Study: Viagra, Cialis, Levitra Drugs May Promote Sexual Pleasure

According to a recent study, published at the Journal of Physiology, Sildenafil (Viagra), vardenafil (Levitra) and tadalafil (Cialis) erectile dysfunction drugs may enhance sexual pleasure in addition to their well-known effect on sexual performance.

Viagra (sildenafil), Levitra (vardenafil), and Cialis (tadafil) treat erectile function by enhancing blood flow to the penis. They are classified as sexual stimulants, not aphrodisiacs, in that they improve sexual function but are not known to affect arousal.

However, the researchers indicated that these erectile dysfunction drugs play a key role (indirectly) in regulating release of oxytocin. This may be a key in understanding additional effects that these drugs may have on patient users.

Although the study was made on rats, results seem to show that sildenafil (Viagra) and its analogues seem to stimulate the release of oxytocin. This hormone is released by the neurohypophysis, or posterior pituitary, during orgasm.

Erectile dysfunction (ED or impotence) is a dysfunction characterized by the inability to develop or maintain an erection of the penis. Many underlying causes can be named for ED and many of those causes are medically treatable.

Many "treatments," both medically approved and non-approved, have been suggested for ED. Since the 1930's many folks have taken advantage of a highly devastating psychological sexual condition to push consumer to buy or try different treatments. Options on this are countless. However, the effectiveness of such so-called treatments for ED has not been proved.

Controversial and unapproved treatments include naltrexone, bremelatonine, melanotan II, hMaxiK, Gingseng, Ezyte, herbal treatment, and Prelox.

Cyclic nucleotide phosphodiesterases are a group of chemical compounds that effectively have an effect on ED. One of the forms of phophodiesterase is termed PDE5. The prescription PDE5 inhibitors sildenafil (Viagra), vardenafil (Levitra) and tadalafil (Cialis) are prescription drugs that are taken orally. They work by blocking the action of PDE5, allowing the penis to fill with blood.

The introduction of the first pharmacologically approved drug for ED, sildenafil (trade name Viagra), in the 1990s caused a wave of public attention, helped in part by heavy advertising.

The investigators wrote "Oxytocin also serves as a signal in central neuronal pathways associated with the erectile response".... "If PDE5 inhibitors influence central oxytocin nerve terminals in the same way as peripheral nerve terminals of the posterior pituitary, then the activity of these central oxytocin pathways would be enhanced."

The study suggests that Viagra (sildenafil), Levitra (vardenafil), and Cialis (tadafil) may have other effects (in addition to improve sexual performance), but the experiments were conducted only in animal systems. Further research is needed.

Source:

Zhang Z et al. 2007. Blockade of Phosphodiesterase Type 5 Enhances Rat Neurohypophysial Excitability and Electrically-Evoked Oxytocin Release. J Physiol (E-pub ahead of print) . Abstract URL: http://jp.physoc.org/cgi/content/abstract/jphysiol.2007.139303v1