The promising clinical data for the first orally active phosphodiesterase inhibitor, sildenafil (Viagra), for treating male erectile dysfunction (ED) boosted research activities into the physiology of the erectile mechanism. Peripheral intracellular signal transduction in the penis as well as central brain and spinal cord pathways controlling penile erection have been researched. The results provided the basis for the development and introduction of several new therapeutic modalities into the management of ED. Because the concept of taking a pill to cure an illness or relieve symptoms of a disease has become widely accepted by consumers, the pharmacological treatment of ED has primarily focused on selective, orally available drugs that act by influencing intracellular or central regulatory mechanisms, combining a high response rate and the advantage of an on-demand intake. Compared with sildenafil, these agents are regarded more efficacious, have a faster onset of drug action in the target tissue and an improved effect to side effect ratio. This review describes the major new and evolving pharmacological advances in the field of oral pharmacotherapy for the treatment of male ED.
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