Ernafil

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Medically reviewed

Rosario Oropesa

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 Ernafil

What is Ernafil? Defining the Pharmaceutical Identity

Property Description
Active ingredient Sildenafil (as Sildenafil Citrate)
Form Oral tablet (Film-coated tablet)
Pharmacological class Phosphodiesterase Type 5 Inhibitor (PDE5 Inhibitor)
Common route Oral (by mouth)
Origin Synthetic compound

The Core Identity: Classification and Composition

Ernafil is a proprietary prescription-only medication developed by Actavis Ltd., corresponding to the synthetic active ingredient Sildenafil, most often formulated as Sildenafil Citrate. Pharmacologically, it is classified as a Phosphodiesterase Type 5 Inhibitor (PDE5 Inhibitor). This classification indicates the drug is a chemically precise agent targeting a specific biological enzyme.

The drug is a single-ingredient product, featuring Sildenafil as the sole therapeutic substance. It is routinely presented as an oral tablet (film-coated tablet) for oral administration, establishing a clear differentiation from its generic counterparts which may be positioned for alternative, often pulmonary, uses.


Function and General Therapeutic Purpose

The fundamental function of a PDE5 Inhibitor is to selectively improve local circulation by managing smooth muscle tone within the walls of blood vessels.

Ernafil achieves this effect by inhibiting the PDE5 enzyme, thereby preserving the essential signaling molecule cyclic Guanosine Monophosphate (cGMP). This process, recognized for its ability to mediate vascular response, promotes significant vasodilation (smooth muscle relaxation) and enhanced blood flow to target tissues. This mechanism is essential for achieving the drug’s overall therapeutic goal of addressing vascular conditions where improved localized circulation is critical. The medicine's overall purpose is thus to address physiological limitations where facilitating sustained and improved circulation is the therapeutic goal.

Regulatory References

  1. National Institutes of Health (NIH)
  2. MedlinePlus Drug Information
  3. European Public Assessment Report (EPAR) for Sildenafil
  4. European Public Assessment Report (EPAR) for Viagra (Sildenafil)
  5. EPAR for Sildenafil ratiopharm (Generic PDE5 Inhibitor)
  6. Role of cGMP in Sildenafil's Mechanism (NIH)

What side effects are possible with Ernafil?

Possible Side Effects and Safety Information

The safety profile of Ernafil (Sildenafil) is defined by officially documented adverse reactions, classified by their frequency and the physiological system they affect, as established in government regulatory documents.

Frequency-Classified Adverse Reactions

Adverse reactions are systematically categorized based on how often they appear in clinical use, ranging from Very Common to Rare. Headache is the most frequently documented adverse event, classified as Very Common. Common effects include flushing, dyspepsia, dizziness, and specific visual disturbances (such as blurred vision or color tinge to vision). Effects classified as Uncommon include rhinitis, nausea, and vomiting.

Systemic Safety Notes

Side effects have been reported across several System-Organ Classes (SOCs), notably affecting the Nervous System, Eye Disorders, and Vascular Disorders. Serious adverse reactions are explicitly documented in regulatory labeling. These include Priapism (a prolonged erection lasting four hours or more), sudden decrease or loss of hearing, and serious cardiovascular events, such as myocardial infarction.

Safety Considerations

The official safety information notes reduced drug clearance in specific patient populations, including older adults (age 65 and over), and individuals with severe renal or hepatic impairment. The medication is subject to safety restrictions and is contraindicated in patients using nitrates in any form due to the high risk of severe hypotension.

Overdose and Emergency Response

Overdose and when to seek help

The official regulatory profile indicates that overexposure to Ernafil is primarily defined by an exaggeration of the drug’s known effects, with incidence and severity increasing at higher doses. Documented clinical manifestations of overdose often include hypotension (abnormally low blood pressure), headache, flushing, and visual disturbances, such as the perceived blue-green color tinting known as cyanopsia.

Required Emergency Actions

Regulatory guidance mandates that immediate medical attention must be sought for any suspected overdose. The most serious and time-critical complication documented in the label is a prolonged erection (priapism), defined as an erection lasting more than four hours, for which emergency services must be contacted immediately.

Overdose Management

Management procedures described in official labeling consist of standard supportive measures and symptomatic treatment to address clinical signs. Regulatory documents state that no specific antidote is known for Sildenafil overexposure. Due to the high plasma protein binding of the active ingredient, renal dialysis is not expected to accelerate the clearance of the substance. Clearance of the drug is noted to be reduced in patients with severe renal or hepatic impairment, a factor relevant to clinical management.

Therapeutic Uses of Ernafil

What Ernafil Treats: Main Uses and Benefits

The therapeutic domains of Ernafil's active ingredient involve areas where additional symptomatic support is needed to address specific circulatory-driven functional limitations. This medicine is generally used to help with conditions that involve functional challenges, including Erectile Dysfunction (ED) and Pulmonary Arterial Hypertension (PAH).

Managing Impaired Erectile Functionality

This domain addresses the difficulty in achieving or sustaining an erection, which can interfere with daily comfort and sexual function. Ernafil is applied in addressing these symptom clusters that create noticeable physiological strain. The medication provides support that helps ease the overall symptom burden, contributing to comfort during periods of heightened symptoms.

Easing Symptoms of Pulmonary Vascular Resistance

Ernafil is also considered relevant for easing symptoms related to PAH, a condition where high pressure in the lung's arteries creates noticeable physiological strain. The medication is commonly used to help with symptoms that may become more disruptive, such as shortness of breath and fatigue associated with the condition. Its application in this context may assist with maintaining functional stability and may contribute to physical endurance during symptomatic phases.

Quick Fact: Support for Cardiopulmonary Symptoms
Common Clinical Context: Applied during phases when symptoms become more noticeable due to elevated pressure in lung blood vessels.
Key Benefit: Supports physical endurance and assists with maintaining functional stability.

Regulatory References

  1. NIH MedlinePlus overview

Eligibility and Restrictions for Use

Eligibility and Contraindications for Ernafil (Sildenafil)

Official regulatory documents define strict criteria for who can and cannot use Ernafil. Eligibility is primarily restricted to adult patients (18 years and older) for labeled conditions, such as Erectile Dysfunction (ED) and Pulmonary Arterial Hypertension (PAH). The medicine is formally contraindicated in several specific populations.

Absolute Prohibitions (Contraindications)

Classification Who Must Not Use (Examples)
Concomitant Medications Patients concurrently using any form of organic nitrates or nitrites, or Riociguat (a guanylate cyclase stimulator).
Comorbid Conditions Patients with recent history of myocardial infarction or stroke (within six months); severe hypotension (BP < 90/50 mmHg); known hereditary retinal disorders like retinitis pigmentosa; or vision loss due to NAION.

Age and Organ Function Restrictions

Ernafil is contraindicated for the ED indication in individuals under 18 years of age. Use is not recommended in patients with severe hepatic impairment or women who are pregnant or breastfeeding. Patients with severe renal impairment or conditions predisposing them to priapism should use the medicine only with specific caution, as defined in official labeling.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Ernafil (Sildenafil) has officially documented interaction patterns primarily concerning its metabolic pathway and its physiological effect on blood vessels.

Contraindicated Combinations

Co-administration with the following substances is strictly prohibited based on regulatory documents:

Contraindicated Entity Interaction Outcome
Organic Nitrates (any form) Severe, potentiated hypotensive effects (blood pressure lowering).
Riociguat Risk of severe symptomatic hypotension (low blood pressure).

Documented Pharmacokinetic Interactions

Ernafil is cleared from the body mainly by the CYP3A4 enzyme. Inhibitors of this enzyme increase Ernafil's systemic exposure, while inducers decrease it. Regulatory bodies advise on specific restrictions for co-administration with strong inhibitors.

Interacting Class Example Agents Interaction Effect
Strong CYP3A4 Inhibitors Ritonavir, Ketoconazole Significantly increase plasma exposure (up to 11-fold with Ritonavir).
CYP3A4 Inducers Rifampin, St. John's Wort May decrease Ernafil plasma levels.

Pharmacodynamic and Administration Cautions

Interactions that require careful administration include those with alpha-blockers, which may cause additive blood pressure-lowering effects that are most pronounced within four hours of dosing. Furthermore, co-administration with Ritonavir requires that the Ernafil dose must not exceed 25 mg within a 48-hour period.

Mechanism of Action

How Ernafil Works


Targeted Inhibition of the PDE5 Enzyme

Ernafil acts as a selective competitive inhibitor of the enzyme Phosphodiesterase Type 5 ( PDE5), which is concentrated in vascular smooth muscle. This inhibition prevents PDE5 from degrading the essential chemical messenger, cyclic Guanosine Monophosphate ( cGMP), leading to sustained elevated concentrations of cGMP.


Modulation of the NO/ cGMP Signaling Cascade

The PDE5 inhibition directly modulates the Nitric Oxide ( NO) signaling pathway by protecting cGMP from metabolism. The resulting accumulation of cGMP activates a chemical cascade that ultimately reduces intracellular calcium ( Ca^2+) activity, resulting in the deactivation of the smooth muscle's contractile machinery. Crucially, the mechanism is dependent on the physiological release of NO to initiate the cGMP synthesis.


Regulation of Localized Vascular Tone

The final mechanistic consequence is the profound relaxation of smooth muscle in the walls of targeted blood vessels, known as vasodilation. This physiological change significantly increases the volume and capacity for localized blood perfusion, which establishes the physiological basis for the drug's systemic actions.

Dosage and Administration Information

How Ernafil is Used

The usage of Ernafil (Sildenafil) is strictly governed by its official indication, resulting in two distinct administration protocols. This structure determines the dose, frequency, and duration of use.


Administration Routes and Dosing Patterns

The medicine is primarily administered via the oral route as a tablet or oral suspension. An intravenous (IV) injection is also approved for temporary use when oral intake is not feasible, specifically for the chronic maintenance regimen.

Usage Protocol Frequency and Timing Standard Dosing Range
As-Needed Use (Acute) Maximum of once per day. Taken approximately one hour before the activity. Starting dose of 50 mg, adjustable from 25 mg to a maximum of 100 mg per day.
Fixed Use (Chronic Maintenance) Three times a day (TID). Doses are typically spaced 4 to 8 hours apart. Standard oral dose is 20 mg. The equivalent IV dose is 10 mg per administration.

Administration Conditions and Adjustments

Ernafil tablets can be taken with or without food; however, consuming the dose with a high-fat meal may lead to a delay in the onset of its activity. When the oral suspension is used, it requires reconstitution with water according to specific instructions and must be measured accurately.

Standard protocols address dosing for specific populations. A lower starting dose (e.g., 25 mg for the as-needed regimen) is often considered for older adults (over 65) or for individuals with severe renal or hepatic impairment due to altered drug clearance. If a fixed-dose is missed, the protocol involves taking the next scheduled dose at its regular time.

Recent Clinical Evidence

Research evidence / Overview of Studies for Ernafil

Evidence for Use in Impaired Erectile Functionality

Research exploring Sildenafil was conducted in populations experiencing difficulty in achieving or sustaining an erection, and is primarily based on a large number of randomized, double-blind, placebo-controlled clinical trials (RCTs). These short-term studies were applied in research contexts involving fluctuating or unstable symptoms and have been thoroughly assessed in subsequent systematic reviews and meta-analyses that contribute to the broader evidence landscape.

In these studies, research examined changes measured during the study period, including patient-reported outcomes describing perceived discomfort and difficulty related to daily functioning. Findings describe patterns observed in the studies where the active ingredient was evaluated in men with erectile dysfunction (ED) of various causes. This research contributes to the broader evidence landscape and was reviewed during the regulatory process.

Evidence for Use in Pulmonary Arterial Hypertension (PAH)

The evidence base for Sildenafil was developed from rigorous, randomized, controlled trials that research examined specific outcomes reflecting daily functioning or activity level. The primary functional measure was the 6-Minute Walk Distance (6MWD), which is a key measurement used in trials. Studies monitored how symptoms evolved in the observed populations by tracking complex endpoints like the time to clinical worsening, which captures phases of heightened symptom activity or disease progression.

Long-Term Studies and Durability of Response

The research also includes long-term open-label extension studies for both indications, which were used to continue monitoring observed populations. However, for both indications, long-term outcomes are not fully established across the entire population, and data for extended outcomes beyond the specific follow-up durations used in the research remain insufficient to draw broad conclusions about the durability of response for every individual.

Areas of Research Uncertainty and Study Limitations

A key research limitation is that results apply only to the populations studied, meaning findings describe group patterns, not personal outcomes. Furthermore, comparative evidence is lacking for many potential combination therapies in PAH. For the pediatric PAH population, some official bodies have noted uncertainty and caution regarding long-term use at specific doses.

Key Studies & References

  1. Safety and Efficacy of Sildenafil in Children with Pulmonary Arterial Hypertension (The STARTS-1 and STARTS-2 Trials)

Frequently Asked Questions (FAQ)

Common questions about Ernafil (FAQ)


Q: How long does a dose of Ernafil stay in your system?

Official information indicates that Sildenafil, the active ingredient in Ernafil, and its main breakdown product are eliminated relatively quickly. They both have terminal half-lives of approximately four hours. This is the time it takes for the concentration of the medicine in the bloodstream to reduce by half.


Q: Can Ernafil make you feel sleepy or drowsy?

Drowsiness or somnolence is not typically listed as a common side effect in regulatory documents. However, official information does note that effects like dizziness and headache are frequently reported. Since these are central nervous system effects, they may potentially affect your alertness.


Q: Are there any foods or drinks I need to avoid while on Ernafil?

Official product information highlights a few considerations. Taking Ernafil with a high-fat meal may delay the absorption of the medicine, which means it could take longer to start working. Official warnings or cautions are typically given regarding the consumption of grapefruit or grapefruit juice, as it is known to interact with the way the body processes the medication, potentially increasing drug levels.


Q: Is there a generic version of Ernafil available?

Yes, regulatory and health information confirms that the active ingredient in Ernafil, known as Sildenafil, is widely available as a generic medication.


Q: Can taking Ernafil long-term cause any problems?

Official research often notes that long-term data may be insufficient to draw broad conclusions across all individuals. Nevertheless, specific long-term risks are addressed in regulatory warnings. These include the need for ongoing monitoring for known risks like priapism (a prolonged erection) and vision changes.


Q: Does alcohol make Ernafil less effective?

Alcohol consumption may add to the blood pressure-lowering effect of the medication. This combined effect can potentially cause increased symptoms like dizziness, headache, and light-headedness.


Q: Are children ever prescribed Ernafil?

Ernafil is not recommended for the Erectile Dysfunction (ED) indication in individuals under 18 years of age. Official findings during the review for the Pulmonary Arterial Hypertension (PAH) indication have included an observation of increased mortality risk with certain dosing in pediatric patients, leading to specific regulatory cautions regarding this population.


Q: Is the effectiveness of Ernafil consistent across all patient types?

Regulatory documents acknowledge that the response to the medication may vary among individuals. Variability can be influenced by factors such as age, the presence of conditions like liver or kidney impairment (which alter drug clearance), and the underlying cause of the condition being treated.


Q: Is Ernafil a controlled substance?

Ernafil (sildenafil) is classified as a prescription-only medication. However, it is not classified as a controlled substance according to official drug scheduling or regulatory frameworks.


Q: Can Ernafil worsen anxiety or mood?

Official information lists insomnia (difficulty sleeping) as a common adverse reaction for Ernafil. While effects on general anxiety or mood are not consistently reported as common, changes in sleep patterns or other central nervous system effects may influence an individual's mood.


Q: How does Ernafil compare to placebo in clinical trials?

Clinical trials for Ernafil established its efficacy by showing that it provided a statistically significant benefit compared to a placebo (a pill with no active medicine). Studies demonstrated improvements in key measures of functionality and patient-reported outcomes for the drug's labeled conditions when compared to placebo.


Q: Is it okay to take Ernafil at different times each day?

Official guidance distinguishes between two patterns of use. For as-needed use, the dose is taken only before activity, up to once per day. For fixed use (chronic), doses should be taken approximately 4 to 8 hours apart, which requires a consistent schedule.

How should Ernafil be stored and disposed of?

Storage Requirements

Ernafil (sildenafil) tablets must be stored at Controlled Room Temperature, defined as 20 C to 25 C (68 F to 77 F). The medication must be kept in its original container, which should be tightly closed to provide protection from moisture. Regulatory guidance states that the product must not be refrigerated or frozen. For safety, keep Ernafil out of the sight and reach of children.


Disposal Instructions

Unused or expired Ernafil must be disposed of according to local regulations. Official guidelines recommend utilizing a drug take-back program if one is available. If a take-back program is not accessible, the product may be mixed with an undesirable substance (e.g., used coffee grounds) in a sealed container and discarded in the household trash. It is advised not to dispose of Ernafil by flushing down the sink or toilet.

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

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