Sildenafil Chemical Name: A Drug Akin To White Powder That Has Altered the Medical Scene

In the scientific circles, Sildenafil goes by many names. It is commonly referred to as “PDE-5 inhibitor” but can also go by the IUPAC name 5-[2-ethoxy-5-(4-methyl piperazine-1-yr) sulfonylphenyl]-1-methyl-3-propyl-4H-pyrazolo[4,3-d]pyrimidin-7-one due to its chemical composition. The Molecular Formula of Sildenafil is C22H30N6O4S. The Sildenafil Citrate structure looks thus:

Sildenafil was discovered in England at the Pfizer’s Kent research facility by chemists. They initially looked into it as a treatment for hypertension and heart disease. As they were conducting clinical trials, they found that Sildenafil had an effect on penile erections. It was inducing erections rather than being effective with the intended purpose.

Sildenafil was then marketed by Pfizer as an erectile dysfunction medication in a famous case of drug repositioning

Sildenafil was then marketed by Pfizer as an erectile dysfunction medication in a famous case of drug repositioning. They patented the drug in 1996 and had it approved officially for Erectile dysfunction in 1998 by the FDA. It became the first oral medication used to treat erectile dysfunction in the US. It was a huge commercial success for the company raking in billions annually.

Sildenafil can be used to treat pulmonary arterial hypertension and erectile dysfunction. There have been tests on sexual dysfunction in women but the results have not been conclusive. Sildenafil should not be taken by people with cardiovascular disease because it can result in death at worst.

Sildenafil Citrate Molecular Weight

Sildenafil Citrate has a molecular weight of 666.7. Besides the active ingredient, there are of course other inactive ingredients like anhydrous dibasic calcium phosphate, microcrystalline cellulose, magnesium stearate, croscarmellose sodium, and Triacetin among other components. These also influence the final weight of the tablet.

Sildenafil Citrate Solubility Properties

Sildenafil Citrate is a powder with the white or whitish color. It is crystalline in nature and has a solubility of 3.5 mg/mL. The solvent in this instant is water.

Sildenafil Citrate Melting Point

Sildenafil Citrate melts at 189-190 degrees Celsius according to statistics from DrugsBank. However, according to the Encyclopedia of chemicals, drugs, and biological, the melting point is 187-189 degrees Celsius.

How Sildenafil Citrate Works

Sildenafil works by inhibiting the enzyme PDE-5 in the blood that in turn inhibits cGMP. When the patient is sexually stimulated, the penis is supplied with increased blood flow through the penile arteries. Nitrates are released to enable this process to run smoothly. The patient only has to take a dose of Sildenafil for these effects to take place. For patients who aim to treat other conditions, the principle of operation is merely the same. It is all about relaxing the blood and the muscles to boost the flow of blood to the penis or through the lungs.

The starting dose is usually 50mg. The patient can then observe how he feels after taking 50mg. if they feel like it is too strong, they can reduce the dosage to 25mg. If the dose is too small, they can increase up to 100mg. 100mg is the maximum that they should take within one day.

Sildenafil Citrate Side Effects

When trials were done in the laboratory and they established that there are bound to be some side effects if you use Sildenafil. Some are mild but some are serious and need medical attention. Among the serious side effects are facial flushing, nasal congestion, headache, blurred vision.

There are some cases of patients seeing different colors especially a tinted blue hue. Some people have lost their peripheral vision and complained of blurriness. In the very severe cases, as was brought to the FDA’s attention, the patients suffer from visual impairment.  Some side effects are grave but rare. They include priapism, heart attack, and stroke, hearing loss, low blood pressure and intraocular pressure. Priapism is a condition in which the patient has a prolonged erection. It can be troublesome because it leads to permanent damage to the penile tissues and is considered painful.

In addition to the side effects, Sildenafil interacts with other drugs that the patient is also taking. If the patient is using protease inhibitors like the HIV drugs, they can slow down the uptake of Sildenafil in the body. They also increase the incidence of side effects in patients. This is why you should always consult a doctor before using Sildenafil. People with protease inhibiting medications should not surpass the 25mg mark in 48 hours. Other drugs also tamper with the metabolism of Sildenafil and can adversely affect the body.


Sildenafil is a drug that was discovered in the late nineties that has altered the medical scene. It has changed the way people deal with Erectile dysfunction. Sildenafil is the active ingredients in many ED pills. In addition to ED, Sildenafil handles Pulmonary Arterial Hypertension. PAH and ED are complications that are solved in the same way. Sildenafil relaxes the blood vessels easing the flow of blood to the penis or through the chest.

However, sildenafil should be taken under the watchful eye of a doctor. He can help determine whether sildenafil will react with medication that the patient could be undertaking at the instance of using Sildenafil.

Sildenafil has a complex structure and forms a crystalline powder that is white in color. In addition to that, it is highly soluble in water and has a relatively high melting point. Since it is part of a larger compound, its properties can be slightly different.