Which is better - tadalafil or sildenafil. Medicinal reference geotar Madness precio de sildenafil tablets

By far the most effective method The use of drugs - PDE-5 inhibitors - is recognized for the treatment of erectile dysfunction. The first invented remedy from this group was sildenafil, price which today depends on whether the tablet is original or an analogue. The medicine is better known as Viagra and since its appearance on the pharmaceutical market 2 more have been released effective means- tadalafil and vardenafil, buy which are available in our pharmacy.

Comparison of Sildenafil, Vardenafil and Tadalafil

The mechanism of action of the drugs is almost identical. After taking the pill and sexual stimulation, special nerve impulses are activated and nitric oxide is released. Then, cyclic guanosine monophosphate accumulates in vascular smooth muscle cells. Thanks to it, a chain of biochemical reactions is launched, the result of which is the appearance of an erection.

Despite the same effect of the drugs, they have a number of differences.

Generic Viagra

1. Duration of action. Viagra- Sildenafil, buy which you can in our pharmacy, and vardenafil continue to act for 5 hours, and tadalafil for 36. Therefore tadalafil (price which is indicated in the corresponding section of the site) is popular among those couples who seek to restore natural sexual relationships.

2. Chemical structure. Similar chemical composition sildenafil and vardenafil, while tadalafil has a different structure and pharmacokinetic properties.

3. Start of action. Sildenafil begins to act after 40 minutes, Tadalafil - after 40-50 minutes, and buy vardenafil which is available in our pharmacy - in 20 minutes, in a maximum of half an hour.

4. Highest concentration. Peak concentrations for vardenafil and sildenafil are observed 1 hour after administration, and for tadalafil - after 2 hours.

5. Eating together. Vardenafil, price which is acceptable for most clients of our pharmacy, it is not recommended to take it with fatty foods. Same as sildenafil. Tadalafil can be taken regardless of the fat content of the food you eat.

Generic Levitra (Vardenafil 20 mg)

6. Half-life from the blood. Tadalafil buy which you can buy in our pharmacy, is cleared from the blood plasma after 20 hours, and vardenafil and sildenafil - after 4 hours.

7. Interaction with alcohol. Vardenafil is compatible with small doses of alcohol, while tadalafil and sildenafil should not be mixed with alcoholic beverages.

Generic Cialis (Tadalafil 20 mg)

As it becomes clear from the list above, each medicine has its own characteristics and it cannot be said that they completely coincide in the effect that they have on the man’s body. You can find your medicine only by testing all the options.

Sildenafil 50 mg is a potency regulator. The drug is used regardless of gender to increase libido. In clinical practice, the drug is used not only to treat erectile dysfunction, but also pulmonary hypertension due to its vasodilating effect on the vascular endothelium in the pulmonary circulation. The medication is available in an easy-to-take tablet form and is intended for once daily use.

Other names and classification

ATX code: G04BE03.

International nonproprietary name

Sildenafil.

Trade names

• Vertex;
• Dynamic;
• Vizarsin;
• Revatio;
• Sildenafil-C3;
• Tornetis.

Registration number

Composition and dosage forms

The drug is available in tablet form. The core of each tablet consists of the active component - 50 mg of sildenafil citrate.

To facilitate absorption and increase bioavailability, auxiliary ingredients are added to the drug during the production process:

• microcrystalline cellulose;
• croscarmellose sodium;
• dehydrogenated calcium hydrogen phosphate;
• Magnesium stearate.

The mixture of components gives the round tablets a white color. Units of the drug are coated on top with a film coating that is soluble in the intestines. The film is based on talc, titanium dioxide, polyethylene glycol 4000, hypromellose. Tablets are contained in 15 pieces in blister packs. Blisters are placed in a cardboard pack of 6 pieces. In addition, the tablets are available in polyethylene jars of 90 pieces.

Pharmacological group

The drug belongs to potency regulators that suppress the action of phosphodiesterase-5 (PDE-5).

pharmachologic effect

The synthetic drug selectively blocks cyclic guanosine monophosphate (cGMP), located in PDE-5.

Phosphodiesterase is located in the corpus cavernosum of the genital organ in men and in the pulmonary vessels. As a result of achieving a therapeutic effect, erectile function is restored and the natural physiological response to psychological arousal of a sexual nature is improved.

The active component does not have a direct relaxing effect on the cavernous bodies in the genital organ.

Sildenafil enhances nitric oxide relaxation of the corpora cavernosa by soft fabrics. During sexual stimulation, with increased production of nitric oxide, inhibition of PDE-5 and an increase in the concentration of cGMP are observed. As a result of achieving a therapeutic effect, smooth muscles relax and blood supply to the corpus cavernosum increases.

Sildenafil is a reuptake inhibitor, which helps to enhance ejaculation of the erect penis. In addition, the chemical compound has a vasodilating effect on the pulmonary vessels. Thanks to this effect, hypertension in the pulmonary circulation is reduced.

After oral use, the tablets are broken down by the enzymatic action of esterases. small intestine, sildenafil is released and diffuses into the local bloodstream.

Bioavailability varies depending on individual characteristics from 25% to 63%. With a single dose, maximum values active substance in blood plasma are fixed within 0.5-2 hours. The drug substance undergoes transformation in hepatocytes with the formation of an N-desmethyl metabolite.

Together with the metabolic product, sildenafil binds to plasma proteins by 95-96%.

The half-life is 3-5 hours. The drug leaves the body with urine (13%) in the form of metabolites, 80% - together with feces.

Indications for use of Sildenafil 50 mg

The drug is used in clinical practice to treat impotence caused by dysfunction of the muscles of the penis, or to increase libido. The drug is suitable for both men and women and has the same effect regardless of the patient’s gender.

In rare cases, the drug is prescribed for the treatment of pulmonary hypertension as part of complex therapy.

For men

The drug is used to restore potency necessary for satisfactory sexual intercourse and is prescribed for the treatment of erectile dysfunction of various origins.

In the first case, to achieve a stable erection, you need to take the pills an hour before sexual intercourse. It is recommended to take 25-100 mg per day, depending on individual needs and the body’s reaction.

For women

The drug helps to enhance sexual activity and sexual desire in women during menopause or restore libido after surgical intervention for resection (removal) of the uterus. The drug has a positive effect on the female reproductive system, increases the sensitivity of the internal and external genital organs.

The medicine reduces the time to achieve natural arousal and increases the secretion of vaginal lubrication.

The drug can be used in the fight against frigidity.

Method of administration and dosage of Sildenafil 50 mg

For treatment high blood pressure in the pulmonary arteries the drug is taken 2 times a day with an interval between doses of 6-8 hours. A single dosage is 25 mg. The maximum permissible dosage per day is 60 mg. In case of poor tolerance, the drug is taken once in a daily dose of 25 mg per day.

To treat erectile dysfunction, you need to take 50 mg one hour before expected sexual intercourse.

A single dosage will be sufficient for sexual stimulation in both mild and advanced stages of erectile dysfunction. In some cases, if well tolerated, the dosage may be increased to 100 mg per day. The maximum dose is 0.1 g per day.

How long does it last?

The time to achieve and the duration of the therapeutic effect depend on the individual characteristics of the patient’s body. Mainly from the speed of general metabolism. The average duration of action of the drug is 4 hours, the maximum is 12 hours.

How long can it be used?

For effective treatment For penile dysfunction, andrologists recommend taking the medicine for 2 months. In this case, after a single use, it is necessary to take a break of 24-48 hours before the next dose.

special instructions

Before starting drug therapy, you must undergo medical examination to identify pathologies of the cardiovascular system. If you have congenital heart disease or unstable angina, taking the medicine is not recommended.

It is necessary to take precautions and undergo regular examination by the attending physician for patients with anatomical deformation of the genital organ:

• angulation;
• Peyronie's syndrome;
• cavernous fibrosis.

You should take the drug with caution during an erection, which is accompanied by pain due to the development of pathological processes. Priapism can develop due to malignant neoplasms and sickle cell anemia. People prone to bleeding or suffering from stomach ulcers and duodenum, consultation with a doctor is required before taking the drug.

In old age

For liver dysfunction

For impaired renal function

Side effects of Sildenafil 50 mg

If there is hypersensitivity to the chemical compounds included in the drug, the development of angioedema, skin itching, anaphylactic shock, skin rashes, the appearance of erythema.

Disturbances in the gastrointestinal tract are accompanied by asthenia, abdominal pain, nausea and vomiting.

With depression of the central nervous system the patient may feel a headache, flushing of the face, and loss of orientation in space. In rare cases, insomnia develops.

Disorders of the musculoskeletal system that arise from taking Sildenafil are characterized by pain in the joints and muscles, and an increase in muscle tone of the skeletal muscles.

Breathing disorders are accompanied by nasal congestion, inflammatory processes in the paranasal and paranasal sinuses, infectious diseases.

In some cases, visual impairment is accompanied by decreased visual acuity and inflammation of the conjunctiva of the eyes. Men are at risk of developing changes in color perception and blurring of objects.

A flu-like syndrome and infectious and inflammatory diseases may occur.

The vasodilating effect of the drug may occur.

There is a risk of developing infections genitourinary system and disorders of prostate activity. In exceptional cases, priapism may develop.

Impact on the ability to drive vehicles and other mechanisms

The drug does not cause addiction and does not affect the peripheral and central nervous system. Therefore, during the period of treatment with Sildenafil, it is allowed to control complex mechanisms, drive or other activities in which it is necessary to have developed fine motor skills, reaction speed and be concentrated.

Contraindications

The drug is strictly forbidden to be taken while undergoing treatment with nitric oxide or nitrate donors. Due to the possible development of anaphylactic shock, it is contraindicated to take the drug if you are hypersensitive to the active and auxiliary substances of the drug.

Overdose

• increased body temperature;
• sharp drop blood pressure;
• nasal congestion;
• headache and dizziness;
• flushed face;
• blurred vision;
• indigestion.

The severity of symptoms depends on the excess of the maximum permissible dosage. If signs of overdose appear, you must stop taking the drug and drink 10 tablets of activated carbon. If symptoms persist, you should seek medical attention medical care.

Interoperability and Compatibility

With simultaneous administration of CYP3A4 isoenzyme blockers, the clearance of sildenafil citrate decreases. With this combination, the serum level of sildenafil in the blood increases.

A similar increase in the concentration of the active substance is observed with simultaneous use of:

• Ritonavir;
• Indinavir;
• Saquinavir;
• Ketoconazole;
• Itraconazole.

Sildenafil can enhance the antihypertensive effect of nitrates.

In post-marketing practice, symptoms of diabetic rhabdomyolysis (acute necrosis of muscle tissue) have been reported after a single use of Sildenafil during drug therapy with Simvastatin.

With alcohol

Sildenafil is a synthetic drug that cannot be combined with alcohol and ethanol-containing drugs. Concurrent use of alcoholic beverages during drug therapy can cause severe dizziness with loss of orientation in space, severe arterial hypotension, respiratory depression and heart rate depression. The body may begin to collapse.

Conditions and shelf life

Manufacturer

CJSC "Northern Star", Russia.

Conditions for dispensing from pharmacies

The medicine is freely available.

Price in cities of Ukraine and Russia

The average cost of a potency regulator is about 163 UAH, while the price range in Russian pharmacies is from 73 to 576 rubles. Generics are more expensive than the original drug.

Analogues

If there is no positive reaction of the body to taking the drug, you can switch to another drug:

• Viagra;
• Dynamic;
• Maxigra;
• Sildenafil "North Star";
• Erexesil;
• Cialis.

A quick word about medications. Sildenafil

Viagra for prostatitis

Super P-Force Sildenafil and Dapoxetine Tablet- this drug has embodied the dreams of many millions of men. Most men (and their partners too!) want sexual intercourse to last much longer than the average 3-5 minutes, and for the erection to be powerful all this time. Try this product at least once, be sure you will like it!

SUPER P-FORCE is a medicine that helps men cope with problems arising in the intimate sphere. Its main advantage is that it contains Dapoxetine and Sildenafil, which actively influence the normalization of blood circulation in the genital organ.

Indications for use:

• disorders associated with premature ejaculation;
• weakness of potency.

Thanks to the main active ingredients, the product normalizes blood circulation and restores erectile function in a couple of hours. Besides intimacy last much longer due to delayed ejaculation. The half-life of the drug ranges from 5-6 hours, and effectiveness occurs 40-90 minutes after the first dose.

Compound: Each tablet contains 2 main substances: Sildenafil (100 mg) and Dapoxetine (60 mg).

Super P-Force instructions for use: The initial dosage ranges from 25-100 mg per day. The drug should be taken 1-3 hours before intimacy.

Cautions: Super P-Force is not recommended to be combined with antidepressants, cytocytic inhibitors, monoamine oxidase inhibitors, imidazoles and nitrates.

Side effect: during treatment with this drug, obvious side effects, which entail serious health problems, have not been found. However, in rare cases, minor changes in condition may be observed: headache, dizziness, diarrhea, nausea. Increased side effects are possible only by increasing the recommended dose, so you should first consult with a specialist.

Contraindications:

• sensitivity to the active components of the drug;
• arrhythmia;
• cardiovascular diseases;
• aortic stenosis;
• heart failure;
• lactose intolerance;
• hypotension;
• hypertension;
• mental and nervous disorders;
• cirrhosis of the liver;
• convulsive syndrome and epilepsy;
• dizziness of unknown origin;
• hypertrophic obstructive cardiomyopathy;
• previous myocardial infarction and stroke;
• The drug is not recommended for women and children, as well as men under 18 years of age.

Less strict contraindications include:

• exacerbation of a gastric or duodenal ulcer;
• thrombocytopenia;
• tendency to bleeding;
• multiple myeloma;
• sickle cell anemia;
• leukemia;
• deformation of the penis.

Package: There are 4 tablets in a blister, each containing 100 mg Sildenafil Citrate Sildenafil Citrate and 60 mg Dapoxetine Dapoxetine. Blister weight is about 4 g. Weight with packaging is 7 g.

Keep in a dry, cool, dark place away from children.

Best before date: 3 years.

Production: RSM Ltd., India.

Leave o Super P-Force

G.04.B.E Drugs for the treatment of erectile dysfunction

G.04.B.E.03 Sildenafil

Sildenafil is a powerful selective inhibitor of cyclic guanosine monophosphate (cGMP) - a specific phosphodiesterase type 5 (PDE5). Since PDE5, responsible for the breakdown of cGMP, is found not only in the corpus cavernosum of the penis, but also in the vessels of the lungs, being an inhibitor of this enzyme, it increases the content of cGMP in the smooth muscle cells of the pulmonary vessels and causes their relaxation. In patients with pulmonary hypertension (PH), taking sildenafil leads to vasodilation of the lungs and, to a lesser extent, other vessels.

Sildenafil is selective for PDE5 in vitro. Its activity against PDE5 is 10 times greater than that against other known phosphodiesterase isoenzymes: PDE6, which is involved in transmitting the light signal in the retina of the eye; PDE1 - 80 times; PDE2, PDE4, PDE7-PDE11 - more than 700 times. The activity of sildenafil against PDE5 is more than 4000 times greater than its activity against PDEZ, a cAMP-specific phosphodiesterase involved in myocardial contraction.

Sildenafil causes a slight and transient decrease in blood pressure (BP), which in most cases is not accompanied by clinical symptoms. After taking sildenafil orally at a dose of 100 mg, the maximum decrease in systolic anddiastolic blood pressure in the supine position averaged 8.3 mm Hg. Art. and 5.3 mm Hg. Art. respectively. After taking sildenafil at a dose of 80 mg 3 times a day, healthy male volunteers showed a maximum decrease in systolic and diastolic blood pressure in the supine position by an average of 9.0 mm Hg. Art. and 8.4 mm Hg. Art. respectively.

After taking sildenafil at a dose of 80 mg 3 times a day in patients with systemic arterial hypertension, systolic and diastolic blood pressure decreased by an average of 9.4 mm Hg. Art. and 9.1 mm Hg. Art. respectively.

In patients with PH who received a dose of 80 mg 3 times a day, the decrease in blood pressure was less pronounced: systolic and diastolic blood pressure decreased by 2 mm Hg. Art.

When administered once orally in doses up to 100 mg to healthy volunteers, it did not have a significant effect on electrocardiogram (ECG) parameters. When using sildenafil at a dose of 80 mg 3 times a day in patients with PH, clinically significant ECG changes were not detected.

When studying the hemodynamic effects of sildenafil with a single oral dose of 100 mg in 14 patients with severe coronary atherosclerosis (stenosis of at least one coronary artery more than 70%), mean systolic and diastolic blood pressure at rest decreased by 7% and 6%, respectively. compared to the baseline. Systolic pressure in the pulmonary artery decreased by an average of 9%. did not affect cardiac output and did not impair blood flow in stenotic coronary arteries.

In some patients, 1 hour after taking sildenafil at a dose of 100 mg, a mild and transient impairment of color perception (blue/green) was detected using the Fansworth-Munsel 100 test; 2 hours after taking sildenafil, these changes disappeared. It is believed that color vision impairment is caused by inhibition of PDE6, which is involved in light transmission in the retina of the eye. has no effect on visual acuity, contrast perception, electroretinography data, intraocular pressure or pupil diameter.

In patients with confirmed early age-related macular degeneration, a single dose of 100 mg did not cause significant changes in visual functions, in particular, visual acuity assessed using the Amsler grid, the ability to distinguish between traffic light colors assessed by Humphrey perimetry, and transient visual impairment. assessed using the photostress method.

Efficacy in adult patients with PH

The effectiveness of sildenafil was studied in 278 patients with primary PH (63%), PH associated with systemic connective tissue diseases (30%), and PH that developed after surgical treatment of congenital heart defects (7%). The majority of patients had II (107; 39%) or III (160; 58%) functional class of PH according to the World Health Organization (WHO) classification; less often, I (1; 0.4%) or IV (9; 3%) were defined functional classes. Patients with left ventricular ejection fraction less than 45% or a left ventricular shortening fraction of less than 0.2 were not included in the study, as well as patients for whom bosentan therapy was ineffective. doses of 20 mg, 40 mg or 80 mg were used together with standard therapy (patients in the control group received placebo). The primary endpoint was increase in tolerance to physical activity according to the 6-minute walk test 12 weeks after the start of treatment. In all three groups of patients receiving different doses, it significantly increased compared to placebo. Increases in distance walked (adjusted for placebo) were 45 m, 46 m and 50 m in patients receiving 20 mg, 40 mg and 80 mg doses, respectively. There were no significant differences between the groups of patients taking.Improvement in 6-minute walk test results was noted after 4 weeks of therapy. This effect persisted at 8 and 12 weeks of therapy. A mean treatment effect was consistently observed in the 6-minute walk test across all sildenafil groups compared with placebo in patient populations specifically selected for demographic, geographic, and disease characteristics. Baseline parameters (gait test and hemodynamics) and effects were generally similar in groups of patients with PH of different WHO functional classes and different etiologies.

A statistically significant increase in 6-minute walk test results was observed in the group of patients receiving 20 mg of sildenafil. For patients with functional classes II and III PH, placebo-adjusted improvements in 6-minute walk test scores were 49 m and 45 m, respectively.

In patients receiving all doses, mean pulmonary artery pressure was significantly reduced compared to placebo. In patients receiving doses of 20 mg, 40 mg and 80 mg, the decrease in pulmonary artery pressure adjusted for the placebo effect was: 2.7 mmHg. Art., 3.0 mm Hg. Art. and 5.1 mm Hg. Art. respectively. In addition, improvements were observed in the following parameters: pulmonary vascular resistance, right atrial pressure and cardiac output. Changes in heart rate and systemic blood pressure were insignificant. The degree of decrease in pulmonary vascular resistance exceeded the degree of decrease in peripheral vascular resistance. In patients treated with , a trend towards improvement in the clinical course of the disease was revealed, in particular a decrease in the frequency of hospitalizations for PH. The proportion of patients who improved by at least one WHO functional class over 12 weeks was higher in the sildenafil groups (28%, 36% and 42% of patients receiving 20 mg, 40 mg and 80 mg, respectively). ) than in the placebo group (7%). In addition, treatment with sildenafil compared with placebo resulted in improved quality of life, especially in terms of physical activity, and a trend towards improvement in the Borg dyspnea index. The percentage of patients who had to add another drug class to standard therapy was higher in the placebo group (20%) than in the groups of patients receiving doses of 20 mg (13%), 40 mg (16%), and 80 mg (10%). %).

Long-term survival information

In an extension study, it was found to improve survival in patients with PH.

Efficacy in adult patients with PH when combined with epoprostenol

The effectiveness of sildenafil was studied in 267 patients with stable PH on the background of intravenous epoprostenol. The study included patients with primary PH and PH associated with systemic connective tissue diseases.

Patients were randomized to placebo or sildenafil (fixed dose titration starting at 20 mg, up to 40 mg, and then 80 mg, three times daily) in combination therapy with intravenous epoprostenol. The primary endpoint was improvement in exercise capacity as measured by the 6-minute walk test 16 weeks after initiation of treatment. The increase in distance traveled in the sildenafil group was 30.1 m versus 4.1 m in the placebo group. In patients taking , the average pressure in the pulmonary artery significantly decreased by 3.9 mmHg. Art. compared to the placebo group.

Clinical outcomes

Sildenafil treatment significantly increased the time to clinical worsening of PH compared with placebo. Kaplan-Meier estimates that patients receiving placebo had a threefold higher risk of worsening (the proportion of patients worsening in the placebo group was 0.187 (0.12-0.26) and in the sildenafil group 0.062 (0.26). 02-0.10), confidence interval 95%). Time to clinical deterioration was defined as the time from patient randomization to the first sign of deterioration (death, lung transplantation, initiation of bosentan therapy, or epoprostenol dose change due to clinical deterioration). Twenty-three patients in the placebo group showed signs of clinical deterioration (17.6%), while in the sildenafil group, deterioration was observed in 8 patients (6%).

In patients with primary PH, the average deviation in the 6-minute walk test was noted: when used simultaneously with sildenafil - 26.39 m, when used with placebo - 11.84 m. In patients with PH associated with systemic connective tissue diseases - 18. 32 and 17.5 m respectively.

Efficacy and safety of sildenafil in adult patients with PH (when used simultaneously with bosentan)

Overall, the side effect profile in the two groups (simultaneous use of sildenafil and bosentan and bosentan monotherapy) was similar and consistent with the side effect profile of sildenafil.

Suction

Sildenafil is rapidly absorbed from the gastrointestinal tract after oral administration. Absolute bioavailability averages about 41% (from 25% up to 63%). Maximum concentration of sildenafil in blood plasma (C m ah ) is achieved within 30-120 minutes (on average 60 minutes) after ingestion on an empty stomach. After taking sildenafil 3 times a day in a dose range from 20 mg to 40 mg, the area under the concentration-time pharmacokinetic curve(AUC) and C m ax increase in proportion to the dose. When taking sildenafil at a dose of 80 mg 3 times a day, its concentration in the blood plasma increases nonlinearly. When taken simultaneously with food, the rate of absorption of sildenafil is reduced. When taken simultaneously with fatty foods, the time to reach maximum concentration (TC) m ah ) increases by 60 minutes, and C m ah decreases by an average of 29%, but the degree of absorption does not change significantly(AUC decreases by 11%).

Distribution

The volume of distribution of sildenafil at steady state averages 105 liters. After oral administration of sildenafil at a dose of 20 mg 3 times a day, the maximum concentration of sildenafil in blood plasma at steady state is about 113 ng/ml. The relationship between sildenafil and its main circulating N -demethyl metabolite with blood plasma proteins is about 96% and does not depend on the total concentration of sildenafil. 90 minutes after taking sildenafil, less than 0.0002 was found in the sperm of healthy volunteers% doses of sildenafil (average 188 ng).

Metabolism

Sildenafil is metabolized mainly in the liver under the influence of microsomal isoenzymes of cytochrome P450: isoenzyme CYP 3 A 4 (main pathway) and isoenzyme CYP 2 C 9 (optional path). The main circulating active metabolite is formed as a result of N -demethylation of sildenafil. The selectivity of this metabolite on PDE is comparable to that of sildenafil, and its activity on PDE5 in vitro is about 50% activity of sildenafil. The metabolite concentration in blood plasma is about 40% on the concentration of sildenafil. N- the demethyl metabolite undergoes further metabolism; its terminal half-life (T 1/ 2) is about 4 hours. In patients with pulmonary arterialhypertension (PAH) concentration ratio N -demethyl metabolite and sildenafil are higher. Concentration N -demethyl metabolite in blood plasma is about 72% of that of sildenafil (20 mg 3 times a day). The contribution of the metabolite to the pharmacological activity of sildenafil is 36%; its contribution to the clinical effect of the drug is unknown.

Removal

The total clearance of sildenafil is 41 l/hour, and the final half-life1/2- 3-5 hours. After oral administration, it is excreted in the form of metabolites mainly by the intestines (about 80% of the dose) and, to a lesser extent, by the kidneys (about 13% of the dose).

Pharmacokinetics in special groups of patients

Elderly patients

In elderly patients (65 years and older), the clearance of sildenafil is reduced, and the concentration of free sildenafil and its active N -demethyl metabolite in blood plasma is approximately 90% higher than in younger patients (18-45 years). Since the binding of sildenafil to plasma proteins depends on the age of the patient, the concentration of free sildenafil in the blood plasma in elderly patients is approximately 40% higher.

In mild to moderate renal failure (creatinine clearance (CC) 30-80 ml/min), the pharmacokinetics of sildenafil after a single oral dose of 50 mg does not change. In severe renal failure (creatinine clearance less than 30 ml/min), the clearance of sildenafil is reduced, which leads to an increase AUC at 100% and C m ax by 88% compared with values ​​with normal renal function in patients of the same age group. In patients with severe renal failure AUC and C max N - demethyl metabolite is 200 higher% and 79 % respectively, than in patients with normal renal function.

In volunteers with mild or moderate liver dysfunction (5-9 points on the Child-Pugh scale), the clearance of sildenafil is reduced, which leads to an increase in AUC (85%) and C m ax (47%) compared with values ​​with normal liver function in patients of the same age group. The pharmacokinetics of sildenafil in patients with severe liver dysfunction (more than 9 points on the Child-Pugh scale) has not been studied.

Population pharmacokinetics

When studying the pharmacokinetics of sildenafil in patients with PAH, age, gender, race, and indicators of renal and liver function were included in the population pharmacokinetic model. The data used for the population-based analysis included a wide range of demographic and laboratory parameters associated with liver and kidney function. Demographic variables, as well as parameters of liver or kidney function, did not have a statistically significant effect on the pharmacokinetics of sildenafil in patients with PAH.

In patients with PAH, after taking sildenafil in doses from 20 mg to 80 mg 3 times a day, its average steady-state concentrations were 20-50% higher than that of healthy volunteers. Minimum concentration of sildenafil in blood plasma (C max ) was 2 times higher than in healthy volunteers. The data obtained indicate a decrease in clearance and/or increase in bioavailability of sildenafil after oral administration in patients with PAH compared to healthy volunteers.

Pulmonary hypertension.

In animal experiments, it did not have any direct or indirect adverse effects on the course of pregnancy and the development of the embryo/fetus. Animal studies have shown toxic effects on postnatal development. Since adequate controlled studies of the use of sildenafil in pregnant women have not been conducted, the drug can be used during pregnancy only if the benefit to the mother outweighs the potential risk to the fetus.

It is unknown whether it is excreted into breast milk. If necessary, use the drug breast-feeding should be stopped.

Preclinical studies have not shown a negative effect of sildenafil on fertility.

Patients with impaired renal function

No dose adjustment is required, however, if the drug is poorly tolerated, the dose is reduced to 20 mg 2 times a day.

Patients with liver dysfunction

No dose adjustment is required in patients with mild or moderate liver dysfunction (5-9 points on the Child-Pugh scale), however, if the drug is poorly tolerated, the dose is reduced to 20 mg 2 times a day. The use of the drug has not been studied in patients with severe liver dysfunction (more than 9 points on the Child-Pugh scale) (see section "Contraindications").

Elderly patients (65 years and older)

No dose adjustment is required.

Children

The use of sildenafil in children under 18 years of age is contraindicated (insufficient data on efficacy and safety).

Patients receiving concomitant therapy

The simultaneous use of sildenafil and epoprostenol is discussed in the sections “Pharmacodynamics” and “Side Effects”.

Controlled studies assessing the effectiveness and safety of sildenafil in combination with other drugs (,) for the treatment of PH have not been conducted. Combination therapy with these drugs should be carried out with caution. It is possible that a dose adjustment of sildenafil may be required. However, there is no data on the need to increase the dose of sildenafil when used concomitantly with bosentan.

The effectiveness and safety of sildenafil in combination with other PDE5 inhibitors in patients with PAH have not been studied.

Concomitant use of sildenafil with strong isoenzyme inhibitors CYP 3 A 4 (eg, ketoconazole, itraconazole, ritonavir) is contraindicated.

If necessary, simultaneous use with moderate isoenzyme inhibitors CYP 3 A 4, such as and, the dose of the drug should be reduced to 20 mg 2 times a day in patients.

If necessary, simultaneous use with more powerful moderate isoenzyme inhibitors CYP 3 A 4, such as telithromycin and nefazodone, the dose of the drug should be reduced to 20 mg once a day.

Classification of the incidence of side effects according to recommendations

World Health Organization (WHO):

very often ≥ 1/10;

frequency ≥ 1/100 to< 1/10;

uncommon ≥ 1/1000 to< 1/100;

rare ≥ 1/10000 to< 1/1000;

very rarely< 1/10000, включая отдельные сообщения;

frequency unknown - based on available data, it is not possible to determine the frequency of occurrence.

Infections and infestations :

often - inflammation of the subcutaneous tissue, influenza, unspecified sinusitis.

Mental disorders:

often - insomnia, anxiety.

Nervous system disorders :

very often - headache;

often - tremor, paresthesia, unspecified burning sensation, hypoesthesia; frequency unknown - migraine.

Vascular disorders :

very often - hyperemia (redness of the facial skin);

frequency unknown - decreased blood pressure.

Respiratory, thoracic and mediastinal disorders :

often - unspecified bronchitis, nosebleeds, unspecified rhinitis, cough, nasal congestion.

Gastrointestinal disorders :

very often - diarrhea, dyspepsia;

often - unspecified gastritis, unspecified gastroenteritis, gastroesophageal reflux disease, hemorrhoids, bloating, dry oral mucosa.

Muscle, skeletal and connective tissue disorders :

very often - pain in the limbs; often - myalgia, back pain.

Skin and subcutaneous tissue disorders :

often - alopecia, erythema, increased sweating at night; frequency unknown - skin rash.

Metabolic and nutritional disorders : often - fluid retention (edema).

Visual disorders:

often - retinal hemorrhage, unspecified visual impairment, blurred vision, photophobia, chromatopsia, cyanopsia, eye inflammation, redness of the eyes;

rarely - decreased visual acuity, diplopia, impaired eye sensitivity.

Disorders of the hearing organ and labyrinth : often - vertigo;

frequency unknown - sudden deafness.

Disorders of the reproductive system and mammary glands :

often - gynecomastia, hemospermia;

frequency unknown - priapism, prolonged erection.

Blood and lymphatic system disorders:

often - unspecified anemia.

General disorders and reactions at the injection site:

often - fever.

The overall discontinuation rate of sildenafil at the recommended dose of 20 mg three times daily was low and no different from that in the placebo group (2.9%).

A placebo-controlled study examined the effect of adjuvant sildenafil therapy as an addition to intravenous epoprostenol. 134 patients with PAH received daily doses of 20 mg to 80 mg 3 times daily and epoprostenol, and 131 patients received placebo and epoprostenol. The duration of treatment was 16 weeks. The overall rate of discontinuation due to adverse events in the sildenafil/epoprostenol group was 5.2% compared with 10.7% in the placebo/epoprostenol group.

Interaction studies of sildenafil with other drugs were conducted in healthy volunteers, except where otherwise noted. These results are valid for other patient groups and administration methods.

Effect of other drugs on the pharmacokinetics of sildenafil Studies in vitro

The metabolism of sildenafil occurs mainly under the influence of cytochrome P450 isoenzymes: isoenzyme CYP3A 4 (main pathway) and isoenzyme CYP 2 C 9 (additional pathway), therefore inhibitors of these isoenzymes can reduce the clearance of sildenafil, and inducers can increase its clearance.

Researchin vivo

In a study on healthy male volunteers, the endothelin antagonist bosentan, which is a moderate isoenzyme inducer, CYP 3 A 4, CYP 2 C 9 and possibly CYP 2 C 19, in a steady state (125 mg 2 times a day) led to a decrease AUC and C m ax sildenafil at steady state (80 mg 3 times a day) by 62.6% and 55.4% respectively. Although co-administration of the two drugs was not accompanied by clinically significant changes in blood pressure in the supine and standing positions and was well tolerated by healthy volunteers, co-administration of bosentan should be done with caution.

Use of ritonavir (500 mg twice daily), an HIV protease inhibitor and a strong isoenzyme inhibitor CYP3A 4, in combination with sildenafil (100 mg once) led to an increase in C m ah sildenafil by 300% (4 times) and AUC by 1000% (11 times). After 24 hours, the concentration of sildenafil in the blood plasma was about 200 ng/ml versus 5 ng/ml when using sildenafil alone, which is consistent with the information about the pronounced effect of ritonavir on the pharmacokinetics of various cytochrome P450 substrates. Concomitant use of sildenafil with ritonavir is contraindicated.

The most powerful isoenzyme inhibitors CYP3A 4, such as and, may have effects similar to those of ritonavir. The simultaneous use of sildenafil with ketoconazole and itraconazole is contraindicated. Concomitant use of saquinavir (1200 mg 3 times daily), an HIV protease inhibitor and isoenzyme CYP3A 4, with sildenafil (100 mg once) leads to an increase in C m ah sildenafil at 140% and AUC by 210% respectively. had no effect on the pharmacokinetics of saquinavir (see section "Dosage and Administration").

With a single dose of sildenafil 100 mg during therapy with erythromycin, which is a moderate inhibitor of the isoenzyme CYP3A 4, in a steady state (500 mg 2 times a day for 5 days) an increase was detected AUC sildenafil at 182% (see section "Method of administration and dosage").

Such isoenzyme inhibitors CYP3A 4, Both telithromycin and nefazodone are thought to have effects similar to those of ritonavir. Such isoenzyme inhibitors CYP3A 4, how or can increase AUC 7 times. In this regard, with the simultaneous use of these inhibitors isoenzyme CYP3A 4 with sildenafil, you should be careful and adjust the dose of isoenzyme inhibitors CYP3A 4 (see section "Method of administration and dosage").

In healthy male volunteers (500 mg per day for 3 days) had no effect on AUC, C m ax, TC m ax , elimination rate constant or T1/2 sildenafil and its main circulating metabolite.

Cimetidine (800 mg), cytochrome P450 inhibitor and nonspecific isoenzyme inhibitor CYP3A 4, when taken together with sildenafil (50 mg), caused an increase in sildenafil concentrations in the blood plasma of healthy volunteers by 56%. A single dose of antacids (magnesium hydroxide and aluminum hydroxide) had no effect on the bioavailability of sildenafil.

The combined use of oral contraceptives (ethinyl estradiol 30 mcg and levonorgestrel 150 mcg) did not affect the pharmacokinetics of sildenafil.

Isoenzyme inhibitors CYP3 A4 and β-blockers

It has been established that in patients with PAH the clearance of sildenafil is reduced by approximately 30% when used simultaneously with weak or moderate isoenzyme inhibitors CYP3A 4 and by 34% when used simultaneously with β-blockers. AUC sildenafil when used at a dose of 80 mg 3 times a day was 5 times higher than when using sildenafil at a dose of 20 mg 3 times a day. In interaction studies with isoenzyme inhibitors CYP3A 4, such as and (excluding the most powerful isoenzyme inhibitors CYP 3 A 4 such as , ) AUC sildenafil increased in this concentration range.

Isoenzyme inducers CYP3 A4

The clearance of sildenafil increases approximately 3 times when used simultaneously with weak isoenzyme inducers CYP3A 4, which is consistent with the effect of bosentan on the clearance of sildenafil in healthy volunteers. It is expected that the simultaneous use of sildenafil with strong isoenzyme inducers CYP3A 4 will lead to a significant decrease in the concentration of sildenafil in the blood plasma. With the simultaneous use of sildenafil (at a dose of 20 mg 3 times a day) in adult patients with PAH and bosentan at a stable dose (62.5-125 mg 2 times a day), the same reduction in sildenafil exposure was observed as when used in healthy volunteers .

The effect of sildenafil on the pharmacokinetics of other drugs

Researchin vitro

Sildenafil is a weak isoenzyme inhibitor CYP 1 A 2, CYP 2 C 9, CYP 2 C 19, CYP 2 D 6, CYP 2 E 1 and CYP 3 A 4 cytochrome P450 systems ( IC 50 ≥ 150 µM). It is not expected to affect compounds that are substrates of these isoenzymes at clinically relevant concentrations.

Researchin vivo

Sildenafil has an effect on the system NO /cGMP and enhances the antihypertensive effect of nitrates. Its simultaneous use with nitric oxide donors or nitrates in any form is contraindicated.

With simultaneous use of the α-blocker doxazosin (4 mg and 8 mg) and sildenafil (25 mg, 50 mg and 100 mg) in patients with benign prostatic hyperplasia, an additional decrease in systolic/diastolic blood pressure in the supine position was 7/7, 9 /5 and 8/4 mm Hg. Art., and in the “standing” position- 6/6, 11/4 and 4/5 mmHg. Art. respectively. When using sildenafil in patients receiving sildenafil, rare cases of orthostatic hypotension, accompanied by dizziness, but not fainting, have been reported.

The use of sildenafil in patients taking α-blockers can lead to clinically significant arterial hypotension in patients with blood pressure lability.

When studying the interaction of sildenafil (100 mg) with amlodipine in patients with arterial hypertension, an additional decrease in systolic and diastolic blood pressure in the supine position by 8 mm Hg was noted. Art. and 7 mm Hg. Art. respectively. A similar reduction in blood pressure was observed with the use of sildenafil alone in healthy volunteers.

Signs of interaction of sildenafil (50 mg) with tolbutamide (250 mg) or warfarin (40 mg), which are metabolized by the isoenzyme CYP2C 9, not identified. (50 mg) did not cause any additional increase in bleeding time caused by acetylsalicylic acid as an antiplatelet agent (150 mg). (50 mg) did not enhance the antihypertensive effect of ethanol in healthy volunteers at C m ah ethanol in the blood 80 mg/dl.

In healthy volunteers at steady state (80 mg 3 times a day) caused an increase AUC and C m ax bosentan (125 mg 2 times a day) by 49.8% and 42%, respectively.

With simultaneous use of bosentan in adult patients with PAH at an initial dose of 62.5-125 mg 2 times a day and sildenafil at a dose of 20 mg 3 times a day, a smaller increase in AUC bosentan compared to healthy volunteers receiving a dose of 80 mg 3 times daily.

Sildenafil in a single dose of 100 mg had no effect on the steady-state pharmacokinetics of the HIV protease inhibitors saquinavir and ritonavir, which are substrates of the isoenzyme CYP 3 A 4.

Sildenafil did not have a clinically significant effect on the plasma concentrations of oral contraceptives (ethinyl estradiol 30 mcg and levonorgestrel 150 mcg).

To avoid complications, use strictly as prescribed by your doctor!

The effectiveness and safety of sildenafil in patients with severe PH (functional class IV) has not been proven. If the patient's condition worsens during drug therapy, the possibility of switching to therapy used to treat this stage of pulmonary hypertension (for example, epoprostenol) should be considered (see section "Dosage and Administration"). When used together with bosentan or other isoenzyme inducers CYP 3 A 4 Dose adjustment may be required.

The benefit/risk ratio of sildenafil in patients with functional class I PH has not been established. Studies on the use of sildenafil in the treatment of secondary PH, with the exception of PH associated with connective tissue diseases and residual PH, have not been conducted.

Arterial hypotension

Sildenafil has a systemic vasodilating effect, leading to a slight transient decrease in blood pressure. Before prescribing the drug, it is necessary to carefully assess the risk of possible undesirable manifestations of the vasodilating effect in patients with arterial hypotension (BP).< 90/50 мм рт. ст. в состоянии покоя), гиповолемией, тяжелой обструкцией выходного тракта левого желудочка (стеноз аорты, гипертрофическая обструктивная кардиомиопатия), а также с редко встречающимся синдромом множественной системной атрофии, проявляющимся тяжелым нарушением регуляции АД со стороны вегетативной нервной системы.

Since the combined use of sildenafil and α-blockers may lead to the development of symptomatic arterial hypotension in sensitive patients, the drug should be used with caution in patients taking α-blockers. To minimize the risk of postural hypotension in patients taking α-blockers, start taking Sildenafilshould be done only after stabilization of hemodynamic parameters in these patients has been achieved. The physician should inform patients about what actions to take if symptoms of postural hypotension occur.

Cardiovascular complications

During post-marketing use of sildenafil for the treatment of erectile dysfunction, adverse events such as serious cardiovascular complications (including myocardial infarction, unstable angina, sudden cardiac death, ventricular arrhythmia, hemorrhagic stroke, transient ischemic attack, hypertension and hypotension), which had a temporary association 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 occurred shortly after sexual activity, and some of them occurred after taking sildenafil without subsequent sexual activity. It is not possible to establish a direct connection between the observed adverse events and the specified factors or other reasons.

Visual impairment

Rare cases of the development of anterior non-arteritic ischemic optic neuropathy as a cause of deterioration or loss of vision have been reported with the use of all PDE5 inhibitors, including. Most of these patients had risk factors such as optic disc excavation, age over 50 years, diabetes, arterial hypertension, ischemic disease heart disease, hyperlipidemia and smoking. In case of sudden loss of vision, patients should immediately stop taking the drug and seek medical help.

Patients who have previously had cases of anterior non-arteritic ischemic optic neuropathy have an increased risk of developing this disease. In this regard, the doctor should discuss with the patient the possible risks of using PDE5 inhibitors. In such patients, the drug should be used with caution and after a careful assessment of the benefit-risk ratio.

A small number of patients with hereditary retinitis pigmentosa have genetically determined dysfunction of retinal phosphodiesterases. There is no information on the safety of sildenafil in patients with retinitis pigmentosa; therefore, the use of sildenafil in such patients is contraindicated.

Hearing impairment

Some post-marketing and clinical studies have reported cases of sudden deterioration or loss of hearing associated with the use of all PDE5 inhibitors, including. Most of these patients had risk factors for sudden deterioration or loss of hearing. A cause-and-effect relationship between the use of PDE5 inhibitors and sudden hearing loss or deterioration has not been established. In case of sudden deterioration in hearing or hearing loss while taking the drug, you should immediately consult your doctor.

Bleeding

Sildenafil enhances the antiplatelet effect of sodium nitroprusside, a nitric oxide donor, on human platelets in vitro. There are no data on the safety of sildenafil in patients with a tendency to bleeding or exacerbation of gastric and duodenal ulcers, so the drug should be used with caution in these patients. The incidence of epistaxis in patients with PAH associated with diffuse connective tissue diseases was higher (- 12.9%, placebo - 0%) than in patients with primary PAH (- 3%, placebo - 2.4%). In patients receiving in combination withvitamin K antagonist, the incidence of nosebleeds was higher (8.8%) than in patients not taking a vitamin K antagonist (1.7%).

Anatomical deformation of the penis and priapism

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 the development of priapism (sickle cell anemia, multiple myeloma, leukemia).

If an erection lasts more than 4 hours, you should immediately seek medical help. If immediate medical intervention is not carried out, damage to the tissues of the penis and complete loss of potency are possible.

Concomitant use with bosentan

When using sildenafil during initial therapy with bosentan, there was no improvement in patient condition (assessed using the 6-minute walk test) compared with bosentan monotherapy. The results of the 6-minute walk test differed between patients with primary PAH and PAH associated with systemic connective tissue diseases. In patients with PAH associated with systemic connective tissue diseases, the outcome of concomitant use of sildenafil and bosentan was worse than with bosentan monotherapy, but better than in patients with primary PAH treated with bosentan monotherapy. Thus, the physician should evaluate the outcome of therapy when using sildenafil and bosentan concomitantly in patients with primary PAH, based on their experience in treating PAH. The simultaneous use of the drug and bosentan in patients with PAH associated with systemic connective tissue diseases is not recommended.

Concomitant use with other PDE5 inhibitors

The effectiveness and safety of simultaneous use of sildenafil with other PDE5 inhibitors in patients with PAH have not been studied, so the use of this combination is not recommended.

Since dizziness, decreased blood pressure, chromatopsia, blurred vision and other side effects may occur when taking sildenafil, caution should be exercised when driving or engaging in other potentially dangerous activities. dangerous species activities that require increased concentration and speed of psychomotor reactions. You should also be careful about the individual effect of the drug in these situations, especially at the beginning of treatment and when changing the dosage regimen.

Film-coated tablets, 20 mg.

15 tablets in a blister pack made of polyvinyl chloride or polyvinyl chloride/polyvinylidene chloride film and aluminum foil.

90 tablets in a high-density polyethylene jar.

6 blister packs of 15 tablets each or one jar along with instructions for use in a cardboard pack.

Store in a place protected from light at a temperature not exceeding 25 °C.

Keep out of the reach of children.