal PDE5 inhibitor, with both short onset time and long duration.
Udenafil may be a reliable treatment option in patients who have relatively spontaneous and unscheduled sexual intercourse.
Indian response to Udenafil is encouraging and leading urologists/andrologists/sexologists across India have started prescribing it. Udenafil is a welcome addition to current management of ED as it assists clinicians in tailoring treatment regimens to the unique needs of each patient with ED.