Sildenon

Quick links to important sections

Medically reviewed

Marina Burgos

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Sildenon

Quick Facts

Property Description
Active Ingredient Sildenafil citrate (Sildenafil)
Form Film-coated tablet
Pharmacological Class Phosphodiesterase type 5 (PDE5) Inhibitor
General Purpose To facilitate local blood flow
Origin Synthetic compound

What Type of Medicine is Sildenon?

Sildenon is a synthetic, prescription-only pharmaceutical product containing the active ingredient Sildenafil, and is classified as a selective Phosphodiesterase type 5 (PDE5) Inhibitor. This classification establishes Sildenon within a distinct group of medications that operate by targeting one specific biological pathway in the body. The active component, Sildenafil, is a synthetic compound, a piperazine derivative created through chemical synthesis. Its identity and pharmacological action as a PDE5 inhibitor mean the drug works by influencing a defined enzyme system to mediate a specific physiological response. For patient administration, Sildenon is formulated as a film-coated tablet designed for oral ingestion.

Composition and Origin of Sildenon

The pharmacological identity of Sildenon is derived from its single active ingredient, Sildenafil citrate, a synthesized chemical salt. It is designated as a single active ingredient product, containing Sildenafil alongside standard pharmaceutical excipients necessary for forming the solid oral vehicle (tablet). The active ingredient's profile is characterized by its selectivity against the target enzyme. Its route of administration is oral, designed for absorption from the gastrointestinal tract into the bloodstream. The chemical structure of the molecule enables this selective action on the PDE5 enzyme.

General Purpose and Action of PDE5 Inhibitors

The primary functional goal of Sildenon is to enhance localized blood flow by mediating the relaxation of smooth muscle tissue in specific vascular beds, a process utilized for addressing conditions rooted in inadequate circulation. Sildenon achieves this by temporarily blocking the PDE5 enzyme, which consequently preserves the concentration of the signaling molecule, cyclic guanosine monophosphate (cGMP). By protecting cGMP from degradation, Sildenon facilitates vasodilation (vessel widening). This targeted action forms the foundation of its general therapeutic utility, supporting physiological functions that rely on sufficient local circulation.

What side effects are possible with Sildenon?

Possible Side Effects and Safety Information

The safety profile of Sildenon is structured by regulatory standards, with adverse reactions formally categorized by frequency and the body's System Organ Class (SOC). As a PDE5 Inhibitor, many common effects are linked to its vasodilatory properties, resulting in transient changes.


Official Frequency Classifications

The most frequently reported adverse reactions are classified as Very Common (occurring in 10% of patients) and include headache and flushing. Reactions classified as Common (occurring in 1% - 10% of patients) often involve the nervous system or vision, such as dizziness, visual colour distortions, and vision blurred, alongside dyspepsia and nasal congestion.


Serious and Rare Adverse Reactions

Certain clinically significant events are classified as Rare (0.01% - 0.1% of patients) and include Non-arteritic Anterior Ischemic Optic Neuropathy (NAION), a cause of sudden vision loss, and priapism (a prolonged erection lasting over four hours). Rare cardiovascular events such as myocardial infarction and sudden cardiac death have also been reported in temporal association with its use.


Population-Specific Safety Constraints

The medication is contraindicated in patients with severe hepatic impairment or a history of vision loss due to NAION. Use is also absolutely contraindicated with any form of nitrate or nitric oxide donor due to the serious risk of severe blood pressure drop. Caution is required in patients with specific conditions predisposing to priapism or in those with certain severe cardiovascular risk factors.

Overdose and Emergency Response

Overdose and when to seek help

The Sildenon overdose profile, as documented in government regulatory labeling, is primarily defined by an exaggeration of the drug's known vasodilatory effects. Documented clinical manifestations observed at doses exceeding recommended levels include intensified headache, flushing, and dizziness, along with dyspepsia, nasal congestion, and various visual disturbances. These effects are recognized as amplified symptoms stemming from the drug's core physiological action.


Emergency Action and Supportive Management

The most serious, potentially life-threatening outcomes require urgent care, specifically profound hypotension (low blood pressure), syncope (fainting), and other signs of cardiovascular instability. Regulators unequivocally state that immediate medical attention must be sought for any suspected overdose. Management is strictly restricted to symptomatic and supportive treatment because official labeling confirms that no specific antidote is known. Due to the drug’s high plasma protein binding, hemodialysis is not expected to accelerate clearance from the body. Patients with severe renal impairment or hepatic impairment may experience prolonged effects following an overdose because drug clearance is officially noted as reduced in these conditions.

Therapeutic Uses of Sildenon

What Sildenon treats: Main Uses and Benefits

Sildenon is applied across domains where additional symptomatic support is needed, primarily used in conditions where localized physiological stress is present. This medication is commonly used to manage symptoms in two primary therapeutic areas: erectile dysfunction (ED) and Pulmonary Arterial Hypertension (PAH).


Addressing Erectile Insufficiency

Sildenon is applied in addressing ED, a condition where symptoms are related to physical discomfort and functional strain. The benefit provided is functional, and the medication may support the patient's efforts to achieve or maintain an erection for satisfactory sexual intercourse, which contributes to easing the associated psychological burden and impact on intimacy.

Management of Pulmonary Arterial Hypertension (PAH)

The medication is also used in the management of PAH, a condition marked by heightened symptoms associated with systemic imbalance in the lung arteries. Sildenon is relevant for easing symptoms that interfere with daily functioning, such as shortness of breath and reduced exercise capacity. This supportive therapy is applied in clinical settings that involve acute or unstable symptom patterns.


Quick Fact: Support for Symptoms Interfering with Daily Functioning
Relief Target Symptoms related to localized functional stress and systemic imbalance.
Scenario Relevant in contexts of short-term functional support and long-term systemic management.
Patient Benefit Supports stability and contributes to easing the overall symptom load.

Regulatory References

  1. NIH MedlinePlus overview on Sildenafil

Eligibility and Restrictions for Use

Official Eligibility and Restrictions

Sildenon's eligibility profile is strictly defined by regulatory authorities and is dependent on the patient's age, underlying health status, and concurrent medication use.


Populations Who Must Not Use Sildenon (Contraindicated)

Sildenon is formally contraindicated in patients with the following conditions or circumstances:

  • Concomitant use of any form of organic nitrates or nitric oxide donors (due to risk of severe hypotension).
  • Concomitant use of soluble guanylate cyclase (sGC) stimulators (e.g., riociguat).
  • Severe cardiovascular disorders where sexual activity is inadvisable (e.g., unstable angina, severe cardiac failure).
  • History of non-arteritic anterior ischaemic optic neuropathy (NAION) or certain hereditary degenerative retinal disorders (e.g., retinitis pigmentosa).
  • Severe hypotension (resting blood pressure typically below 90/50 mmHg) or severe hepatic impairment (Child-Pugh Class C).

Age-Related and Conditional Eligibility

Population Group Regulatory Eligibility Status
Pediatric (Under 18) Not indicated for Erectile Dysfunction use.
Pediatric (PAH) Not recommended due to an official warning of increased mortality with increasing dose in a long-term trial.
Older Adults (65+) Eligible, but a reduced initial dose is officially considered for the ED indication due to reduced drug clearance.
Severe Renal Impairment Requires special consideration for a reduced initial dose.

Use is also conditional and requires caution in patients with conditions predisposing to priapism (e.g., sickle cell anemia) and in pregnant or lactating women due to limited data and excretion into breast milk.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Sildenon's interaction profile is strictly defined by government regulatory documents and is structured around pharmacokinetic and pharmacodynamic mechanisms. Officially documented combination restrictions are summarized below.


Documented Combination Restrictions

Classification Interacting Entity Official Regulatory Statement
Contraindicated Organic Nitrates (e.g., Nitroglycerin) Co-administration is prohibited due to the risk of severe hypotension.
Contraindicated Guanylate Cyclase Stimulators (e.g., Riociguat) Co-administration is prohibited due to the risk of symptomatic hypotension.
Requires Dose/Timing Restriction Strong CYP3A4 Inhibitors (e.g., Ritonavir) These agents increase Sildenafil plasma exposure. A maximum dose and specific timing separation must be observed.
Use with Caution Alpha-Blockers Potential for additive blood pressure lowering effects. Initiation should occur at the lowest Sildenon dose.

Pharmacokinetic and Substance Interactions

Sildenon is primarily cleared by the Cytochrome P450 enzyme CYP3A4. Agents that induce or inhibit this enzyme directly affect Sildenafil exposure; inhibitors increase plasma levels, while inducers (e.g., Rifampin) decrease them. A high-fat meal officially reduces the rate of Sildenon absorption. Furthermore, higher Sildenafil plasma concentrations are documented in populations with severe renal impairment and hepatic impairment.

Mechanism of Action

Selective Inhibition of the PDE5 Enzyme System

Sildenon's active ingredient, Sildenafil, acts as a highly selective inhibitor of the enzyme Phosphodiesterase type 5 (PDE5). This enzyme is responsible for the rapid breakdown of the second messenger cyclic Guanosine Monophosphate (cGMP). Sildenafil's selective molecular action prevents this breakdown, thereby preserving and amplifying the cGMP signal.


NO-Dependent Vascular Pathway Modulation

The drug's mechanism is functionally contingent upon the body's natural Nitric Oxide (NO)-cGMP pathway. The elevated concentration of cGMP initiates a biochemical cascade that decreases smooth muscle contractile activity in arterial smooth muscle. This cellular event results in vasodilation and a subsequent facilitation of local tissue perfusion. This action is limited to regions where the natural NO signal is released, meaning the drug acts as an enhancer, not an initiator, of the Nitric Oxide (NO) signaling cascade.

Dosage and Administration Information

How Sildenon is Used: Official Administration Guidelines

Sildenon (Sildenafil) is administered via different protocols depending on the condition being addressed: Erectile Dysfunction (ED) or Pulmonary Arterial Hypertension (PAH). Established administration guidelines define the route, dose, and frequency for each authorized use.


Official Dosing and Frequency

Indication Administration Route Standard Dosing Regimen Maximum Frequency
ED Oral (Tablet) Starting dose is 50 mg, adjustable between 25 mg and 100 mg. Once per day
PAH Oral (Tablet/Suspension) 20 mg taken three times a day (TID), approximately 4 to 6 hours apart. Three times per day
PAH Intravenous (IV) Injection 10 mg administered TID, used when the oral route is not feasible. Three times per day

Contextual Use and Adjustments

Sildenon tablets for ED are taken as needed and may be administered with or without food, though taking them with a high-fat meal can delay their onset of action. The action of Sildenon for ED requires sexual stimulation. For patients receiving the continuous PAH regimen, a dose adjustment may be necessary for specific populations; for example, a lower starting dose of 25 mg should be considered for ED in older adults (≥ 65 years) or those with severe renal or hepatic impairment. The IV form for PAH is administered as a bolus injection for a short duration when the oral route is temporarily restricted.

Recent Clinical Evidence

Research evidence / Overview of studies for Sildenon

The research evaluating Sildenon (Sildenafil) has been conducted primarily through highly controlled clinical trials and subsequent systematic reviews, providing a structured overview of the evidence base in specific patient populations. The evidence summarized here focuses strictly on the data reviewed by regulators for the medicine's approved uses.


Evidence from Clinical Trials for Erectile Dysfunction

The primary body of evidence for Sildenon for use in erectile dysfunction (ED) comes from numerous short-term Randomized Controlled Trials (RCTs), many of which were double-blind and placebo-controlled. These studies were applied in research exploring how symptoms change over time and generally compared the drug compound against a placebo. Research was conducted among adult men with functional limitations related to erectile insufficiency, including those with associated conditions such as diabetes mellitus and patients who had undergone prostate surgery.

Studies monitored outcomes related to physical discomfort and functional imbalance, using standardized tools like the International Index of Erectile Function (IIEF) score. Data show patterns related to changes in reported outcomes of achieving and maintaining an erection during the short-term observation window. The overall evidence base for this indication is considered by regulatory bodies to be of a High level, derived from the consistency of findings across the core clinical evaluation studies.


Evidence from Clinical Trials for Pulmonary Arterial Hypertension (PAH)

Research examined Sildenon was studied for patients diagnosed with Pulmonary Arterial Hypertension (PAH). Initial evidence was based on core Randomized Controlled Trials (RCTs), with subsequent post-marketing studies mandated to monitor specific long-term outcomes. Studies explored outcomes reflecting daily functioning and activity level, primarily through the 6-Minute Walk Distance (6MWD) and by tracking the time until a clinical worsening event occurred.

For the functional and clinical worsening endpoints in adults, the evidence base is assessed as having a High level. However, data show patterns related to all-cause mortality that are still emerging, and certainty remains lower for this specific outcome, with the evidence level classified as Moderate. Direct head-to-head comparative evidence is lacking against all other approved active treatments.


Key Limitations and Areas of Research Uncertainty

One significant limitation is that the early trials often had follow-up durations that were limited, especially for assessing long-term health outcomes. Additionally, controversial findings emerged from extension studies in the pediatric population with PAH, resulting in differing regulatory cautions across international health agencies regarding long-term use in children. The research provides context but not individual predictions, and findings describe group patterns, not personal outcomes.

Key Studies & References

  1. Randomized trial of sildenafil for the treatment of erectile dysfunction in spinal cord injury. Sildenafil Study Group
  2. Treatment of Erectile Dysfunction with Sildenafil (References IIEF outcomes)

Frequently Asked Questions (FAQ)

Common questions about Sildenon (FAQ)


Q: Is Sildenon the same kind of medicine as other drugs used for the same purpose?

A: Sildenon is classified by regulatory bodies as a Phosphodiesterase type 5 (PDE5) Inhibitor. This classification means it belongs to a group of medications that work by targeting the specific PDE5 enzyme in the body. Other medicines used for similar conditions may also fall into this same pharmacological class.

Q: What is the main difference between Sildenon and other treatments that people talk about online?

A: Official regulatory studies primarily examine Sildenon's effectiveness by comparing it against an inactive placebo. Evidence indicates that studies often do not include direct, head-to-head comparisons against all other approved treatments. This means official documents focus on the drug’s intended effect rather than its relative performance compared to alternatives.

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

A: Clinical pharmacology data for the erectile dysfunction (ED) indication indicates that the active component typically reaches its highest concentration in the bloodstream approximately one hour after ingestion. However, the time it takes to start working can vary among individuals, potentially ranging from 30 minutes to up to 4 hours.

Q: What is the typical amount of time Sildenon stays active in the body?

A: The amount of time Sildenon remains active is described by its half-life in official clinical pharmacology data. In healthy adults, the active component has a terminal half-life typically ranging from 3 to 5 hours. This figure describes the time needed for the amount of medicine in the body to be reduced by half.

Q: Does Sildenon affect my blood pressure?

A: Yes, Sildenon is a vasodilator, meaning it causes blood vessels to widen and results in a mild and temporary drop in the body's systemic blood pressure. Official information advises caution, as this effect can be more pronounced when Sildenon is taken alongside certain blood pressure-lowering medications or with alcohol.

Q: Can taking Sildenon cause vision changes, and are they temporary?

A: The official safety profile notes common vision changes, such as blurred sight or a temporary blue tinge to vision. A rare but serious event, Non-arteritic Anterior Ischemic Optic Neuropathy (NAION), has also been reported, which involves sudden vision loss. Official patient counseling indicates that immediate emergency medical attention is necessary if this rare, serious side effect occurs.

Q: I heard Sildenon can interact with grapefruit. Is this true?

A: Official regulatory data advises caution regarding this potential interaction. Grapefruit and its juice may interfere with the enzyme in the liver that is responsible for breaking down Sildenon. This interference can result in increased levels of Sildenon in the blood, which may raise the risk of experiencing side effects.

Q: What happens if I take Sildenon with alcohol?

A: Regulatory documents advise caution regarding the consumption of alcohol while using Sildenon. Taking the medicine with alcohol may increase the risk of experiencing low blood pressure. This combination may also potentially worsen common vasodilatory side effects like dizziness, flushing, and headaches.

Q: Is Sildenon safe for people with heart conditions?

A: Sildenon is formally prohibited, or contraindicated, for use in patients with certain severe cardiovascular disorders. This restriction applies when a medical professional advises against physical activities, such as sexual activity, due to conditions like unstable angina or severe cardiac failure.

Q: Does Sildenon affect fertility or ability to have children?

A: According to official regulatory guidance, clinical studies in men have shown no resulting changes to sperm characteristics. For women, the product information does not indicate clear evidence that Sildenon reduces fertility. There is a lack of long-term data for use during pregnancy or lactation.

Q: Is it true that Sildenon was originally studied for a different medical use?

A: Yes, official drug references and historical data indicate that the active component in Sildenon was originally studied for a different medical use. It was initially researched for its potential role in treating cardiovascular problems, specifically chest pain, before its primary uses were identified.

Q: Can Sildenon interact with common over-the-counter pain relievers?

A: Regulatory documents advise patients to inform their healthcare provider about all prescription and over-the-counter (OTC) medicines they use. While general warnings about non-specific OTCs exist, official product information does not list explicit interactions with common, non-NSAID pain relievers.

Q: What if a user experiences a severe, rare side effect like priapism?

A: If a user experiences a severe, rare side effect called priapism, which is a prolonged erection lasting longer than four hours, official patient counseling indicates that this situation necessitates immediate medical intervention. The official labeling advises patients that emergency medical care is required for this event.

Q: Why is Sildenon restricted to prescription-only status?

A: Sildenon is restricted to prescription-only status because of the critical need for medical supervision. This is necessary to properly assess a patient for strict contraindications, such as the use of nitrates, and to manage the risk of serious side effects like severe hypotension or priapism.

Q: What if I accidentally use too much Sildenon?

A: In the case of an accidental overdose, official patient information indicates that the individual is advised to seek guidance from a doctor or emergency services. Overdosing may lead to an increase in the frequency and severity of the drug’s common side effects.

Q: Does Sildenon interact with blood thinners?

A: Regulatory documents advise caution regarding co-administration with blood thinners, which are also known as anticoagulants (e.g., warfarin). While Sildenon is not itself a blood thinner, reports indicate a possible increased risk of bleeding complications and nosebleeds when these medications are used together.

How should Sildenon be stored and disposed of?

Official Storage and Disposal Instructions for Sildenafil

Sildenafil tablets and powder for oral suspension require specific storage conditions to maintain stability and safety, as mandated by regulatory documents.


Storage Requirements

  • Temperature: Store at controlled room temperature, 20 C to 25 C (68 F to 77 F), away from excess heat and moisture. Do not store the medicine in a bathroom.
  • Protection: The product must be stored out of the sight and reach of children and kept in its original, tightly closed container.
  • Stability Limit: Any prepared (reconstituted) oral suspension must be discarded 60 days after the date it was mixed.

Disposal Instructions

Unused or expired Sildenafil must be disposed of properly according to federal and local environmental requirements. The medication must not be flushed down the toilet or poured into a drain to prevent environmental contamination.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

Available in countries:

Equivalent of Sildenon found in:

A-Z Index: