Uncontroversial treatments
PDE5 Inhibitors
The cyclic nucleotide phosphodiesterases constitute a group of enzymes that catalyze the hydrolysis of the cyclic nucleotides cyclic AMP and cyclic GMP. They exist in different molecular forms and are unevenly distributed throughout the body. These multiple forms or subtypes of phosphodiesterase were initially isolated from rat brain by Uzunov and Weiss in 1972 and were soon afterward shown to be selectively inhibited by a variety of drugs in brain and other tissues (Weiss,1975; Fertel and Weiss, 1976). The potential for selective phosphodisterase inhibitors to be used as therapeutic agents was predicted as early as 1977 by Weiss and Hait. This prediction has now come to pass in a variety of fields, one of which is in the pharmacologic treatment of erectile dysfunction
One of the forms of phophodiesterase is termed PDE5. The prescription PDE5 inhibitors sildenafil (Viagra®), vardenafil (Levitra®) and tadalafil (Cialis®) are prescription drugs which are taken orally. They work by blocking the action of PDE5, which causes cGMP to degrade. CGMP specific phosphodiesterase type 5|cGMP]] causes the smooth muscle of the arteries in the penis to relax, allowing the corpus cavernosum to fill with blood.