Profiling Sildenafil Citrate: The Magic in Viagra

Sildenafil Citrate is generally known as the active ingredient in the world’s most popular Erectile Dysfunction (ED) drug: Viagra. It was originally developed as a cure for pulmonary arterial hypertension and angina pectoris by a group of pharmaceutical chemists working in Pfizer’s Kent Research facility. Because the drug was discovered not to be effective for angina, but however produced erection among a group of men who were believed to be impotent – surprisingly – Sildenafil Citrate was patented and approved by the United States Food and Drug Administration as the first oral treatment for erectile dysfunction in 1998.

After the normal practice of getting a prescription from the doctor, Viagra pills are typically obtained from reputable pharmacies. However, the proliferation of internet sites offering Viagra tablets for sale – most of them with little or no credible origins – has generally tipped the scales towards the tendency for people to buy Viagra online with no prescription.
What impact has Sildenafil Citrate played since its introduction into the ED market?
Before Viagra pills became available for sale, there were different drugs for the treatment of ED. Available treatment options for Erectile Dysfunction were largely unsatisfactory or inconvenient for use. As early as the 1980s, men suffering from ED were able to inject a drug, commonly Prostaglandin E1, in the corpus cavernosum of their penis (intracorporeal pharmotherapy). Another treatment involved the insertion of a prosthesis into the penis, with the aid of anaesthetics. However, these methods, despite being able to produce erection, were never going to be popular for a number of reasons which all bordered on being not an entirely satisfactory treatment. For instance, the injection of the corpus cavernosum with Prostaglandin E1, if the use is prolonged, could bring about the scarring of the penis. Also, the available drugs then, because there side effects and drug interactions were not well known, were not prescribed by physicians.

Fast forward the late 1990s, 1998 to be specific, the discovery of Sildenafil Citrate or Viagra, as it is more popularly known, did pierce through every existing barrier in the treatment of ED. Not only was the drug convenient for use – due to its amazingly simple oral route of administration – the extensive research carried out by Pfizer, Inc., the manufacturer of Viagra, ensured that who ever wanted to order Viagra tablets, would be doing so equipped with the knowledge of what to expect from its side effects.

The enormous success achieved by Pfizer, Inc., in the marketing of Viagra, to boot, has set a precedence that has concomitantly brought about an increased interest in research and studies on erectile dysfunction by pharmaceutical companies all over the world. These studies, in recent times, have thus far yielded positive results, as new drugs have been added to swell the ranks of drugs available in the ED market.

Explaining the mechanism of action of Sildenafil Citrate.
Sildenafil citrate is a known inhibitor of phosphodiesterase type 5 enzyme (PDE 5). So effective is this drug in inhibiting the enzyme – the enzyme degrades cyclic guanosine monophosphate (cGMP), that relaxes the smooth muscles (vasodilation) when raised in levels – that it exhibits this effect for approximately four hours.

This is possible because Sildenafil, as a structural analogue of cyclic guanosine monophosphate (cGMP), competitively binds with PDE 5, and the raised levels allows for the flow of blood into the corpus cavernosum and subsequent erection of the penis.

Sildenafil citrate, like most medications, produces some minor side effects. These include: stomach ache, dyspepsia, nasal congestion, etc. In addition, sildenafil citrate is contraindicated for some drugs. An example of such drug is the hypertension drugs, typically alpha blockers, which when taken together with Viagra tablets could reduce the blood pressure to a much fatal level.