Sildenafil – Viagra® active ingredient

Sildenafil is used for erectile dysfunction.

Trading names of drugs with active ingredient Sildenafil – Viagra ®, comes in tablet form

Contraindications
Hypersensitivity, treatment with nitrates.

Sildenafil has a peripheral action, selectively inhibiting cGMP-specific phosphodiesterase type 5 (PDE5) which is responsible for the breakdown of cGMP in the cavernous bodies. Physiological mechanism of erection involves the release of nitric oxide in the cavernous bodies of the penis during sexual stimulation. Nitric oxide activates guanylate cyclase, which leads to increased levels of cGMP, relaxation of smooth muscles of the corpora cavernosa and the flow of blood to them. Sildenafil has no direct relaxing effect on smooth muscles of the corpora cavernosa, but by blocking PDE5, and stabilization of cGMP enhances the relaxing effect of nitric oxide.

Sildenafil Restrictions
Sildenafil should not be taken under the deformations of the penis, diseases predisposing to the development of priapism, and increased tendency to bleed, with acute exacerbation of gastric ulcers and duodenal ulcers, with hereditary retinitis pigmentosa, impaired liver function, including with cirrhosis, severe renal failure, severe hypertension and hypotension, history indications transferred in the previous 6 months, myocardial infarction or stroke, life-threatening arrhythmias, heart failure, unstable angina – are also protivopakazaniyami to receive sildenafil.

Side effects of sildenafil

Side effects of sildenafil, taken with the selection of doses that were observed in placebo-controlled trials and marked in ≥ 2% of patients taking sildenafil, with a frequency greater than placebo (in brackets the% of occurrence in the placebo group).
The nervous system and sensory organs: headache 16% (4%), dizziness 2% (1%), flushing 10% (1%), blurred vision (change in color vision, sensitivity to light, blurred vision) 3% (0%).
With the respiratory system: nasal 4% (2%).
From the gastrointestinal tract: Indigestion 7% (2%), diarrhea 3% (1%).
With the genitourinary system: urinary tract infection 3% (2%).
For the skin: Rash 2% (1%).
Other side effects encountered with a comparable frequency (more than 2%) in the group treated with sildenafil and placebo: respiratory infections, back pain, flu-like syndrome, arthralgia.

In studies with a fixed dose of dyspepsia (17%) and blurred vision (11%) occurred more frequently when taking sildenafil 100 mg compared with lower doses. When using doses higher than recommended, we observed similar side effects, but with greater frequency.
Side effects of sildenafil observed in the placebo-controlled trials, and occurs with a frequency of less than 2% (communication with the reception of sildenafil is not clear).
The nervous system and sensory organs: asthenia, dizziness, headache, hypertension, ataxia, tremor, neuralgia, a weakening of reflexes, paresthesia, hypoesthesia, syncope, depression, sleep disturbance (insomnia / drowsiness), conjunctivitis, photophobia, bleeding in the eyeball, mydriasis, cataract, xerophthalmia, pain in eyeballs and ears, tinnitus, deafness.
With the cardiovascular system and blood (hematopoiesis, hemostasis): hypotension, orthostatic hypotension, tachycardia, palpitation, myocardial ischemia, angina, cardiomyopathy, heart failure, ECG changes, including AV-blockade, cardiac arrest, cerebral thrombosis, anemia, leukopenia.
With the respiratory system: pharyngitis, sinusitis, laryngitis, bronchitis, dyspnea, increased number of sputum, increased cough, asthma.
From the gastrointestinal tract: glossitis, gingivitis, stomatitis, dry mouth, dysphagia, esophagitis, nausea, gastritis, gastroenteritis, colitis, rectal bleeding, changes in liver biochemical indices.
From a metabolism: thirst, hypernatremia, gout, hyperuricemia, labile diabetes, hyper-and hypoglycemia.
With the genitourinary system: nocturia, frequent urination, cystitis, incontinence, impaired ejaculation, anorgasmia, genital edema, gynecomastia.
From the musculoskeletal: arthritis, arthrosis, ossalgiya, myalgia, myasthenia, tendon rupture, tenosynovitis, synovitis.
For the skin: urticaria, herpes simplex, pruritus, ulceration of the skin, contact dermatitis, exfoliative dermatitis.
Other: peripheral edema, including facial edema, pain syndromes, including pain in the abdomen and chest, accidental falls, wounds and bruises, sweats, chills, photosensitivity, shock, allergic reactions.

Overdose
Symptoms: a study in healthy volunteers in single dose of 800 mg of sildenafil was observed increased severity of side effects.
Treatment: symptomatic. Dialysis is ineffective because of the high degree of binding of sildenafil and its metabolite to plasma proteins.

Dosing and dose of sildenafil
Sildenafil takes approximately 1 hour before sexual intercourse, 50 mg. Given the efficacy and tolerability the dose may be increased to 100 mg or decreased to 25 mg of sildenafil. The maximum daily dose of 100 mg of sildenafil, the maximum recommended frequency of administration – one time per day.

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