Viagra

Viagra is a drug that provokes a significant increase in erection and time of sexual intercourse. The drug begins to work approximately 30 minutes after application. The erection persists for 4-5 hours.

Indications

This drug is aplied for the treatment of erectile dysfunction that is characterized by the inability to achieve or keep an erection sufficient for sexual intercourse. Sildenafil is only effective with sexual stimulation.

Dosage and mode of application

Route of administration: Oral. It can be taken with or without water. The tablet should be taken immediately after opening the blister. The daily recommende dosage is 50 mg. If the effect is unsaisfactory, the dose can be increased up to 100 mg. If the effect is increased, use 25 mg of sildenafil.

The maximum recommended frequency of use is 1 time per day. Keep in mind that the absorption of sildenafil is significantly slowed down when used in combination with fatty foods.

Contraindications

Hypersensitivity to sildenafil or any excipients;
Usage in patients taking continuously or intermittently donors of nitric oxide, organic nitrates or nitrites in any form, since sildenafil enhances the hypotensive effect of nitrates;
Combined usage of PDE-5 inhibitors, including sildenafil, with guanylate cyclase stimulants such as riociguat; this can result in symptomatic hypotension;
Combined usage with other drugs for the treatment of erectile dysfunction;
Lactose intolerance, lactase deficiency, glucose-hapactose malabsorption;
Severe hepatic impairment;
Combined use of ritonavir;
Severe cardiovascular diseases (severe heart failure, unstable angina pectoris, stroke or myocardial infarction within the last 6 months, life-threatening arrhythmias, hypertension (BP> 170/100 mm Hg) or arterial hypotension (BP <90/50 mm Hg);
Patients with episodes of development of non-arteritic anterior ischemic neuropathy of the optic nerve with loss of vision in one eye;
Hereditary retinitis pigmentosa;
Not intended for use in women;
According to a registered indication, it is not intended for use in children under 18 years of age.

Side effects

The immune system: infrequently – hypersensitivity reactions (including skin rash), allergic reactions.
The organ of vision: often – blurred vision, cyanopsia; infrequently – eye pain, photophobia, photopsia, chromatopsia, eye redness/sclera injections, changes in the brightness of light perception, mydriasis, conjunctivitis, hemorrhage in the eye tissue, cataracts, disruption of the lacrimal apparatus; rarely – swelling of the eyelids and adjacent tissues, a feeling of dryness in the eyes, increased eye fatigue, xanthopsia, erythropsia, conjunctival hyperemia, mucosal irritation membranes of the eyes, discomfort in the eyes; frequency unknown – retinal vein occlusion, visual field defect, diplopia, temporary loss of vision or decreased visual acuity, retinal edema, retinal vascular disease, vitreous detachment/vitreous traction.
The organ of hearing: infrequently – a sudden decrease or loss of hearing, tinnitus, ear pain.
The cardiovascular system: often – hot flashes; infrequently – tachycardia, palpitations, decreased blood pressure, increased heart rate, unstable angina pectoris, AV blockade, myocardial infarction, cerebral vascular thrombosis, cardiac arrest, heart failure, abnormal ECG readings, cardiomyopathy; rarely – atrial fibrillation, sudden cardiac death, ventricular arrhythmia.
The blood and lymphatic system: infrequently – anemia, leukopenia.
The side of metabolism and nutrition: infrequently – a feeling of thirst, edema, gout, uncompensated diabetes mellitus, hyperglycemia, peripheral edema, hyperuricemia, hypoglycemia, hypernatremia.
The respiratory system: often – nasal congestion; infrequently – epistaxis, rhinitis, asthma, dyspnoea, laryngitis, pharyngitis, sinusitis, bronchitis, increased sputum volume, increased cough; rarely – a feeling of tightness in the throat, dryness of the nasal mucosa, edema of the nasal mucosa.
The gastrointestinal tract: often – nausea, dyspepsia; infrequently – GERD, vomiting, abdominal pain, dryness of the oral mucosa, glossitis, gingivitis, colitis, dysphagia, gastritis, gastroenteritis, esophagitis, stomatitis, abnormal liver function tests, rectal bleeding; rarely – hypesthesia of the oral mucosa.
The musculoskeletal system: often – back pain; infrequently – myalgia, pain in the extremities, arthritis, arthrosis, tendon rupture, tenosynovitis, bone pain, myasthenia gravis, synovitis.
The genitourinary system: infrequently – cystitis, nocturia, enlargement of the mammary glands, urinary incontinence, hematuria, ejaculation disorders, edema of the genitals, anorgasmia, hematospermia, damage to the tissues of the penis; rarely, prolonged erection and/or priapism.
The central and peripheral nervous system: very often – headache; often – dizziness; infrequently – drowsiness, migraine, ataxia, hypertonicity, neuralgia, neuropathy, paresthesia, tremor, vertigo, symptoms of depression, insomnia, unusual dreams, increased reflexes, hypesthesia; rarely – convulsions, repeated convulsions, fainting.
The skin and subcutaneous tissues: infrequently – skin rash, urticaria, herpes simplex, itchy skin, increased sweating, skin ulceration, contact dermatitis, exfoliative dermatitis; frequency unknown – Stevens-Johnson syndrome, toxic epidermal necrolysis.
Others: infrequently – a feeling of heat, face swelling, photosensitivity reaction, shock, asthenia, fatigue, pain of various localization, chills, accidental falls, chest pain, accidental trauma; rarely – irritability.

Overdose

Symptoms: a single dose of Viagra at a dose of up to 800 mg causes the same adverse events as when taking the drug at lower doses. The use of a dose of 200 mg did not result in an increase in the drug effectiveness, however, the frequency of adverse reactions (headache, hot flashes, dizziness, dyspepsia, nasal congestion, visual impairment) increased.

Treatment: symptomatic. Hemodialysis does not accelerate sildenafil clearance, because the latter actively binds to plasma proteins and is not excreted by the kidneys.