PubMed | Google ScholarSee all References This prolonged excretion half-life produces enhanced erections up to 36 hours after oral dosing, thereby potentially allowing for more spontaneous engagement of intercourse. The efficacy of tadalafil in the treatment of ED has been proved in randomized double-blind, placebo-controlled trials.78x78Porst, H, Padma-Nathan, H, Giuliano, F, Anglin, G, Varanese, L, and Rosen, R. Efficacy of tadalafil for the treatment of erectile dysfunction at 24 and 36 hours after dosing: a randomized controlled trial. Urology. 2003; 62: 121–125
Following the breakthrough in ED treatment using PDE5-inhibitors, Western medicine has now moved on to a new frontier of regenerative medicine, with stem cell and gene therapy leading the way (25). There is a practical need for novel therapy as a significant portion of diabetic or post-prostatectomy ED patients do not respond to oral pharmacotherapy. To date, stem cells derived from different sites including adipose tissue-derived stem cells, bone marrow mesenchymal stem cells and muscle-derived stem cells have been investigated using animal models for ED, to study their effects on neural, vascular, endothelial or smooth muscle regeneration (25,26).
Older age. A man’s risk increases past the age of 40, as age is the variable most strongly associated with impotence. This is due to changing hormones, higher risk for heart problems and those affecting circulation, and decreased sexual desire that often occurs with increasing age. For example, based on findings from the National Health and Social Life Survey, it’s been found that “men between 50–60 years old are more than 3 times as likely to experience erection problems and to report low sexual desire compared to men aged 18 to 29 years.” (3)
PDE-5 inhibitors amplify the intacavernosal production of cGMP in response to nitric oxide. This is achieved through the inhibition of cGMP's breakdown by the enzyme, PDE-5. If the predominant abnormality in the individual EDDM patient is molecular, the higher tissue levels of cGMP will overcome these inhibitory factors and the patient will regain erectile function. If the physical structure (eg, the compliance) of the cavernosal tissue has been significantly compromised by apoptosis of smooth muscle or increased collagen deposits, restoration of erectile function will not be achieved. These structural changes explain the lower efficacy rates of PDE-5 inhibitors in EDDM than in the general population.
Since 1998, when sildenafil (brand name Viagra) first came on the market, oral therapy has been successfully used to treat erectile dysfunction in many men with diabetes. (Sildenafil was followed in 2003 by the drugs tadalafil [Cialis], vardenafil [Levitra] and avanafil [Stendra], which work in much the same way.) Some 50% of men with Type 1 diabetes who try the drugs report improved erections, and some 60% men with Type 2 diabetes do, too. However, that leaves a large percentage of men with diabetes and erectile dysfunction who do not respond to therapy with one of these pills. This article takes a look at what can be done to treat those men who do not respond to oral therapy.