International nonproprietary name:...
International nonproprietary name: Sildenafil citrate
Dosage form: tablets, film-coated
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International nonproprietary name: Sildenafil citrate
Dosage form: tablets, film-coated
1 tablet, film-coated, contains:
Sildenafil citrate (equivalent to 25 mg, 50 mg or 100 mg of sildenafil)
microcrystalline cellulose, calcium hydrophosphate, croscarmellose sodium. magnesium stearate, film coating composition: opadray blue OY-LS-20921 (contains hypromellose, lactose, triatsetin, titanium dioxide (E171) and an aluminum lacquer based indigo (E132)) and opadray transparent YS -2-19114-A (contains hypromellose and triatsetin).
Pharmacotherapeutic group : treatment of erectile dysfunction - PDE5 inhibitor
The medication contains the active ingredients Sildenafil - a powerful selective inhibitor of the enzyme called (cGMP)-specific phosphodiesterase 5-th type (PDE5). Physiological mechanism of erection is related to the release of nitric oxide (NO) in the cavernous tissue of the penis during the sexual stimulation. This, in turn, leads to increased levels of cGMP, the subsequent relaxation of the smooth muscles of the cavernous tissue and increase blood flow to the penis. Sildenafil has no direct relaxing effect on isolated human corpus cavernosum, but enhances the effect of nitrogen oxide (NO) by inhibiting PDE5, which is responsible for the breakdown of cGMP.
Sildenafil citrate is selective for PDE5 in vitro, its activity against PDE5 is higher than activity of other known phosphodiesterase enzymes: PDE6 - in 10 times; PDE1 - in more than 80 times; PDE2, PDE4, PDE7-PDE11 - in more than 700 times. Sildenafil in 4000 times is more selective for PDE5 compared with PDE3, which is one of the key enzyme regulating myocardial contractility.
After oral administration, sildenafil citrate is rapidly absorbed. Absolute bioavailability is in average 40% (from 25% to 63%). In vitro sildenafil at a concentration of about 1.7 ng / ml (3.5 nM) inhibits PDE5 rights on 50%. After a single dose of sildenafil 100 mg the average maximum concentration of sildenafil in plasma (Cmax) is about 18 ng / ml (38 nM). Cmax while taking sildenafil on an empty stomach is achieved within an average of 60 minutes (from 30 min to 120 min). When brand Sildenafil tabs taken in combination with fatty food the rate of absorption is reduced: Cmax is decreased by an average of 29%, and the time of maximal concentration (Tmax) is increased up to 60 minutes.
The volume of distribution of sildenafil at steady state is in average 105 liters.
The connection of sildenafil and its main circulating metabolite- N-dimethyl with plasma proteins is about 96% and does not depend on the total concentration of the drug. Less than 0.0002% of the dose of sildenafil (in average 188 ng) detected in sperm after 90 minutes after ingestion.
Sildenafil is metabolized primarily in the liver under the action of cytochrome isoenzyme CYP3A4 (major route) and the enzyme cytochrome CYP2C9 (minor route). The main circulating active metabolite is N-demethyl- sildenafil. The selectivity of action of this metabolite on PDE5 is similar to sildenafil, and its activity against PDE5 in vitro is about 50% of the activity of sildenafil citrate. Concentration of metabolite in the blood plasma of healthy volunteers was about 40% of the concentration of sildenafil. N-dimethyl metabolite is undergone a further metabolism, during its half-life (T1 / 2) which is about 4 hours.
The total clearance of sildenafil is 41 l / h, and the final T1 / 2 - 3-5 hours. After oral administration, as well as after intravenous administration of sildenafil is excreted as metabolites, mainly with faeces (about 80% of oral dose) the kidneys (about 13% of oral dose).
Sildenafil is contraindicated in the following conditions:
Hypersensitivity to sildenafil citrate or any other components of the drug.
Concomitant application of nitrates or nitrogen oxide donors (see Sildenafil drug interaction)
The safety and effectiveness of the Sildenafil citrate tablets in combination with other erectile dysfunction drugs was not studied. The use of such combinations is not recommended.
The medication is not intended for use in children under 18 years
Sildenafil is not intended for use in women
Sildenafil original should be used with caution in:
An anatomical deformity of the penis (angulation, cavernous fibrosis or Peyronie's disease)
Diseases predisposing to the development of priapism (sickle-cell anemia, multiple myeloma, leukemia, thrombocytemia)
Diseases associated with bleedings
Aggravation of stomach or duodenal ulcers
Hereditary retinitis pigmentosa
Heart failure, unstable angina, myocardial infarction, stroke or life-threatening arrhythmia, hypertension (blood pressure> 170/100 mmHg. Cent.) or hypotension (BP <90/50 mmHg)
Sildenafil Pregnancy and lactation
According to the registered indication the drug is not intended for use in women
Sildenafil Dosing and Administration
Sildenafil original tablets are taken orally.
The recommended dose for the most adults is 50 mg nearly 1 hour before sexual activity. Sildenafil dose may be increased up to 100 mg or decreased up to 25 mg. The maximum recommended dose is 100 mg. The maximum recommended frequency of application - once a day.
In mild and moderate degree of renal insufficiency (CC 30-80 ml / min), the dosage adjustment is not required, in severe renal insufficiency (CC <30 ml / min) - dose of sildenafil should be reduced to 25 mg.
Dose of the Sildenafil should be reduced to 25 mg.
Combined use with other drugs
In a concomitant application with ritonavir maximum single dose of the drug Sildenafil ® should not exceed 25 mg, and the frequency of application - 1 time in 48 hours.
In concomitant application with inhibitors of cytochrome isoenzyme CYP3A4 (erythromycin, saquinavir, ketoconazole, itraconazole) initial dose of the drug Sildenafil ® should be 25 mg. To minimize the risk of postural hypotension in patients which take alpha-blockers, Sildenafil® application should be started only after achieving stabilization of hemodynamics in these patients.
Adjustment of the dose Sildenafil® is not required.
Sildenafil side effects
Sildenafil is usually well tolerated and Sildenafil side effects are not common. Sildenafil side effects have been studied in more than 3700 men suffering from erectile dysfunction. According to the statistics the most observed Sildenafilcitrate side effects include: headache (in 16%), hot flashes (facial flushing in more than 10%), stomach problems (dyspepsia), rhinitis (nasal congestion) in more than 4%, infections of the urogenital system also known as UTI infections (in 3% of patients), vision disorders (blurred vision, changes in vision color, increased sensitivity to light), diarrhea (in nearly 3% of patients), dizziness and skin rash (in nearly 2% of patients).
Other Sildenafil side effects were reported in less than 1% of patients. These Sildenafil side effects may include: infection of the upper or lower airways, joint pain, back pain, cold and flu symptoms like fever, cough, rhinitis, and headache.
When Sildenafil brand is used in high doses the medication may cause the following side effects:
In very rare cases Sildenafil may cause the following side effects: urinary incontinence, asthma, insomnia, agitation, fear, depression, priapism, arthritis, gout, muscle pain, anemia, dry mouth, vomiting, angina pectoris, migraine, temporary vision less.
The relation of Sildenafil with cardiovascular complications such as strokes, heart attacks is not established.
Sildenafil drug interactions
Make sure to inform your health care provider about all medications you are currently using. These interactions may include over-the-counter, prescription drugs, herbal supplements, vitamins. Brand Sildenafil citrate tablets may interact with the following medications:
Nitrates or nitrogen oxide donors like nitroglycerin. Their combination may lead to a life-threatening drop in blood pressure.
H2 histamine receptor blockers (cimetidine)- this medication can significantly decrease the elimination of Sildenafil out of the organism. This can increase blood levels of Sildenafil citrate.
Antivirals like HIV treatment medicines: ritonavir (protease inhibitors)- )- this medication can significantly decrease the elimination of Sildenafil citrate out of the organism. This can increase blood levels of Sildenafil.
Blood pressure medication - calcium channel blockers (Amlodipine known under the brand name Norvasc)- patients taking this combination may cause significantly decrease blood pressure.
Alpha blockers which (some of them are used for BPH) - patients taking this combination may cause significantly decrease blood pressure.
Macrolide antibiotics (erythromycin)- the medication may slow down Sildenafil metabolism leading to increased blood levels of Sildenafil.
Antifungal agents (like Fluconazole, Ketoconazole)- the metabolism and elimination of Sildenafil can be reduced. This may increase the chance for Sildenafil side effects.
Original Sildenafil special cautions
For the diagnosis of erectile dysfunction, determine its possible causes and select appropriate treatment is necessary to collect a complete medical history pass all necessary physical examinations.
Sexual activity is a risk if patients suffer from cardiovascular diseases, so before beginning any erectile dysfunction therapy a doctor should check the functional condition of the patient's cardiovascular system. Sexual activity is not desirable in patients with heart failure, unstable angina, myocardial infarction or stroke, life-threatening arrhythmias, arterial hypertension (blood pressure> 170/100 mmHg. or hypotension (BP <90/50 mm Hg). Clinical studies showed no difference in the incidence of myocardial infarction (1.1 per 100 person-years) or the frequency of deaths from cardiovascular disease (0.3 per 100 person-years) in patients receiving the drug Sildenafil®, in comparison with patients who received placebo.
Preparations intended for the treatment of erectile dysfunction, should not be given to men for whom sexual activity is undesirable.
Sildenafil brand has systemic vasodilating effects, resulting in a transient reduction of blood pressure, which is not a clinically significant phenomenon and does not lead to any consequences in most patients. Nevertheless, drug Sildenafil ® physician before prescribing Sildenafil should carefully estimates the risk of possible vasodilating action in patients with relevant diseases. Increased sensitivity to the vasodilator observed in patients with aortic stenosis, hypertrophic obstructive cardiomyopathy), as well as the rarely occurring syndrome of multiple system atrophy, manifested severe disturbance of the regulation of blood pressure by the autonomic nervous system.
In some patients Sildenafil 100mg original may cause ischemic optical neuropathy. Most of these patients had risk factors such as the excavation (deepening) of the optic nerve head, age over 50 years, diabetes mellitus, hypertension, ischemic heart disease (IHD), hyperlipidemia and smoking. The physician should inform the patient about the increased risk of anterior ischemic optic neuropathy. Since the combined use of Sildenafil and alpha-blockers can lead to symptomatic hypotension in some sensitive patients, the drug Sildenafil ® should be carefully used in patients receiving alpha-blockers (see "Interaction with other drugs"). To minimize the risk of postural hypotension in patients taking beta-blockers, taking the drug Sildenafil® should be started only after achieving stabilization of hemodynamics in these patients. The physician should inform patients about what action should be taken in case of symptoms of postural hypotension.
A small number of patients with hereditary retinitis pigmentosa have genetically determined dysfunction of phosphodiesterases retina. The information about the safety of Sildenafil® in patients with retinitis pigmentosa is absent, so sildenafil should be used with caution in this condition.
Sildenafil enhances anti aggregation effect of sodium nitroprusside (nitric oxide donator) on human platelets in vitro. For information about the safety of the drug Sildenafil® in patients with internal bleeding or active peptic ulcer of the stomach are not available, so it should be used with caution.
Sildenafil should be used with caution in patients with anatomical deformation of the penis (angulation, cavernous fibrosis, Peyronie's disease), or in patients with risk factors for priapism (sickle cell anemia, multiple myeloma, leukemia)
Safety and effectiveness of Sildenafil with other agents in the treatment of erection disorders were not studied, so the use of such combinations is not recommended.
In some post-marketing and clinical studies with the use of all PDE5 inhibitors, including sildenafil, reported a sudden decrease or loss of hearing. However, most of these patients had risk factors for this pathology, and there were no correlation between the use of PDE5 inhibitors and sudden decrease or loss of hearing.
While taking sildenafil any negative impact on driving ability or other technical means were not observed. However, because while taking sildenafil may reduce blood pressure, the development of blurred vision Sildenafil tabs should be used with caution