What is Sildenafil?

Sildenafil (Sildenafil Citrate) is a substance that helps to induce and maintain male erection. It increases blood flow to the penis and fills the cavernous bodies with blood. Sildenafil is widely used for erectile dysfunction.

How does Sildenafil Citrate work?

In our body, there is an enzyme cGMP-specific phosphodiesterase type 5 or PDE-5. Its main role is to prevent muscle relaxation. When the muscles are tense, the vessels are narrow and circulation is poor.

PDE-5 is found in large concentration in the penis.

Sildenafil Citrate is a PDE-5 inhibitor which means that it inhibits the action of PDE-5 relaxing the smooth muscles, widening the vessels and increasing blood flow.

Sildenafil interaction with other drugs. Side effects

Before taking Sildenafil, consult your doctor and notify him or her about other drugs you are taking and about your current conditions.

Do not take Sildenafil if you are already taking nitrate drugs and recreational drugs such as “poppers” as it can cause a sudden and serious drop in blood pressure.

Grapefruit or grapefruit juice may interact with Sildenafil and lead to unwanted side effects.

The following side effects may occur after taking Sildenafil:

  • Common: runny and stuffy nose, insomnia, headache.
  • Rare: nosebleed, low blood pressure, muscle pain, backache, indigestion.
  • Very rare: painful erection that lasts more than 4 hours.
  • In exceptional cases: as a result of decreased blood flow to the optical nerves, temporary sudden loss of vision may occur. People with diabetes, suffering from cardiovascular diseases and high cholesterol, having vision disorders are in a group of risk.

Sildenafil dosage and use

The recommended starting dose of Sildenafil for most of the patients is 50 mg. It can be changed depending on the individual efficacy. If the effect is not good enough, the dose may be increased to 100 mg. If you need to minimize side effects, the dose is reduced to 25 mg. The maximum dose is 100 mg. It is not recommended to take Sildenafil more than once a day.

Take Sildenafil at least an hour before your sexual activity. This drug has shown to improve erectile dysfunction from 30 minutes and up to 4 hours after you take it.

Sildenafil can be taken with or without food.

Erection is not induced by the drug but occurs only with sexual stimulation.

Sildenafil generics

Generic is a medication manufactured by the company B using the active substance developed by the company A.

A drug developer spends a lot of time and money on research and development. It conducts laboratory and clinical studies and numerous safety tests. If the substance shows good efficacy and safety, it is used to develop a new drug which is introduced to the market.

The drug developer obtains a patent that gives it an exclusive right to manufacture and sell the drug. No other company can manufacture drugs with the substance that was developed by some other company.


Generics can be manufactured only when the patent expires.

Sildenafil Citrate is an active substance developed by Pfizer. The brand name of the drug is Viagra. The patent for Viagra is in force until 2020.

Actually, there is Viagra generic manufactured by Teva under the authorization of Pfizer.

As for illegal generics of Viagra, they are manufactured mostly in developing countries, for example, in India. From these markets they make their way to the markets in Europe, the USA and Canada. Unlike generics of Teva, illegal generics are never tested and studied.

Why are they so popular then? First, they are cheap. Second, original Viagra is available only with a doctor’s prescription.  Not all men can confess that they have erection problems. They prefer to buy online without a prescription.