Erectile dysfunction is the inability to get or keep an erection which is hard enough for sexual intercourse. Erectile dysfunction is also sometimes referred to as male impotence.

A review of a decade of articles concerning the three PDE-5 treatment options for erectile dysfunction Sildenafil (Viagra), Tadalafil (Cialis), and Vardenafil (Levitra) reveals that men consistently prefer one medication over the other two choices. Despite research showing no significant differences in the three drugs’ safety and efficacy, men have a preference for Cialis (tadalafil).

Research indicates that the three current PDE-5 (phosphodiesterase type 5) inhibitors on the market have no significant differences regarding safety and efficacy. The medications do differ, however, in their half-life (how long it takes for the drug to lose 50% of its potency) and the impact of diet on absorption.

Levitra and Viagra take effect in about half an hour. The effects of Levitra last for around five hours, while Viagra lasts for around four hours. Cialis works within about 15 minutes, and the effects last up to 36 hours.

All three drugs are PDE-5 inhibitors, but they also affect other PDE enzymes. For example, Viagra and Levitra inhibit PDE-6, which is found in the eye, more than Cialis does. Some users of Viagra report seeing a bluish cast and experiencing greater light sensitivity. Levitra and Viagra also inhibit PDE-1 more than Cialis does. PDE-1 is found in the heart, brain, and vascular smooth muscle. This results in flushing and rapid heart rate more often in men who take Levitra and Viagra than in men taking Cialis.

However, Cialis inhibits PDE-11 more than Levitra and Viagra do. PDE-11 is found in skeletal muscles, the liver, kidney, pituitary gland, prostate, and testes. The bodily effects of PDE-11 inhibition are not fully known at this time.

Men’s preference when choosing treatment depends on three things: personal characteristics (e.g., age, how long they have had erectile dysfunction, and the state of their sexual relations), their partners’ characteristics (e.g., age, menopausal status, level of interest in sexual activity), and the treatment’s features, such as quality of erection, consistency of results, how long it takes for an erection to occur, side effects, convenience, cost, and how the treatment is administered.