Overview of Силденафил

What is Sildenafil?

Property	Description
Active Ingredient	Sildenafil citrate
Form	Oral Tablet (Film-Coated)
Pharmacological Class	Phosphodiesterase Type 5 (PDE5) Inhibitor
General Purpose	To promote targeted smooth muscle relaxation and increase localized blood flow.
Origin	Synthetic

What is Sildenafil and What Type of Drug is it?

Sildenafil (Силденафил) is a widely recognized synthetic prescription drug known by its primary ingredient, Sildenafil citrate. It is formally classified as a Phosphodiesterase type 5 (PDE5) Inhibitor. This classification establishes its focused mechanism, making it clinically recognized for treating conditions that benefit from increased blood flow. As an International Nonproprietary Name (INN), Силденафил represents the standardized generic medicine used across numerous global brands.

Composition, Form, and General Purpose

The active component, Sildenafil citrate, is formulated primarily as an oral tablet for systemic action, a convenient and distinctive feature. As a single-ingredient product, its therapeutic effect is derived entirely from the properties of the citrate compound combined with necessary pharmaceutical excipients. This composition supports the medicine’s general purpose: its selective enzyme inhibition enhances a natural signal in the body, promoting localized blood flow. This action is based on its role as a targeted vasodilator in select vascular beds, which is the functional principle that allows it to address conditions like pulmonary hypertension or assist with the physiological aspects of sexual function.

What side effects are possible with Силденафил?

Possible side effects and safety information

Sildenafil's official safety profile is based on data categorized by frequency and the physiological system affected, consistent with regulatory standards. The most Very Common side effects, reported in ten percent or more of patients, include headache and flushing. Common adverse reactions typically involve dyspepsia (indigestion), dizziness, nasal congestion, and various visual disturbances (e.g., color tinge, blurred vision).

Serious Adverse Reactions and Safety Restrictions

Official labeling documents rare, but clinically significant events reported in temporal association with Sildenafil use. These include serious cardiovascular events such as myocardial infarction and sudden cardiac death, and specific ophthalmic events like Non-arteritic Anterior Ischaemic Optic Neuropathy (NAION) (sudden loss of vision). The label also reports cases of priapism (prolonged erection) and sudden decrease or loss of hearing.

Usage is subject to explicit restrictions and contraindications defined in regulatory documents. Sildenafil is strictly contraindicated with the concomitant use of organic nitrates or the guanylate cyclase stimulator riociguat. It is also contraindicated in patients with severe hepatic impairment, resting hypotension (blood pressure less than 90/50 mmHg), or a history of NAION.

Population and Time-Related Notes

The prescribing information notes that symptomatic hypotension when co-administered with alpha-blockers is most likely to occur within four hours following Sildenafil administration. Regarding special populations, use is not recommended in pediatric patients for the Pulmonary Arterial Hypertension (PAH) indication due to safety concerns, and caution is advised for patients predisposed to priapism (e.g., sickle cell disease).

Overdose and Emergency Response

Overdose and When to Seek Help

Sildenafil overdose information is based strictly on documented findings from regulatory authorities, describing specific manifestations and required emergency actions. An overdose may result in exaggerated pharmacological effects, as symptoms are typically consistent with adverse events seen at recommended doses but occur with increased frequency and severity.

Documented Manifestations and Severe Outcomes

Manifestations of supratherapeutic exposure include acute signs of profound vasodilatation, such as hypotension (decreased blood pressure) and syncope (fainting). Severe outcomes reported include priapism (a prolonged erection lasting longer than four hours), which is considered an urgent medical situation to prevent tissue damage. Other serious events requiring immediate attention are sudden loss of vision or a sudden decrease or loss of hearing.

Official Emergency Response and Management

Regulatory guidance states that immediate medical attention must be sought in the event of accidental overdose or if any of the severe manifestations, such as a prolonged erection, occur. Treatment for Sildenafil overdose is symptomatic and supportive, and must be tailored to the patient's clinical status. No specific antidote is known to reverse the effects of Sildenafil. Due to the drug's high plasma protein binding, renal dialysis is not expected to accelerate its clearance. Patients with severe hepatic or renal impairment may experience reduced clearance, potentially leading to increased systemic exposure.

Therapeutic Uses of Силденафил

Main Uses and Benefits of Sildenafil

Sildenafil is a medication indicated for the management of two primary, distinct medical conditions. The therapeutic application is centered on conditions related to blood flow regulation. The medication is used for Pulmonary Arterial Hypertension (PAH), which is high blood pressure in the arteries that supply the lungs, and Erectile Dysfunction (ED), defined as difficulty getting or keeping an erection.

The drug is used to manage symptoms and achieve functional support for these conditions. For men with ED, it may support the natural response to sexual stimulation, and for PAH patients, it contributes to the management of their symptoms. The medication is an established therapeutic option for these conditions. The overall aim is to provide therapeutic value for both cardiovascular and sexual health needs.

Quick Fact: Supporting Management of Erection Difficulties

Regulatory References

NIH MedlinePlus overview

Eligibility and Restrictions for Use

Who Can and Cannot Use Sildenafil

Sildenafil eligibility is strictly defined by regulatory documents, focusing on patient population, age, and pre-existing health conditions. Use is primarily established for adults (18 years and older) for both Erectile Dysfunction (ED) and Pulmonary Arterial Hypertension (PAH), though pediatric use is approved only for the PAH indication.

Absolute Contraindications

Sildenafil is contraindicated and must not be used by patients taking organic nitrates or nitric oxide donors in any form, due to the risk of severe, sudden hypotension. Non-eligibility also applies to patients with a history of non-arteritic anterior ischaemic optic neuropathy (NAION), severe hypotension (BP < 90/50 mmHg), severe hepatic impairment (Child-Pugh Class C), or who have experienced a stroke or myocardial infarction within the last six months.

Restricted and Conditional Use

Use is not recommended for the ED indication in individuals under 18 years of age. Caution is required for patients with severe renal impairment and those with conditions predisposing them to priapism, such as sickle cell anemia. For women, the medicine is not indicated for ED, and use during pregnancy and lactation is generally not recommended due to insufficient data.

What should I know about interactions with other medicines?

Interactions with Other Medicines and Products

The official regulatory profile for Sildenafil is defined by interactions that affect plasma exposure and those that potentiate blood pressure lowering effects. Certain combinations are strictly contraindicated. This includes co-administration with Organic Nitrates (in any form) and the soluble guanylate cyclase stimulator Riociguat, due to the severe risk of symptomatic hypotension.

Pharmacokinetic and Pharmacodynamic Interactions

Interaction Type	Interacting Substance/Class	Official Regulatory Statement
Metabolic Inhibition	Potent CYP3A4 Inhibitors (e.g., Ritonavir)	These agents significantly increase Sildenafil plasma concentrations (exposure). Co-administration with Ritonavir mandates a specific maximum dosage restriction within a 48-hour period, as documented in labeling.
Metabolic Induction	CYP3A4 Inducers (e.g., Bosentan)	These agents decrease Sildenafil systemic exposure, which may require dose management.
Pharmacodynamic	Alpha-Blockers and certain Antihypertensives	Co-administration may result in additive blood pressure lowering effects that could lead to orthostatic symptoms.

Administration with a high-fat meal officially results in a reduced rate of absorption, delaying the time to reach peak plasma concentration. Sildenafil clearance is also reduced in patients with severe hepatic impairment, resulting in increased systemic exposure that can heighten the risk associated with other interacting substances.

Mechanism of Action

Sildenafil acts within signaling pathways to influence smooth muscle activity and vascular tension. It exerts its physiological effects by modulating an enzyme that controls the cellular concentration of a secondary messenger.

Enzyme-Mediated Signaling Inhibition

Sildenafil acts as a selective inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5), an enzyme present in the smooth muscle cells of certain tissues and vascular structures. By blocking PDE5, sildenafil prevents the hydrolysis of cyclic guanosine monophosphate (cGMP), a secondary messenger associated with smooth muscle relaxation. This engagement within the enzyme-mediated domain increases the levels of cGMP within the cell.

Augmentation of the cGMP Pathway

The molecule modifies the mechanistic cascade initiated by nitric oxide (NO). NO stimulates the production of cGMP. By preventing the breakdown of cGMP, sildenafil enhances and prolongs the action of this secondary signaling molecule, influencing the modulation of smooth muscle processes driven by this distinct pattern.

Vascular Smooth Muscle Relaxation

The sustained elevation of cGMP concentration within the cell ultimately results in the relaxation of vascular smooth muscle cells and a resultant vasodilation (widening of the blood vessel lumen). This physiological consequence is an increase in localized blood flow within specific tissues, resulting in an altered state of pathway activity shaping the drug's effect profile.

Dosage and Administration Information

Official Administration Guidelines for Sildenafil (Erectile Dysfunction)

The official instructions for sildenafil usage define a clear, as-needed procedural structure for oral administration based on standardized clinical protocols.

Dosing and Timing

The standard recommended oral dose for most patients is 50 mg taken as needed, approximately one hour before sexual activity. This drug may be taken anywhere from 30 minutes to 4 hours before the anticipated activity. The maximum recommended dosing frequency is once per day.

Dosing Parameter	Official Instruction (Adults)
Route of Administration	Oral (Tablet, Film-Coated Tablet, or Oral Suspension)
Standard Dose	50 mg as needed
Dose Adjustment	May be increased to a maximum of 100 mg or decreased to 25 mg based on effectiveness and tolerability
Maximum Frequency	Once per day

Special Conditions

Administration with Food: The medicine may be taken with or without food. However, taking it with a high-fat meal may lead to a delay in the onset of activity.
Age and Impairment: A lower starting dose of 25 mg should be considered for patients who are 65 years of age or older, or for those with severe renal impairment (creatinine clearance < 30 mL/min) or hepatic impairment.
Preparation: If using the oral suspension, the powder must be reconstituted according to the package directions, and the bottle should be shaken well for a minimum of 10 seconds before each use to ensure proper dosing.

These guidelines establish the standardized approach to using the medicine by setting specific time windows and dosage limits, ensuring consistent use.

Recent Clinical Evidence

Research Evidence / Overview of Studies

Phase 3 Trial Data

Studies have evaluated the effects of the drug on symptoms and disease activity. Findings on the magnitude and duration of effect have varied. Studies have investigated whether this medication may be useful in managing chronic pain.

Primary Endpoint: The main trials focused on changes in a validated patient-reported outcome measure (PROM) over 12 weeks.
Key Findings: The analysis indicated an association between the drug and a statistically different outcome in the PROM compared to the placebo group. The measured difference was reviewed by investigators to assess its clinical relevance.
Dosage Cohorts: Research has investigated the potential effects of varying dosages and whether different dosages may be associated with different measurable outcomes.

Combination Therapy Studies

A limited number of small-scale trials have investigated the drug when administered alongside an existing standard of care (SOC).

Comparative Evaluation: One key study investigated the outcomes observed when the drug was administered as combination therapy versus monotherapy. This research was structured to examine the potential for a different symptomatic profile.
Safety and Tolerability: Studies have explored potential interactions between this drug and Drug Y. The overall frequency of adverse events was recorded in all combination studies.

Pharmacokinetics and Follow-up Research

Research has examined the profile of the drug in long-term use. This research collected data on drug concentration over a one-year period.

Administration Effects: In some trials, the drug was administered with food. Study results were examined to determine the effect of concurrent food intake on observed adverse events.
Pediatric Studies: In younger participants, studies investigated whether the drug may be associated with a change in inflammation markers over time. The analysis was performed to see whether the observed changes were different from an older cohort.

Key Studies & References

Frequently Asked Questions (FAQ)

Common questions about Силденафил (FAQ)

Q: What is the difference between Силденафил and the brand name version?

A: Sildenafil is the generic medicine. Regulatory agencies require it to be bioequivalent to the brand name drug, meaning it contains the same active ingredient (sildenafil citrate) and regulatory standards establish that it should work in the same manner in the body. While the therapeutic effect is consistent, the inactive ingredients (such as fillers or coloring) may differ between generic and branded products.

Q: How long does the effect of Силденафил typically last?

A: According to official product information, the effect of Sildenafil for erectile dysfunction typically lasts up to 4 hours. Clinical studies suggest that the maximum concentration and effect are often observed early after administration. This duration is one factor that defines the maximum recommended dosing frequency of once per day.

Q: How quickly should I expect Силденафил to start working?

A: Sildenafil generally begins to work within 30 minutes after it is taken. Clinical data indicates that the peak effect, which represents maximum absorption, may occur rapidly when the drug is taken without food.

Q: Does the time of day I take Силденафил matter?

A: Official guidelines for Sildenafil for erectile dysfunction specify that it should be taken as needed in close relation to sexual activity. There is no regulatory requirement for the drug to be taken at a fixed time of day, such as only in the morning or only in the evening.

Q: Is the effectiveness of Силденафил different between generic and branded forms?

A: Generic Sildenafil is mandated by regulatory standards to demonstrate bioequivalence to the branded product. This is intended to ensure that the generic form is absorbed into the bloodstream at the same rate and extent, and is expected to deliver the same therapeutic effects as the brand name drug.

Q: Are there any known long-term side effects from using Силденафил?

A: Research has examined the profile of Sildenafil during long-term use and suggests the drug is generally well-tolerated over extended periods. Most adverse events reported, such as headache and flushing, are typically transient in nature. Official information emphasizes the importance of clinical supervision and monitoring during long-term use.

Q: What is the official description of Силденафил's safety profile?

A: The official safety profile is defined by common, usually transient, side effects like headache and flushing. Regulatory warnings are in place for rare but serious events, such as sudden vision or hearing loss and priapism. Additionally, the drug has absolute contraindications with certain medicines, including nitrates.

Q: Can people with prostate issues safely use Силденафил?

A: Official warnings note that for patients taking alpha-blockers (a class of drugs often used to treat prostate conditions), Sildenafil may cause additive blood pressure lowering effects. This is stated to potentially lead to symptoms such as dizziness or light-headedness, and requires caution.

Q: Are there guidelines regarding using Силденафил after recent surgery?

A: The official documentation specifically lists certain recent health events as contraindications. For instance, Sildenafil is contraindicated in patients who have experienced a stroke or myocardial infarction (heart attack) within the last six months.

Q: Why do doctors prescribe Силденафил for uses other than erection problems?

A: Sildenafil is formally approved by regulatory agencies for treating two specific indications: Erectile Dysfunction and Pulmonary Arterial Hypertension (PAH), which is a type of high blood pressure affecting the arteries in the lungs. Prescribers adhere to these approved uses.

Q: Does Силденафил treat the root cause of erection issues?

A: Sildenafil works by enhancing the physical process of an erection through promoting blood flow in response to sexual stimulation. The mechanism is focused on temporary blood flow regulation and is not described as treating the underlying cause of erectile dysfunction.

Q: What happens if I take Силденафил but don't experience sexual activity?

A: Official information states that Sildenafil requires sexual stimulation to work to cause an erection. If the drug is taken without sexual activity, the main intended effect for this purpose will not occur.

Q: Is Силденафил known to be habit-forming or addictive?

A: Available evidence indicates that Sildenafil is not associated with physical dependence or addiction. However, in cases of misuse, some medical texts suggest an individual could potentially develop a psychological dependence related to sexual performance.

Q: Does alcohol consumption impact how Силденафил works?

A: Clinical studies indicate that the co-administration of Sildenafil with alcohol may increase the risk of side effects such as dizziness, headache, or light-headedness due to potentially additive blood pressure effects.

Q: Can Силденафил be used by people with diabetes?

A: The effectiveness of Sildenafil for erectile dysfunction has been established in patients with diabetes. This patient group was included as part of the clinical trial data reviewed by regulatory agencies.

Q: Is there research on Силденафил use in people with kidney problems?

A: Pharmacokinetic studies have shown that Sildenafil clearance is reduced in patients with severe renal impairment. Regulatory documents reflect this research by advising a lower starting dose for this patient population.

Q: Does Силденафил interact with herbal supplements?

A: The FDA has issued public warnings concerning fraudulent herbal products promoted for sexual enhancement that illegally contain undeclared Sildenafil. This combination is described as posing a serious health risk, particularly when combined with nitrates.

Q: Why is it important to check if Силденафил contains lactose or other inactive ingredients?

A: It is standard regulatory practice for drug labeling to list all inactive ingredients (known as excipients). This information is provided to help patients with known sensitivities or allergies (such as lactose intolerance) ensure the product is suitable for their use.

Q: What happens if Силденафил does not work the first time it is used?

A: If Sildenafil is initially ineffective, prescribers often review several factors documented in official guidance. These include the patient's timing relative to sexual activity, whether there was sufficient sexual arousal, and the impact of high-fat meals, as these can reduce the drug's effectiveness.

Q: What are the general expectations about how many times Силденафил will be effective?

A: Pivotal clinical trials indicated that treatment was associated with a statistically different and improved outcome in patient-reported measures of erectile function compared to placebo. Success rates were reviewed by investigators for their clinical relevance.

How should Силденафил be stored and disposed of?

Storage and Disposal Requirements

Sildenafil must be stored strictly according to official regulatory guidelines to maintain its effectiveness and safety.

Requirement	Tablets	Oral Suspension
Temperature	Store below 30 C in original package.	Dry powder stored at 25 C.
In-Use Stability	N/A	Must be used or discarded within 30 days of mixing.
Handling Rules	Protect from moisture.	Do not refrigerate or freeze after mixing. Shake well before use.

All forms must be kept out of the reach of children in a tightly closed container. Do not flush unused medication unless specifically instructed by the FDA flush list. Dispose of expired or unwanted Sildenafil by utilizing a drug take-back program or following official guidelines to mix it with an undesirable substance (e.g., used coffee grounds) before placing it in the trash.

Силденафил