The most frequent undesirable phenomena are headache and "hot flashes".
Usually, side effects are mild to moderate in use and are transient.
With a fixed dose, the incidence of some adverse events increases with increasing dose.
Side effects are classified according to the following frequency: very often - ≥10%; often - ≥1%,but <10%; infrequently - ≥0,1%, but <1%; rarely - ≥0.01%, but <0.1%; very rarely - <0.01%, the frequency is unknown - it is impossible to determine based on the available data.
From the immune system: infrequently - reactions of hypersensitivity (including skin rash), allergic reactions.
On the part of the blood and lymphatic system: infrequently - anemia, leukopenia.
From the side of metabolism and nutrition: infrequent - thirst, swelling, gout, uncompensated diabetes mellitus, hyperglycemia, peripheral edema, hyperuricemia, hypoglycemia, hypernatremia.
From the nervous system: very often - headache; often - dizziness; infrequently - drowsiness, migraine, ataxia, hypertonus, neuralgia, neuropathy, paresthesia, tremor, vertigo, symptoms of depression, insomnia, unusual dreams, increased reflexes, hypoesthesia; rarely - convulsions *, repeated convulsions *, fainting.
From the side of the cardiovascular system: often - "tides"; infrequent - palpitation, tachycardia, lowering of arterial pressure, unstable angina, atrioventricular blockade, myocardial ischemia, cerebral vascular thrombosis, cardiac arrest, heart failure, deviations in electrocardiogram indications, cardiomyopathy; rarely - atrial fibrillation
From the side of the organ of vision: often - blurred vision, visual impairment, cyanopsy; infrequently - pain in the eyes, photophobia, photopsy, reddening of sclera / injections of sclera, mydriasis, conjunctivitis, eye hemorrhage, cataracts, lacrimation, change in brightness of light perception, chromatopsy; rarely - edema of the eyelids and adjacent tissues, dry eyes, the presence of iridescent circles in the field of view around the light source, increased eye fatigue, vision of objects in yellow light (xanthopsia), vision of objects in red (erythropsy), conjunctival hyperemia, mucosal irritation the shell of the eyes, an unpleasant sensation in the eyes; frequency unknown - non-arteritis anterior ischemic neuropathy of the optic nerve (NPINZN), retinal vein occlusion, defect of the visual fields, diplopia *, temporary loss of vision, increased vigilance, retinal edema, retinal vascular disease, vitreous detachment / vitreous traction.
From the side of the hearing organ: infrequent - sudden decrease or loss of hearing, tinnitus, pain in the ears.
From the respiratory system: often - nasal congestion; infrequently - epistaxis, rhinitis, asthma, dyspnoea, laryngitis, pharyngitis, sinusitis,bronchitis, increased volume of sputum, increased cough; rarely - a feeling of tightness in the throat, dryness of the mucous membrane of the nasal cavity, swelling of the nasal mucosa.
From the gastrointestinal tract: often - nausea, indigestion; infrequent - vomiting, dryness of the oral mucosa, gastroesophageal reflux disease, abdominal pain, glossitis, gingivitis, colitis, dysphagia, gastritis, gastroenteritis, esophagitis, stomatitis, deviation of "liver" functional tests from normal, rectal bleeding; rarely - hypoesthesia of the oral mucosa.
From the side of the musculoskeletal system: often - pain in the back; infrequently - myalgia, pain in the extremities, arthritis, arthrosis, tendon rupture, tenosynovitis, bone pain, myasthenia gravis, synovitis.
From the genitourinary system: infrequently - cystitis, nocturia, enlargement of the mammary glands, urinary incontinence, hematuria, ejaculation disorder, edema of the genitals, anorgasmia, hematospermia, damage to the tissues of the penis; rarely - prolonged erection and / or priapism.
From the skin and subcutaneous tissues: infrequently - skin rash, hives, herpes simplex, pruritus, increased sweating, skin ulceration,contact dermatitis, exfoliative dermatitis; frequency is unknown - Stevens-Johnson syndrome, toxic epidermal necrolysis.
Other: infrequent - a sensation of fever, face swelling, photosensitivity reaction, shock, asthenia, fatigue, pain of different localization, chills, accidental falls, pain in the chest, accidental trauma; rarely - irritability.
* Adverse events identified during post-marketing research.
Cardiovascular complications
During the postmarketing use of sildenafil for the treatment of erectile dysfunction, adverse events such as severe cardiovascular complications (including myocardial infarction, unstable angina, sudden cardiac death, ventricular arrhythmia, hemorrhagic stroke, transient ischemic attack, hypertension and hypotension ), which had a temporary connection with the use of sildenafil. Most of these patients, but not all of them, had risk factors for cardiovascular complications. Many of these adverse events were observed soon after sexual activity, and some of them were noted after taking sildenafil without subsequent sexual activity.
It is not possible to establish the presence of a direct link between the observed undesirable phenomena and these or other factors.
Visual disorders
In rare cases, during the post-marketing use of PDE5 inhibitors, including sildenafil, NPINZN was reported - a rare disease and the reason for the reduction or loss of vision. Most patients had risk factors, in particular, a reduction in the ratio of the diameter of the excavation and the optic disc ("stagnant disk"), age over 50 years, diabetes, hypertension, coronary heart disease, hyperlipidemia and smoking.
In the observational study, it was assessed whether the recent use of PDE5 inhibitors was associated with the acute onset of NPINZN. The results indicate an approximately 2-fold increase in the risk of NPIIV within 5 half-lives after the use of the PDE5 inhibitor. According to the published literature, the annual incidence of NPINZN is 2.5-11.8 cases per 100,000 men aged> 50 years in the general population. It should be recommended to patients in the event of a sudden loss of vision to stop using sildenafil and immediately consult a doctor.Persons who already had a case of NPINZ have an increased risk of recurrence of NPINZN. Therefore, the physician should discuss this risk with such patients, and discuss with them the potential chance of adverse effects of PDE5 inhibitors. PDE5 inhibitors, including sildenafil, these patients should be used with caution and only in situations where the expected benefit outweighs the risk.
When sildenafil was used in doses exceeding recommended, undesirable phenomena were similar to those noted above, but were usually more common.