Viagra is a drug that is used to correct erectile dysfunction in men. The active ingredient is sildenafil.

Pharmacologic effect

Sildenafil belongs to the highly selective inhibitors of cGMP-specific phosphodiesterase type 5. By blocking this enzyme, the substance affects the intensity of blood supply in the genital area.

Physiological erection occurs as a result of the release of nitric oxide in the corpus cavernosum during sexual stimulation. It leads to:

• activation of the enzyme guanylate cyclase;
• increased cGMP levels;
• relaxation of the smooth muscles of the corpus cavernosum;
• increased blood flow to the penis.

Violation of the listed processes at any stage leads to deterioration of erectile function up to impotence. Viagra tablets are used to correct the pathological condition.

Indications for use

The drug is used to treat potency disorders, which manifest themselves as the inability to achieve or maintain a long-lasting, persistent erection required for a quality act of intimacy. The drug should be taken against the background of sexual arousal.

According to official information from the manufacturer, the recommended daily dose is 50 mg. The drug is intended for oral use and must be taken on an empty stomach 40–60 minutes before intended sexual intercourse. Eating the day before will slow down the absorption of the drug and the manifestation of its pharmacological effect.

Side effects and contraindications

Despite its popularity, not all men can take Cialis. Contraindications for use can be absolute or conditional. In the latter case, therapy can be begun, but it must be under constant medical supervision due to the possibility of complications.

Depending on the individual characteristics of the patient, the dosage can be increased to 100 mg or reduced to 25 mg. It is not recommended to use the product more often than once a day.

Contraindications and side effects

The drug is strictly prohibited for use in the following conditions:

You should absolutely not take pills in the following cases:

• Individual hypersensitivity to the active substance or auxiliary components.
• Concomitant use with drugs of the nitrate group which can lead to a sharp drop in blood pressure up to collapse.
• Non-arterial anterior ischemic optic neuropathy, which is accompanied by loss of vision.
• A history of severe somatic diseases (arterial hypotension, liver failure in the stage of decompensation, hereditary degenerative pathologies of the retina, acute myocardial infarction or cerebrovascular accident during the last six months, heart failure in the stage of decompensation).
• Conditions for which sexual activity is not recommended (for example, severe cardiovascular disorders such as unstable angina or severe heart failure).
• Age up to 18 years.

Use simultaneously with antiretroviral drugs and other drugs to correct erectile function.

Prescribing medication with caution to prevent overdose is necessary in the following conditions:

• Elderly age. No dose adjustment is required at the beginning of therapy. However, the drug should be taken under the supervision of a specialist so that if undesirable symptoms occur, the regimen can be changed.
• Severe renal failure. The initial dose of the drug is 25 mg and can be increased to 50 mg or 100 mg after assessing the patient's general condition.
• Severe liver failure. The recommended dose of the drug is 25 mg.
• Concomitant use of antiretroviral drugs, with the exception of ritonavir. The optimal dose is 25 mg.

Many patients with pathology decide to buy Viagra tablets due to their good tolerability and high safety profile. Side effects when taking the medicine are quite rare. The most common reactions include:

• headache, dizziness;
• feeling of hot flashes in the face and neck;
• dyspeptic disorders;
• difficulty in nasal breathing, infrequent nasal bleeding;
• visual disturbances, color vision impairment;
• muscle pain in the spine.

The listed symptoms arise against the background of individual body characteristics and incorrectly selected dosage. To avoid side effects, it is recommended that you use the drug strictly under the supervision of your doctor.

Most, but not all, patients had cardiovascular risk factors. Many of these adverse reactions occurred during or immediately after sexual intercourse, and only a few occurred shortly after using Viagra without sexual activity. Therefore, it is impossible to determine whether the development of such adverse reactions is directly related to risk factors or whether their development is due to other factors.