Inactivity precio de sildenafil tablets. Sildenafil in modern urological practice. Indications for use

A.G. Martov

D.V. Ergakov

City Clinical Hospital No. 57 (Moscow), Department of Urology (minimally invasive methods of diagnosis and treatment of urological diseases)

“EFFECTIVE PHARMACOTHERAPY. Urology and Nephrology” No. 2 (15) | 2014

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The review examines the epidemiology, etiology and pathogenesis of erectile dysfunction. The clinical effects of the most long-used drug for the treatment of erectile dysfunction, sildenafil, which is also a reference drug in comparative clinical studies of the effectiveness of phosphodiesterase type 5 inhibitors, are characterized. It is noted that taking sildenafil leads to an improvement in the condition of patients of different ages, regardless of the etiology, severity and timing of erectile dysfunction. Data on the safety of the drug sildenafil are provided. The prospects for long-term continuous use of the drug are discussed.

Introduction

Erectile dysfunction (ED) is a pressing problem in urology. This is due not only to the high prevalence of ED in the population, but also to a revision of views on the causes of ED, changes in therapeutic approaches, the study of the relationship between ED and symptoms of the lower urinary tract, the need to correct erectile dysfunction after various urological operations (radical prostatectomy, urethroplasty, transurethral endoscopic surgery) .

ED is defined as the permanent or temporary inability to achieve and maintain an erection sufficient for successful sexual intercourse. Despite the fact that ED is not life-threatening, the appearance of sexual disorders leads to rapid personal and social maladaptation of the patient. In addition, in some cases, ED may be the first symptom of serious diseases (diabetes mellitus, demyelinating diseases of the spinal cord).

According to classical population studies conducted in the 20th century, the prevalence of ED increases with age. In men over 21 years of age, the incidence of ED is 10%, and among men over 60 years of age this figure triples. In the most socially active category of men (40–70 years old), 50% suffer from ED. Moreover, the frequency of ED is approximately the same among representatives of all races and continents.

Causes of erectile dysfunction

Traditionally, the causes of erectile dysfunction are divided into organic and psychogenic. However, psychogenic factors, as a rule, are secondary in nature, reflecting the response of the patient’s higher nervous activity to a primary violation of sexual function. Thus, in the vast majority of cases, ED is caused by organic disorders of the blood circulation and innervation of the penis, which is confirmed by numerous fundamental studies of the mechanisms of erection and clinical experience in treating patients with ED.

Among the organic causes of erectile dysfunction are hormonal disorders associated with a primary or secondary decrease in testosterone levels due, for example, to trauma, inflammation of the testicles, or increased levels of prolactin in the body, which suppresses testosterone production. ED can also be caused by systemic damage to the vascular bed as part of atherosclerosis, diabetic macroangiopathy and neuropathy, autointoxication as part of renal and liver failure, demyelinating diseases of the central nervous system (multiple sclerosis, Alzheimer's disease), and exposure to medications (antidepressants). In addition, ED can be caused by traumatic disruption of the innervation and blood circulation of the penis as a result of operations on the pelvic organs, radiation and various injuries. A separate group of causes includes ED, which occurs as a result of the loss of the veno-occlusive mechanism in the veins of the penis, which leads to rapid loss of erection.

Based on the above facts, the appearance of erectile dysfunction in socially active men should be a reason to consult a doctor. Unsubstantiated advertising of herbal medicines and dietary supplements in the media has led to patients self-medicating for a long time. They often turn to specialists already having severe vascular and neurogenic disorders, accompanied by severe fibrosis of the corpora cavernosa, which leads to an increase in the frequency of penile arthroplasty.

Mechanisms of occurrence and maintenance of erection

Let us briefly describe the basic mechanisms of the occurrence and maintenance of an erection. Somatic innervation of the penis is carried out from the sacral erection center, which is located at the level of S2–S4. In the latter, impulses come from the cerebral cortex as a result of audiovisual and tactile stimulation. At the endings of the efferent fibers, nitric oxide is released, which is the main mediator of relaxation of the vascular bed of the corpora cavernosa of the penis. The production of nitric oxide in the endothelium of the vessels of the cavernous bodies leads to the expansion of the latter and the occurrence of an erection. Nitric oxide is synthesized from the amino acid L-arginine after exposure to the enzyme NO synthetase. By penetrating the cell membrane and activating the system for the production of cyclic guanosine monophosphate (cGMP), nitric oxide leads to relaxation of the smooth muscle cells of the vessels of the cavernous bodies of the penis both during systole and diastole. To maintain an erection during the time required for sexual intercourse, the inclusion of mechanisms that prevent the outflow of venous blood from the penis is required. This effect is achieved by compression of the venous plexus between the tunica albuginea and the cavernous sinuses. Additional compression is carried out using voluntary contraction of the ischiocavernosus muscles. The enzyme cGMP phosphodiesterase type 5 blocks the intracellular cGMP production system, thus causing detumescence. The sympathetic innervation of the penis is also responsible for the cessation of erection; the sympathetic center is located at the Th4–L2 level, and the effect occurs through the release of norepinephrine and interaction with alpha-adrenergic receptors of cavernous smooth muscle cells. Subsequently, smooth muscle cells contract, which leads to loss of erection.

Drug treatment of erectile dysfunction

Phosphodiesterase type 5 inhibitors affect the relaxation of smooth muscle cells through competitive interaction with phosphodiesterase type 5 and promote the accumulation of cGMP inside cavernous smooth muscle cells, as well as in the cells of the smooth muscle layer of the penile arteries. Today, there are five drugs in the class of phosphodiesterase type 5 inhibitors on the market: sildenafil, vardenafil, tadalafil, udenafil and afanafil. All of them are characterized by a similar mechanism of action and approximately the same safety profile. Currently, according to the recommendations of the European and American Urological Associations, a particular drug is prescribed depending on the patient’s preferences or personal experience, as well as in accordance with the recommendations of the urologist. Accordingly, in order to instruct the patient and determine the optimal dosage regimen for the drug if the patient has concomitant diseases, the physician must know the pharmacokinetic and pharmacodynamic characteristics of the drugs.

Clinical efficacy of sildenafil

Sildenafil is the most studied drug from the entire group of phosphodiesterase type 5 inhibitors. In addition, it is a reference drug for comparative clinical studies of the effectiveness of other phosphodiesterase type 5 inhibitors.

Sildenafil began to be used in the late 1990s, so the experience of its use exceeds 15 years. The history of the discovery of sildenafil is widely known: during clinical trials of the new antianginal drug, scientists noted a side effect, which was the improvement of erectile function. Moreover, unlike other drugs for the treatment of ED on the market at that time, no cases of priapism were observed while taking it.

The emergence of sildenafil prompted a number of clinical studies in this area. The term “impotence” has been replaced by the concept of “erectile dysfunction”, which implies the potential possibility of correcting existing disorders in the sexual sphere. Clinical studies of sildenafil have led to the development of new diaries and questionnaires to assess the state of male sexual function. Analysis of demographic indicators of participants in large-scale clinical trials made it possible to identify risk factors for ED, which in turn contributed to understanding the mechanisms of its development. Evidence has begun to accumulate that most cases of ED have an underlying somatic nature, and psychological problems are often secondary to primary vascular or nerve damage. Patients with erectile dysfunction who had not previously consulted a doctor received hope for improved sexual function, and to date, millions of men around the world have returned to their sexual lives thanks to taking this drug.

The clinical effectiveness of sildenafil citrate has been studied in numerous studies. One of the largest meta-analyses combined data from 11 double-blind, placebo-controlled studies that included more than 2,500 patients with erectile dysfunction. In the main group, an improvement in erection was noted in 76% of patients versus 22% in the placebo group, which led to a significant difference in the frequency of successful attempts at sexual intercourse - 66 and 26%, respectively. The effectiveness of various dosages of the drug was 65% for 25 mg, 74% for 50 mg and 82% for 100 mg. The high effectiveness of sildenafil was noted in different age groups. In the category of patients under 65 years of age, the effectiveness of the drug was 77.6% versus 69.2% in the older age group. According to research, the drug is effective compared to placebo in patients with erectile dysfunction, regardless of the cause of its development and severity.

Despite the high effectiveness of therapy with phosphodiesterase type 5 inhibitors, there remains a certain cohort of patients in whom taking this drug does not lead to an improvement in erection. Possible causes include improper medication use. Patients, especially at the beginning of treatment, should be advised to take sildenafil on an empty stomach at least 30 minutes before the planned start of sexual intercourse. Patients should be informed that the effect of the drug develops only against the background of adequate sexual arousal and largely depends on it. In many cases, treatment should begin with a maximum therapeutic dosage of 100 mg, which will allow for maximum results at the beginning of treatment and instill confidence in the success of therapy. In addition, studies have shown that in some patients the maximum effect of sildenafil is achieved by the sixth to eighth dose, and therefore in many patients the final assessment of the effectiveness of the drug should be made after several attempts to use it.

Sildenafil in the treatment of erectile dysfunction after prostatectomy

Effective selection of therapy for ED after prostatectomy is currently one of the urgent problems of urology, which is due to the increase in the number of operations, the development of nerve-saving surgical techniques, and the introduction of robotics. Numerous studies have examined risk factors for the onset of ED after surgery: type of surgery (non-nerve-sparing, mono- or bilateral nerve-sparing techniques), patient age, preservation of erection before surgery, socio-economic conditions (level of education, patient income), tumor stage, prostate size , urologist experience.

R. Raina et al. showed that sildenafil therapy is effective in 71.7% of patients after bilateral nerve-sparing surgery, in 50% after unilateral nerve-sparing prostatectomy and in 15% of patients after non-nerve-sparing surgery. It has been shown that one of the features of ED after radical prostatectomy is the possibility of progressive improvement in erection several years after the operation, so long-term follow-up is necessary to make a final judgment about the effectiveness of therapy.

E.K. Hong et al. observed 316 patients with ED after radical prostatectomy, which in 95% of cases was bilateral nerve-sparing. The effectiveness of sildenafil was 26% during the first 6 months, 36% from 6 to 12 months, 50% from 12 to 18 months, and 60% from 18 to 24 months after surgery.

Currently, most authors believe that to prevent the development of ED after radical prostatectomy, long-term use of phosphodiesterase type 5 inhibitors, and in particular sildenafil, in low therapeutic doses is necessary. This therapy is justified by data on the improvement of blood flow in the corpora cavernosa against the background of long-term continuous use of drugs, which serves as prevention of the development of a local scar-sclerotic process. H. Padma-Nathan et al. studied the effectiveness of sildenafil in the prevention of ED after radical prostatectomy. As a result of the study, patients who underwent bilateral nerve-sparing surgery and did not suffer from ED before surgery, starting from the second month of the postoperative period, received sildenafil in doses of 100 and 50 mg or placebo at bedtime for 36 weeks. Eight weeks after stopping treatment, 27% of men receiving sildenafil reported being able to have a normal sex life, compared with only 4% of those receiving placebo.

Sildenafil therapy can be an effective method of preventing ED in patients after radical prostatectomy as a result of improving the blood supply to the cavernous tissue, preventing the development of fibrotic changes in it. Long-term use of the drug in small doses for the rehabilitation of patients after transurethral and oncoproctological operations is based on the same principles.

Safety of sildenafil

The safety profile is an important characteristic of any pharmacological drug. The most common adverse events when taking sildenafil include headache (7%), facial flushing (7%), dizziness (2%), dyspeptic disorders (1.8%), nasal congestion (1.4%) and color vision impairment. (1.2%). In most studies, the incidence of adverse events and resulting treatment refusals was comparable in the groups of patients receiving sildenafil and placebo. The incidence of adverse events decreases as the duration of drug use increases. In another study, the incidence of all side effects, except visual disturbances and dyspepsia, decreased over the duration of drug use. At the beginning of the study, headaches were reported by 7% of patients, and after 16 weeks - less than 1%, the frequency of dizziness also decreased from 7% to less than 1%, and nasal congestion - from 1.4% to less than 0.5%, with that two thirds of patients increased their dose of sildenafil during this study. With long-term use, the frequency of adverse events of sildenafil does not exceed that of placebo.

Sildenafil in the treatment of erectile dysfunction in patients with comorbid diseases

A significant number of studies have examined the safety of the drug in patients with various intercurrent diseases, which distinguishes the safety profile of sildenafil from other drugs in this group.

Arterial hypertension is a risk factor for the development of ED. Despite the presence of some hypotensive effects in sildenafil, this drug is safe in patients with arterial hypertension, regardless of the use of antihypertensive drugs. According to research, the effectiveness of sildenafil in patients with arterial hypertension and ED is high and is 70% versus 18% compared with placebo. In the group of men taking two or more antihypertensive drugs, these figures were 71% versus 17.6%.

Various studies have noted the effectiveness of sildenafil in the treatment of ED in Parkinson's disease, multiple sclerosis, spinal cord injury, and in patients suffering from depression. The possibility of using sildenafil has been studied in patients who smoke for a long time, which is also a well-known risk factor for the development of ED. Thus, the effectiveness of sildenafil in the smoking group did not differ significantly from that in non-smoking patients with ED.

Typically, treating ED in patients with diabetes is difficult, and the effectiveness of the drug depends on the complications of diabetes and the severity of its course. In the absence of complications of diabetes mellitus, the results of using sildenafil do not differ from those in the population as a whole; in the presence of complications, the effectiveness of therapy exceeds placebo by 4 times (40% versus 10%).

Due to the fact that the main effect of the drug is a decrease in vascular tone, the effect of sildenafil on the cardiovascular system has been quite well studied. R.M. Zusman et al. assessed the effect of the drug on blood pressure in patients with ED who were and were not taking antihypertensive drugs. Although the authors noted a slight decrease in blood pressure levels in all groups of patients, statistically significant differences occurred in only a small number of cases. The men in the study were taking different types of antihypertensive medications. The most pronounced decrease in blood pressure occurred in patients not taking antihypertensive drugs, as well as in those receiving calcium antagonists. At the same time, in none of the groups did the decrease in blood pressure have clinical significance. H.C. Hermann et al. studied the effect of sildenafil on exercise tolerance in patients with coronary heart disease. The authors found that sildenafil has a positive effect on myocardial blood supply.

Chronic use of sildenafil appears to reduce mortality from myocardial infarction. H. Padma-Nathan et al. showed that the incidence of death from myocardial infarction is 0.26% of patients with ED taking sildenafil per year, while the same figure in the general population is 0.6%.

When taking sildenafil, there is also an improvement in hemodynamics in the pulmonary circulation. A number of studies have studied the reduction of wedge pressure in the pulmonary trunk and the improvement of pulmonary vascular tone in response to hypoxia when using the drug as monotherapy or in combination with other antihypertensive drugs. The administration of sildenafil led to an increase in exercise tolerance and an improvement in the quality of life of patients.

Possibility of long-term use of sildenafil

One of the most pressing topics in modern urology is the study of the long-term possibility of therapy with phosphodiesterase type 5 inhibitors. The long-term effectiveness of sildenafil was studied by F. Montorsi et al., who surveyed 2618 patients taking the drug for 3 years. Overall, 96% of respondents were satisfied with the treatment and only 1.6% stopped taking it due to low effectiveness.

The possibility of long-term use of the drug allows one to count not only on the preservation of erectile function, but also on the partial normalization of lower urinary tract symptoms. The effect of sildenafil on lower urinary tract symptoms was studied by K. Sairam. One and three months after the start of treatment, there was a significant decrease in scores on the International Prostate Symptom Score (IPSS) and an increase in Quality of Life (QoL) scores, according to the degree of improvement in erectile function. The most likely reasons for these changes are improved blood circulation in the pelvis and normalization of the exocrine function of the prostate gland due to regular emptying of the gland ducts.

The constant use of small doses of sildenafil seems very promising in the treatment of diseases accompanied by dysfunction of the vascular endothelium. In addition to the main therapeutic effect of increasing blood flow to the corpora cavernosa, sildenafil can improve microcirculation in various organs. Endothelial dysfunction is considered as one of the links in the pathogenesis of the early stages of atherosclerotic vascular lesions.

The effect of sildenafil on the endothelial function of the coronary and brachial arteries has been studied in several studies. The use of sildenafil in doses of 25 to 100 mg was accompanied by an improvement in endothelial function in patients with heart failure, diabetes mellitus, coronary heart disease and smokers. The drug's ability to eliminate short-term deterioration of endothelial function caused by smoking has also been shown. In this regard, long-term use of phosphodiesterase inhibitors is not only harmless, but also very useful in terms of preventing the development of atherosclerosis. In patients with heart failure, long-term use of sildenafil, in addition to correcting endothelial dysfunction of the brachial and coronary arteries, also led to an improvement in pulmonary hemodynamics and had a moderate antiplatelet effect. The combined use of sildenafil and the angiotensin-converting enzyme inhibitor ramipril in this group of patients was accompanied by potentiation of the beneficial effect of both drugs on endothelial function.

The possibility of addiction to the drug has also been well studied. R. El-Galley et al. interviewed 82 patients by telephone two years after they were prescribed sildenafil. Among respondents, 41 (59%) continued to take the drug. 37% of respondents increased the initial dose of the drug due to a decrease in effectiveness. 17% of patients stopped taking it due to decreased effectiveness. Laboratory studies do not confirm the presence of an addictive effect when taking sildenafil. Thus, existing data do not support the presence of an addictive effect with long-term use of the drug.

Conclusion

Sildenafil was the first effective oral drug for the treatment of ED. With its advent, a new era began in the development of andrology, which in recent years has become an independent branch of modern urology. The clinical effectiveness of sildenafil has been assessed in a large number of studies conducted in many countries around the world. Taking the drug leads to an improvement in erectile function in patients of different ages, regardless of the etiology, severity and timing of ED. The effectiveness of the drug is long-term, with the vast majority of patients continuing to take sildenafil years after the start of treatment. Undesirable effects of sildenafil are generally mild in severity and their frequency decreases over time. Sildenafil does not have an adverse effect on the cardiovascular system. The drug helps improve the functional state of the vascular endothelium, which helps reduce the risk of developing cardiovascular diseases. Long-term use of the drug in small doses has a positive effect on the severity of lower urinary tract symptoms. The possibility of correcting endothelial dysfunction with the use of sildenafil as monotherapy or as part of a combination treatment may lead to an expansion of the indications for the use of this drug. The emergence of a new high-quality generic sildenafil will significantly expand the treatment options for patients with ED.

• KEY WORDS: erectile dysfunction, phosphodiesterase type 5 inhibitors, sildenafil, erectile dysfunction, phosphodiesterase type 5 inhibitors, sildenafil

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Composition and action

The drug contains only natural ingredients. The active substance of this product is considered to be ginseng, which stimulates sexual activity and increases the quantity and quality of sperm. In addition, ginseng is an ideal remedy for boosting immunity. As auxiliary components, Arabian sildenafil contains: seahorse, extract from the penis of a wild deer, goji berries and other components of plant and animal origin, which have a positive effect on the genitourinary system and the body as a whole.

Indications for use

Arabic sildenafil is recommended for men to treat and prevent erectile dysfunction of various origins. The use of this product allows not only to enhance and restore sexual activity, but also to enrich the body with valuable nutrients.

How to use

You need to take Arabic sildenafil 30 minutes before the intended sexual intercourse. This product can be used daily, but the daily dose should not exceed 1 tablet. The effect of the drug lasts for 36 hours.

Almost two decades have passed since the revolutionary Viagra appeared on the pharmaceutical market in 1998, opening unprecedented horizons in the treatment of erectile dysfunction. During this time, pharmacists not only proved the safety of sildenafil, the active ingredient in Viagra, but also created a whole group of follower drugs.

And, although the principle of action of all PDE-5 inhibitors is the same, each drug has its own characteristics.

Sildenafil: originality and uniqueness

It has been and remains the leader in sales among drugs for the treatment of erectile dysfunction for many years. It is known that Viagra is preferred by 50% of men experiencing erectile dysfunction. Over the years of its triumphant ascent to Olympus and basking in the rays of glory, sildenafil has been thoroughly studied, and every patient can familiarize itself with the test results.

Efficiency

Clinical studies have confirmed the high effectiveness of sildenafil. After 24 weeks of treatment, 56%, 77%, and 84% of men who took 25 mg, 50 mg, and 100 mg sildenafil, respectively, reported improved erections. Among patients taking dummy drugs (placebo), only 25% of the experiment participants noted any changes in a positive direction.

In addition, the effectiveness of sildenafil was confirmed in patients with diabetes mellitus (in 66.6% of cases).

The side effects of sildenafil are usually mild, and with constant use of the drug their intensity decreases. Discontinuation of sildenafil treatment due to poor tolerability is an extremely rare event. According to studies, its risk is comparable to the risk of placebo withdrawal due to side effects.

Tadalafil: duration of action

In 2003, another representative of the group of PDE-5 inhibitors entered the market - tadalafil (trade name Cialis). Following the famous Viagra, Cialis immediately wins many hearts. Unlike sildenafil, tadalafil acts for at least 36 hours, and the time of onset of the effect does not depend on food intake.

Efficiency

The trial, which lasted 12 weeks, showed that treatment with tadalafil was effective in 67 and 81% of men taking the drug at 10 mg and 20 mg doses, respectively.

In the placebo group, 35% of men reported a positive result. In patients with diabetes mellitus, tadalafil is effective in 64% of cases (25% in the placebo control group).

Vardenafil: convenience and results

The next significant discovery was vardenafil. Three pharmaceutical corporations took part in its creation: Bayer, GlaxoSmithKline and Schering Plow. In 2005, the original vardenafil, Levitra, appeared on the market.

Efficiency

After 12 weeks, during which volunteers were treated with vardenafil, 66, 76 and 80% of men taking 5 mg, 10 mg and 20 mg of the drug, respectively, reported improved erections. A positive placebo effect was reported in 30% of volunteers.

Post-marketing trials, which began after the drug entered the market and continue to this day, confirm the high effectiveness of vardenafil. The drug also improves erection in patients with serious illnesses, including diabetes.

Alternative dosage form

A new dosage form of vardenafil released by Bayer is dispersible tablets (Levitra ODT). Its positive aspects include ease of use, higher bioavailability and early onset of effect. The effects of dispersible vardenafil have been studied in several clinical trials. The results showed that the effectiveness of conventional and dispersible vardenafil tablets was approximately the same.

New active ingredients: the future of ED treatment

Despite the high efficiency and safety of the three developed drugs, scientists do not give up attempts and hopes to find new, even more effective and gentle remedies for the treatment of erectile dysfunction.

Approved for sale by the American Drug Control Association (FDA) in 2012. The original drug Avanafil is marketed under the trade name Stendra. A distinctive aspect of this PDE-5 inhibitor is its early onset of effect - approximately 65% ​​of men notice the appearance of an erection within 15 minutes after taking avanafil.

Lodenafil

Just like avanafil, lodenafil belongs to the new, latest generation of PDE type 5 inhibitors. The drug has very high bioavailability due to the breakdown in the body into two active components.

Today lodenafil is undergoing stage III clinical trials and has not yet been approved for use.

Sildenafil, tadalafil, vardenafil: comparison of indicators

Data from comparative studies of the main PDE type 5 inhibitors indicate that all three drugs are equally effective. This is also confirmed by leading experts of the European Association of Urology in recommendations for the treatment of erectile dysfunction, issued in 2012. Both the European and American Urological Associations recommend choosing a drug based on the patient's personal preference and individual tolerance.

Guidelines for the treatment of erectile dysfunction recognize PDE5 inhibitors as the treatment of choice for men with erectile dysfunction. A joint decision on which drug out of four on the market to choose is made by the doctor and the patient., based on tolerability, effectiveness and ease of use.

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Sildenafil is a powerful selective inhibitor of cGMP-specific PDE-5.

The physiological mechanism of erection is the release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. This, in turn, leads to an increase in cGMP levels, resulting in relaxation of the smooth muscle tissue of the corpus cavernosum and increased blood flow in the corpus cavernosum.

Sildenafil does not have a direct relaxing effect on the isolated corpus cavernosum, but enhances the relaxing effect of nitric oxide, causing inhibition of PDE5, which is responsible for the breakdown of cGMP in the corpus cavernosum.

After oral administration, it is quickly absorbed. The maximum concentration in blood plasma is achieved within 30-120 minutes (average 60 minutes) when taken orally on an empty stomach. Bioavailability varies from 25 to 63%.

When taken in combination with fatty foods, the rate of absorption decreases: Cmax decreases by an average of 29%, and the time to reach maximum concentration (Tmax) increases by 60 minutes, but the degree of absorption does not significantly change (the area under the concentration-time pharmacokinetic curve (AUC) decreases by 11%).

A randomized, double-blind, placebo-controlled study examined the effect of varying the dose of sildenafil (up to 100 mg) in men (n=568) with erectile dysfunction and hypertension taking more than two antihypertensive medications.

Sildenafil improved erections in 71% of men compared to 18% in the placebo group. The incidence of adverse effects was comparable to that in other patient groups, as well as in individuals taking more than three antihypertensive drugs.

Indications for use

What does Sildenafil help with? The drug is prescribed in the following cases:

• psychogenic erectile dysfunction;
• mixed erectile dysfunction;
• organic erectile dysfunction.

The drug is effective only with sexual stimulation.

Instructions for use of Sildenafil and dosage

Sildenafil tablets are taken orally 1 hour before sexual intercourse. For adults, a single dose is 50 mg per day.

Taking into account the tolerability and effectiveness of the drug, the dose can be reduced to 25 mg or increased to 100 mg.

The maximum dosage is 100 mg.

For elderly people, there is no need to change the standard dosage. For patients with impaired liver function, it is recommended to reduce the dose of the drug to 25 mg.

Side effects

The use of Sildenafil may be accompanied by the following side effects:

• Cardiovascular system: weakening of the tone of blood vessels, rushes of blood to various areas of the body;
• Digestive system: diarrhea, nausea, digestive disorders;
• Sense organs: blurred vision, changes in color perception, conjunctivitis, increased sensitivity to light;
• Urinary system: infection of the urinary duct;
• Reproductive system: dysfunction of the prostate gland;
• Central and peripheral nervous system: dizziness, insomnia, headaches;
• Musculoskeletal system: increased muscle tone, joint pain, muscle pain;
• Skin lesions: appearance of skin rashes;
• Respiratory system: pharyngitis, runny nose, infection of the respiratory system, various breathing disorders, sinusitis, nasal congestion.

Contraindications

Sildenafil is contraindicated in the following cases:

• allergy to medicine;
• permanent or temporary intake of nitrates;
• diseases for which it is recommended to limit sexual activity;
• children under 18 years of age. Sildenafil is not used in childhood;
• women. Treatment with Sildenafil is not carried out in women, as well as during breastfeeding (lactation) and pregnancy;
• severe liver disease;
• stroke or heart attack diagnosed in the last six months;
• congenital retinal abnormalities;
• defects in the formation of the penis (congenital and acquired);
• loss of vision due to ischemia.

Carefully:

• Anatomical deformation of the penis (angulation, cavernous fibrosis or Peyronie's disease).
• Diseases predisposing to the development of priapism (sickle cell anemia, multiple myeloma, leukemia, thrombocythemia).
• Diseases accompanied by bleeding.
• Exacerbation of peptic ulcer of the stomach and duodenum.
• Hereditary retinitis pigmentosa

Overdose

With a single dose of Sildenafil-SZ in a dose of up to 800 mg, adverse events were comparable to those when taking the drug in lower doses, but were more common.

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

Analogues of Sildenafil, list of drugs

If necessary, you can replace Sildenafil with an analogue of the active substance - these are the following drugs:

1. Viagra;
2. Kamagra;
3. Pemegra;
4. Pfiagra;
5. Sildigra;
6. Suhagra;
7. Tornetis;
8. Edegra.

When choosing analogues, it is important to understand that the instructions for use of Sildenafil, price and reviews do not apply to drugs with similar effects. It is important to consult a doctor and not change the drug yourself.

The average cost of the drug in Moscow pharmacies depends on the number of tablets and dosage - 25 mg, 20 tablets - 407-421 rubles.

Store at a temperature not exceeding 25 °C. Keep away from children. Shelf life – 3 years. Dispensed by prescription.

For sexual dysfunction and weak erection, the drug Sildenafil is often used. Its action is based on stimulating blood circulation in the pelvic organs, thereby increasing potency and prolonging the time of sexual intercourse.

Sildenafil has many analogues, starting from the well-known Viagra. How often you can take the drug “Sildenafil”, reviews, instructions and price of this drug are discussed in detail in our article.

Composition and description of the drug

The main active ingredient of the drug is sildenafil citrate. Based on sildenafil, the dosage is 25, 50 and 100 mg. In addition, the composition contains excipients: microcrystalline cellulose, aluminum hydroxide, magnesium stearate, croscarmellose sodium and dyes.

Dosage form

Sildenafil is available in the form of biconvex film-coated tablets. The color of the shell varies from pale blue to blue, pearlescent and marbled effects are allowed. Tablets are small in size, round or diamond-shaped, packaged in 1, 2 or 4 pieces per pack.

The dosage ranges from 25 to 100 mg, but there are drugs with increased concentrations of up to 150 mg. They should be taken only as prescribed by a doctor. During clinical studies, the safe daily dosage of sildenafil was established within 100 mg.

pharmachologic effect

The product is used to improve erectile function. Taken orally, it is a cGMP-specific phosphodiesterase inhibitor in the corpora cavernosa. The mechanism of action is the activation of the enzyme due to the release of nitric oxide during sexual arousal. Sildenafil tablets have a powerful relaxing effect on isolated human corpora cavernosa. The effect of the drug is peripheral.

The pharmacodynamics of Sildenafril is selective, so natural sexual arousal is necessary for the effect. The active substance has a strong effect, helping to relax smooth muscles, increase blood supply and dilate blood vessels in the genital organ. Metabolized in the liver, excreted mainly in feces and urine.

History of creation

Initially, the effect and pharmacodynamics of sildenafril on stimulation of blood flow in the myocardium were studied. The drug was synthesized to create effective drugs against coronary heart disease, but its effect was not enough. In the process of research, “side effects” were identified to increase blood supply to the pelvic organ, due to which the developments changed orientation, and the possibility of using the drug to improve potency and treat erectile dysfunction began to be studied.

In the United States, sildenafil is marketed under the Viagra brand by Pfizer. Thus, this is the same drug, the composition and pharmacodynamics of which are identical. Developments were carried out relatively recently - in 1992, but the brand very quickly became recognizable and in demand all over the world.

Now Sildenafil has many analogues, many similar drugs use other mechanisms of action and active ingredients, but the name “Viagra” itself has become a household name.

Indications for use

The drug is used for physiological disorders of erectile function. Activation of the inhibitor occurs during sexual arousal, and the drug itself does not affect this function, but only increases the relaxation of the smooth muscles of the penis, due to which blood flow improves and a persistent erection is observed.

Most often the drug is used to treat:

• Erectile disorders of various etiologies;
• Sexual dysfunction at different ages;
• In complex therapy of impotence;
• In the treatment of pulmonary hypertension.

The treatment regimen and the use of additional medications must be agreed with the attending physician. Typically, the product is used as needed, and not on a regular basis. Due to its selective effect, the drug does not require adjustment in case of diagnosed renal or liver failure. However, the combination of certain medications may reduce or increase the effect of taking Sildenaphine, so you should get your doctor’s advice before taking it.

Drug interactions

The drug should not be taken with other products containing nitrates in any form. Simultaneous intake of enterosorbents reduces absorption, as does fatty foods.

Concentration in the blood increases when taken simultaneously with:

• Cimetidines;
• Erythromycin;
• Ketoconazole;
• Calcium antagonists;
• Beta-blockers;
• Hypoglycemic drugs.

Due to the vasodilating effect, a decrease in blood pressure is possible, so patients with hypotension need additional consultation with a doctor before taking it.

After the age of 65 years, the effect of the drug may not be as strong, and in case of existing problems with cardiac activity, it is also necessary to weigh the pros and cons before prescribing Sildenafil.

Time of action

The drug is taken orally, about an hour before sexual intercourse. The effect of the drug lasts about five hours, but only under the condition of sexual arousal. A single dosage is 50 mg. The maximum daily dose is 100 mg. If necessary, the drug is used in a dosage of 25 mg.

The big advantage of using the drug is the absence of an addictive effect.

Thus, the effect of the drug does not decrease over time and can be used over a long period.

Contraindications

The benefits of the drug will not always be justified. Due to the content of nitric oxide, simultaneous use with similar drugs is prohibited. For example, when using products containing nitric oxide or nitrates in any form.

In addition, the use of the product is prohibited in the following cases:

• Hypersensitivity to the components of the drug;
• Deformations of the penis with impaired blood supply.

When using, be sure to consult a doctor to eliminate the risk of side effects and contraindications. This is especially important in old age, when increased stress can cause problems with the cardiovascular system.

Side effects

In the absence of medical contraindications, the drug is usually well tolerated. However, side effects are possible, which manifest themselves in the form of headache, redness of the face and a feeling of hot flashes. Possible general malaise, sinus congestion. Sometimes - digestive disorders, photosensitivity. Due to the stimulation of blood circulation and the production of the hormone cGMP-specific phosphodiesterase, visual disturbances, a decrease in the sensitivity of the color of objects (blue and green shades), as well as an increased negative reaction to light are possible.

If such symptoms appear, you should stop taking the drug, and also contact your doctor to agree on replacing the drug with a similar one.

If the negative reactions are too strong, you can take an enterosorbent and an antihistamine, and also go to the hospital for gastric lavage and stabilizing agents.

Reviews

Reviews from men about taking Sildenafil are mostly positive. The drug helps to strengthen erection and prolong the time of sexual intercourse, as well as normalize sexual function.

The effect lasts up to five hours, and regular use maintains the positive effect, helping to lead a full sex life without additional stimulation.

Negative reviews about Sildenafil mostly blame the discomfort that may occur after using the product. The most common complaints are dizziness, tinnitus and flushing of the face. Side effects are aggravated by simultaneous intake of alcoholic beverages, with which the tablets are completely incompatible. How often you can take sildenafil depends on the individual characteristics of the body, but if side effects appear quite often, you should consult a doctor to select a more suitable analogue.

Popular analogues

The active substance sildenafil is included in many medicines with similar effects. The patented trademark is "Viagra", but there are also many similar drugs.

Analogs for the active substance:

• "Dynamiko";
• "Maxigra";
• "Erexesil";
• "Sildenafil - C3";
• "Potential";
• "Pfiagra";
• "Sildigra".

Compared to its analogue, Sildenefril has a very reasonable price. This is due to the fact that the medicine is produced in India, which means it belongs to the so-called generics. They are characterized by a greater number of side effects than original products. That is why the consequences of taking Sildenafil in some cases can be unpredictable. However, if there are no medical contraindications and the dosage is strictly observed, the risk of side effects is minimal. That is why many urologists prescribe this remedy for the treatment of impotence in men at a lower financial cost.

What is the difference between Sildenafil and Viagra

Viagra appeared on the pharmaceutical market relatively recently, but the popularity of this drug for increasing potency has long become a household word. The developers have provided men with a unique opportunity to strengthen and normalize sexual function at almost any age. For young men, it will help increase sexual desire and prolong sex, and for the older age group, it will help restore the possibility of full sexual intercourse.

The original drug is not cheap, so Viagra is not available to most consumers, especially for regular use.

A feature of patenting medicines is the short duration of protection for the original drug. Typically, a patent is valid for 5-10 years, after which any pharmaceutical company can produce its own product based on the substances and chemical compounds specified in the original. Of course, such drugs are produced under a different trade name and do not have the right to refer to the original brand to promote their products.

At the same time, this practice gives us more chances as buyers to purchase an inexpensive analogue. In many countries, the method of prescribing drugs by active substance and dosage is common, so it is possible to buy similar drugs at a more affordable price. In our country, this “function” is usually performed by a pharmacist in a pharmacy, who, at the request of the patient, can offer an analogue of the prescribed drug if it is not available or is overpriced. Of course, this approach is somewhat wrong, but the drugs described above contain an absolutely identical active ingredient, and in the same dosage. The difference is represented by additional substances, as well as the method of manufacturing and purification of the components.

Thus, the notorious “Viagra” has the same effect on the male body as “Sildenafil” and drugs containing it. According to reviews from patients and doctors who prescribe this remedy, different types of medications may cause different reactions in terms of symptoms, but a certain psychological effect is also observed. The use of Sildenafil is not as effective if the patient purchased it instead of the indicated Viagra, although the pharmacokinetics of both drugs are completely identical.

Comparison with popular analogues

In addition to Viagra, the drug has many other varieties, which also contain the active component sildenafil. In addition, there are indirect analogues of the drug, the effect of which is also to stimulate the blood supply to the genital organs, but with the help of other active substances. The most famous in this group are Vardenafil and Tadalafil. All three active components are used to increase erectile function in men, according to reviews, they have approximately the same effect, but they also have some differences.

Comparative characteristics:

1. Vardenafil or Sildenafil, which is better? Compared to Vardenafil, the second drug is more studied and tested. At the same time, both drugs cause a strong and long-lasting erection and allow you to prolong sexual intercourse with proper psychological stimulation. Their period of exposure is approximately the same, and taking Vardenafil occurs with a lower risk of side effects. The difference can be found in the full compatibility of Vardenafil with alcohol, as well as with a more aggressive effect, because an erection occurs within 15-20 minutes after taking the drug.
2. Tadalafil or Sildenafil, which is better? Both drugs have been sufficiently tested and have the same time of onset of effect and contraindications. The difference is the duration of action. for Sildenafil it is about five hours, while Tadalafil has the maximum possible effect among similar drugs - up to 36 hours. In addition, in small quantities, Tadalafil is compatible with alcoholic beverages, while Sildenafil and alcohol show complete incompatibility. The incidence of side effects with Sildenafil is slightly higher, so in this regard, preferences are not on its side.
3. Visarsin or Sildenafil, which is better? In terms of composition and pharmacokinetics, both drugs are almost identical. The main active ingredient is sildenafil, but Vizarsin contains dosages that are more convenient to take. The list of contraindications and side effects is the same, and the cost differs slightly, depending on the manufacturing company.

Modern drugs that stimulate sexual function in men are varied, but each of them is based on only three active ingredients. These are Sildenafil (brand name Viagra), Tadalafin (Cialis) and Vardenafil (Levitra). The latter substance was synthesized relatively recently, in 2005, and is distinguished by a strong effect and a minimal number of side effects.

Among the advantages of Tadalafin is its long-lasting effect, which lasts for 36 hours. If just such an action is needed, the best choice would be drugs from this group. On the side of sildenaphine there is a sufficiently studied effect and positive reviews of use all over the world. An ideal remedy, however, does not exist, so everyone should choose a drug according to individual preferences and quality of tolerability.

Storage conditions and shelf life of the drug

The drug is packaged in standard plastic blisters, the outer box is made of cardboard. There are different dosages and configurations. Usually these are 1, 2 or 4 tablets, but there are larger packages. Store away from direct sunlight in a cool place (temperature no higher than +25 degrees) and away from children. The shelf life is 2 years after production.

Sildenafil tablets, instructions and reviews of which are given in our information, are often used in the treatment of erectile dysfunction. They help normalize blood circulation in the penis, strengthen erections and prolong sexual intercourse. Apply as needed according to the calculated dosage.

The product has minimal possible side effects and can be used for a long period without reducing its effectiveness.

The main active ingredient is used in the manufacture of the well-known Viagra, and, according to reviews, it “works” no worse. Features of administration, pharmacological action and similar agents are discussed in our article.