Sildenafil is a drug that appeared on the pharmaceutical market relatively recently, but managed to win a huge audience of men who have decreased erectile function and, consequently, deterioration or inability to have a full sexual intercourse. Thanks to increased blood flow to the penis, it is possible to solve the problem of insufficient erection literally within 20-30 minutes. Surely every adult has heard the name of such a drug as Viagra. It was the first drug developed on the basis of Sildenafil.
A little bit of history
The founders of Viagra were scientists R. Furhotta, L. Ignarro, and F. Murad. After 20 years of studying the effects of nitric oxide on cells of different tissues, they discovered the principle working with Sildenafil and other drugs. This discovery was so important for medicine that the scientists received the Nobel Prize in 1998.
In 1992, the British company Pfizer tested Sildenafil citrate as a potential treatment for heart disease. Because of its nitric oxide properties, scientists believed that Sildenafil could relax blood vessels and protect the heart. But the hopes were not fulfilled. Sildenafil proved to be useless to the heart muscle. But the drug “worked” in a place no one would have guessed. Many participants confessed that the drug magically increased their erections. Thanks to this accidental discovery, Pfizer went on to explore the substance in a new direction. It ended up changing the lives of millions of people. In 1998, Sildenafil entered the market with approval from the appropriate authorities in the United States.
Pharmacological properties
The mechanism of action of Sildenafil is based on the release of nitric oxide in the corpora cavernosa, which occurs normally before and during sexual intercourse. Nitric oxide activates guanylate cyclase, which triggers processes that lead to relaxation of muscles and increase blood flow to the genitals.
The product belongs to the group of selective inhibitors of tsMF-specific phosphodiesterase 5 (FDE-5), and has a peripheral effect on erection, that is, it specifically increases the effect of nitric oxide on blood flow. Many men who need to take Sildenafil seem to think that by taking one tablet of the drug, you can get a steady erection. In fact, this is not true because Sildenafil only works when you are sexually aroused. By taking a pill and sitting down to watch TV, you will not get an erection.
Pharmacokinetics
Sildenafil is very quickly adsorbed from the gastrointestinal tract, reaching maximum concentrations after 30-120 minutes. Despite the small bioavailability, its rate (43%) is enough to cause the necessary effects. Absorption of the substance decreases with food. Metabolism of Sildenafil occurs with the participation of liver microsomal isoenzymes. Metabolites have an activity of 50% of the activity of the parent substance. The drug has a half-life of up to 6 hours, the main route of excretion is feces and urine.
Indications for use and method of administration
Therapy of problems with full erection during intercourse, i.e. inability to achieve and maintain an erection even when sexually aroused. Sildenafil is available in tablets in different dosages (25, 50, 100 mg).
For the full effect, the drug must be taken an hour before the planned sexual intercourse. It is recommended to start taking it with a dose of 50 mg. Depending on how the therapeutic effect will develop, you may decrease (to 25 mg) or increase (to 100 mg) the dose. Do not exceed a single dose of 100 mg, otherwise there is a high risk of side effects. 100 mg is the maximum daily dose. Time of intake and consumption of food do not matter, but you should remember that taking the drug after eating may delay the onset of action of Sildenafil. Persons of advanced age do not require any dosage adjustment.
Contraindications and side effects
Given its effect on blood flow, Sildenafil has a number of contraindications, including:
- hypersensitivity to Sildenafil or any of the components of the drug;
- use of nitrates in various forms, as Sildenafil potentiates their effects and may increase side effects;
- conditions in which sexual activity is undesirable (cardiovascular failure, angina pectoris);
- visual impairment or complete loss due to ischemic neuropathy of the optic nerve;
- Severe impairment of liver function;
- arterial hypotension;
- Past strokes or heart attacks.
Side effects of the drug should include:
- decreased blood pressure;
- cardiovascular system disorders (ventricular arrhythmia, myocardial infarction, cerebrovascular hemorrhage);
- neurological disorders (dizziness, headache);
- visual and vision disorders;
- possibility of bleeding.
The described side effects are extremely rare, so the drug is often used by men of different ages.
Sildenafil-based medications
Today, there are many Sildenafil-based medications on the market. Some of the most popular include:
- Viagra by Pfizer brand, the drug that started the history of Sildenafil;
- Viagra – generic from well-known Indian pharmaceutical companies, which has proper effects and an affordable price;
- Kamagra – a novelty on the market, which not only has a low cost, but also comes in different forms, for example, as a gel for sublingual use.
What to choose is entirely up to you. All drugs work and have proven their effectiveness.
