Virtus

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 Virtus

Quick Facts

Property Description
Active ingredient Sildenafil (Sildenafil citrate)
Form Tablet, Film-coated tablet (Oral preparation)
Pharmacological class Phosphodiesterase type 5 (PDE5) inhibitor
General purpose Enhancing blood flow in specific vascular beds
Origin Synthetic drug

What Type of Medicine is Virtus? (Identity and Classification)

Virtus is a synthetic, single-ingredient medicinal preparation categorized as a Phosphodiesterase type 5 (PDE5) inhibitor. This classification identifies the drug as a highly selective agent that modulates a single, defined enzyme system within the body, which is primarily responsible for regulating smooth muscle tone.

The medicine's identity is globally clinically recognized as a treatment supporting conditions reliant on enhanced localized blood flow. PDE5 inhibitors are designed to temporarily block the enzyme responsible for regulating vascular tone. This specific pharmacological action serves as the scientific basis for its clinical use.


Composition and Form: The Sildenafil Basis

The active core of Virtus is the synthetic chemical compound Sildenafil, typically incorporated as the citrate salt (Sildenafil citrate). This component constitutes the entire active profile of the medicine. The consistency of Sildenafil has been observed across decades of clinical use.

As an Oral preparation, Virtus is supplied for ingestion in the solid dosage form of a Tablet or a Film-coated tablet. Being a single-ingredient product, its precise effect is attributed to the defined properties of Sildenafil, a compound that is chemically manufactured rather than derived from natural sources.


General Purpose of the PDE5 Inhibitor Action

The general therapeutic purpose of the PDE5 inhibitor action is to enhance local smooth muscle relaxation, thereby promoting targeted increased blood flow in specific areas. This mechanism is intended to support the body's ability to achieve necessary hemodynamic changes.

This physiological effect is primarily utilized for conditions where localized vasodilation is beneficial. This includes supporting the body's natural response to stimulation necessary for treating erectile dysfunction and assisting in the management of elevated blood pressure within the arteries of the lungs, known as pulmonary arterial hypertension.

Regulatory References

  1. Sildenafil (StatPearls - NCBI Bookshelf)

What side effects are possible with Virtus?

Possible side effects and safety information

The official safety profile for Virtus (Sildenafil) is structured by governmental regulatory authorities based on the frequency and system-organ class affected. This section presents documented adverse reactions and specific safety constraints found in official labeling.


Frequency-Classified Adverse Reactions

The most commonly reported adverse events are often related to the drug's vasodilatory action, categorized by frequency:

Classification Examples of Reactions
Very Common (ge 1/10) Headache
Common (ge 1/100 to <1/10) Flushing, Dyspepsia (Indigestion), Nasal congestion, Visual disturbances (e.g., blurred vision)
Uncommon (ge 1/1000 to <1/100) Vomiting, Hypotension, Tachycardia, Rash, Myalgia (Muscle Pain), Back pain

Serious Adverse Reactions and Safety Constraints

Regulatory warnings highlight rare but clinically significant events and specific limitations. Serious adverse reactions reported in official documents include Priapism (prolonged erection), Non-arteritic Anterior Ischaemic Optic Neuropathy (NAION) leading to vision loss, and sudden loss of hearing.

Safety constraints define situations where the medicine should not be used. It is absolutely contraindicated with concomitant use of Nitrates or Nitric Oxide Donors due to the risk of severe hypotension. Caution is advised for patients with a history of recent myocardial infarction or stroke, specific hereditary retinal disorders, or severe hepatic impairment, as documented in official prescribing information. For patients on alpha-blockers, symptomatic hypotension is most likely to occur within four hours of dosing.

Overdose and Emergency Response

Virtus Overdose and when to seek help

Officially documented instances of Sildenafil overdosage indicate that manifestations generally correspond to the drug’s known adverse events, but occur with increased frequency and severity. Regulatory studies observing single doses up to 800 mg report that overexposure may present with exaggerated effects, including severe decreased blood pressure (hypotension) and syncope.

The regulatory labels state that specific clinical signs necessitate immediate emergency intervention to prevent irreversible harm. The patient must seek immediate medical assistance if an erection persists for longer than four hours (priapism), as this condition carries a risk of penile tissue damage and permanent loss of potency. Additionally, the patient must stop taking the medicine and consult a physician immediately for any sudden visual defect or sudden decrease or loss of hearing.

Management for overdosage is defined as symptomatic and supportive, as no specific antidote is known. Regulatory documents confirm that due to the compound’s high plasma protein binding, procedures such as renal dialysis are not expected to accelerate drug clearance. Specific population notes indicate that patients with severe hepatic or renal impairment may be more susceptible to overexposure effects due to reduced drug clearance.

Therapeutic Uses of Virtus

Virtus is applied across domains where additional symptomatic support is needed in two primary therapeutic areas. It is generally used to help with symptom clusters that create noticeable functional strain or interfere with daily functioning.

The medication is commonly used to help with conditions presenting with acute or episodic symptoms, including Erectile Dysfunction (ED), and conditions marked by increased physiological stress, such as Pulmonary Arterial Hypertension (PAH).

Easing Symptoms of Impaired Sexual Function

Virtus is applied when the inability to achieve or sustain functional penile rigidity creates noticeable physiological strain. The supportive therapeutic benefit may assist with maintaining functional balance when symptoms interfere with routine activities, contributing to improved comfort during symptomatic periods.

“This medication is considered relevant in contexts marked by increased discomfort and tension where short-term symptom management is appropriate.”

Quick Fact: Relevant for Symptoms Related to Impaired Penile Rigidity

Supportive Management of Pulmonary Arterial Hypertension (PAH)

The medication is relevant in managing symptoms linked to organ-specific functional stress, including reduced ability to exercise and shortness of breath. This supportive relief contributes to improved comfort during periods of heightened symptoms and may assist with maintaining functional balance for patients with this chronic condition.

Regulatory References

  1. NIH MedlinePlus Drug Information

Eligibility and Restrictions for Use

Eligibility Map: Who Can and Cannot Use Virtus (Codeine/Guaifenesin)

Official regulatory documents strictly define the patient populations for whom Virtus (a codeine and guaifenesin combination syrup) is approved, restricted, or prohibited.

Eligibility Scope Status in Regulatory Labeling
Populations Allowed Adults aged 18 years and older.
Populations Contraindicated Children and adolescents younger than 18 years (due to risk of severe breathing problems).
Patients with a known hypersensitivity or severe allergic reaction to codeine or guaifenesin.
Age-Related Restrictions Older adults may be more sensitive to side effects like drowsiness and must use with caution.
Condition-Specific Rules Contraindicated in certain acute respiratory conditions like severe respiratory depression or acute or severe bronchial asthma.
Caution is required for patients with severe kidney disease, liver disease, or a history of drug abuse.
Pregnancy/Lactation Status Not recommended during pregnancy, especially near delivery. Breastfeeding is not recommended while taking this medicine.

This medicine is restricted to the smallest effective dose for the shortest duration necessary to reduce the risk of misuse, addiction, and serious respiratory complications, as mandated by the regulatory bodies.

What should I know about interactions with other medicines?

Interactions with other medicines and products

The official interaction profile for this medicine (Sildenafil) is structured around agents that affect blood pressure and those that affect the body's clearance of the drug. The most critical interaction is with organic nitrates in any form (e.g., nitroglycerin, isosorbide dinitrate), and guanylate cyclase stimulators (e.g., riociguat), with co-administration being officially contraindicated due to the potential for a severe and dangerous drop in blood pressure.

Concomitant use with other Phosphodiesterase-5 (PDE-5) inhibitors is advised to be avoided. Caution is necessary when co-administering with alpha-blockers or other antihypertensive agents, as these combinations may also lead to potentiated hypotensive effects.

Additionally, drugs that significantly inhibit the CYP3A enzyme pathway, such as certain antifungal agents or HIV protease inhibitors, can increase the concentration of this medicine in the bloodstream, which may necessitate medical consultation regarding dosage. There is also documented information indicating a higher incidence of nosebleeds (epistaxis) in patients using this medicine with a concomitant oral vitamin K antagonist.

Mechanism of Action

How Virtus Works: Pharmacodynamic Mechanism

Virtus employs a dual mechanistic approach, primarily acting on two specific cellular targets. One component functions as a partial inverse agonist at the G-Protein Coupled Receptor ( GPCR-X) expressed on immune effector cells. This interaction reduces the basal activity of the receptor, leading to decreased signaling within the innate inflammatory pathway.

The second component is an allosteric non-competitive inhibitor of the intracellular Enzyme Y found in endothelial cells. Inhibition of Enzyme Y alters the structural conformation of the endothelium, maintaining the integrity of endothelial cell junctions. This synergistic process modifies early molecular steps that regulate mediator concentration.

The combined mechanistic effect of dampening immune signaling and altering the permeability properties of the vascular structures leads to an alteration of the local physiological state in targeted tissues. This process, which includes decreasing the rate of fluid and molecule extravasation, mechanistically links to the drug's observable physiological effects.

Dosage and Administration Information

Administration and Dosing Guidelines

The administration of Virtus (Sildenafil) is dictated by the specific therapeutic use, with distinct schedules and routes. The medicine is available in oral tablets (e.g., 25 mg, 50 mg, 100 mg for ED and 20 mg for PAH), oral suspension, and an intravenous injection for specialized use in Pulmonary Arterial Hypertension (PAH).


Dosing and Frequency

Indication Standard Regimen (Oral) Maximum Frequency Administration Notes
Erectile Dysfunction (ED) Starting dose of 50 mg, adjustable between 25 mg and 100 mg. Once per day. Taken as needed, 30 minutes to 4 hours before activity.
Pulmonary Arterial Hypertension (PAH) 20 mg three times daily (TID). Three times per day (TID). Doses must be separated by 4 to 6 hours. The intravenous dose is 10 mg TID.

Use Conditions and Adjustments

Virtus tablets may be taken with or without food for both approved uses; however, food may delay the onset of activity for the ED indication. The oral suspension form requires reconstitution with water and must be shaken well prior to each dose.

For specific populations, a lower starting dose of 25 mg is utilized for the ED indication. This applies to older adults (65 years and older), patients with severe renal impairment (creatinine clearance <30 mL/min), and those with hepatic impairment, due to altered drug clearance. Additionally, when used in conjunction with certain other medications, the starting dose may be reduced to 25 mg.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Virtus

Evidence for Use in Erectile Dysfunction (ED)

The research base for Virtus in adult men with Erectile Dysfunction (ED) is composed of a large number of randomized, controlled trials (RCTs). These studies were applied in examining patient groups with ED due to various factors, including those with underlying conditions like diabetes and men who had undergone radical prostatectomy. The research explored patient-reported experiences, such as the ability to achieve and maintain an erection as measured during sexual activity, often using standardized questionnaires that track changes in perceived discomfort and daily functioning. The controlled research exploring short-term symptom changes reported measurements of erectile function scores that were observed in the active treatment groups compared to the placebo control groups.

Evidence for Use in Pulmonary Arterial Hypertension (PAH)

The evidence for Virtus in Pulmonary Arterial Hypertension (PAH), a condition marked by functional limitations and high blood pressure in the lung arteries, was evaluated in medium-term randomized, placebo-controlled trials typically running for 12 to 16 weeks. The research examined outcomes reflecting daily functioning or activity level, primarily by monitoring the distance a patient could walk in a 6-minute walk test (6MWD). Other research monitored outcomes related to physiological strain or stress by tracking changes in the patient's WHO Functional Class. Longer-term extension studies were applied in research contexts involving fluctuating or unstable symptoms, tracking composite endpoints such as time to clinical worsening (which includes events tracked using a composite functional endpoint).

What is Still Uncertain About Virtus Research

The scientific research highlights several areas where certainty remains low or data are insufficient. The core efficacy data relies mostly on trials lasting three months or less, and long-term effects are not fully established through rigorous, controlled trials. Studies specifically comparing this agent against every other approved drug in its class or other therapeutic strategies are not extensive. Furthermore, specific research in children with PAH noted patterns of outcomes observed at higher doses, which prompted regulatory adjustments to the labeling for that specific group.

Key Studies & References Phosphodiesterase-5 inhibitors and prostate cancer: a systematic review and meta-analysis

Frequently Asked Questions (FAQ)

Common questions about Virtus (FAQ)


Q: Are there any foods or drinks that interact with Virtus?

Official information indicates that taking Virtus with a meal that is high in fat may slow down how quickly the medicine starts to work. This occurs because the rate at which the body absorbs the drug is reduced. Regulatory documents focus on the effect of a high-fat meal and do not typically list specific interactions with all common foods or non-alcoholic drinks.


Q: Does Virtus interact with alcohol?

Studies and official documents suggest that because Virtus has properties that relax blood vessels, combining it with alcohol may increase the chance of experiencing side effects. Due to the potential for additive blood pressure lowering effects, patients may experience symptoms like dizziness or lightheadedness when using this medication with alcohol.


Q: Is Virtus a type of antibiotic?

No, Virtus is not an antibiotic. According to the official classification, this medicine belongs to a class known as a Phosphodiesterase type 5 (PDE5) inhibitor. This means it works by modulating a specific enzyme in the body to help regulate localized blood flow.


Q: How quickly does Virtus usually start working?

The maximum concentration of Virtus in the bloodstream is usually reached within 30 to 120 minutes after taking a dose on an empty stomach. The median time to reach maximum concentration is reported as 60 minutes. Taking the dose with food may delay this onset.


Q: Can Virtus be taken with vitamins or herbal supplements?

Regulatory documents list key interactions with certain prescription drugs and enzyme inhibitors. While vitamins and most herbal supplements are not specifically listed, individuals using supplements, particularly those that may affect the liver or blood pressure, may need to consult a healthcare professional, as these areas are not fully covered in official drug interaction lists.


Q: Are there any long-term studies about Virtus?

Yes, some long-term extension studies, lasting up to several years, have been conducted, particularly in research for Pulmonary Arterial Hypertension (PAH). However, the core efficacy data used for regulatory approval of the main indications is primarily based on shorter controlled trials, such as those lasting 12 to 16 weeks.


Q: Will Virtus affect my ability to drive or operate machinery?

Side effects like dizziness, abnormal vision, or visual disturbances (including changes in color perception) have been reported with this medicine. These known side effects indicate that an individual’s ability to drive or operate machinery could be affected.


Q: What should I do if I experience an unexpected reaction to Virtus?

Regulatory warnings describe certain rare reactions that may require immediate cessation of the medication and prompt medical attention. These serious reactions include sudden loss of vision, sudden loss of hearing, or a prolonged erection lasting longer than four hours (priapism). Suspected side effects can also be officially reported to regulatory bodies.


Q: Does Virtus affect sleep?

Official adverse reaction reports from studies, particularly those involving the medicine’s use for pulmonary hypertension, indicate that insomnia (difficulty sleeping) has been reported as an adverse reaction in some patients.


Q: Is it possible to be allergic to Virtus?

Yes, official product information lists a known hypersensitivity (allergy) to sildenafil or any component of the tablet as a contraindication. This means the medicine should not be used by individuals with a history of severe allergic reactions to it.


Q: How does Virtus affect liver or kidney function?

Virtus is mainly removed from the body by the liver. Dose adjustments are recommended for individuals with severe renal or hepatic impairment because the medicine’s clearance is slower in these conditions. How the body processes the drug (pharmacokinetics) in patients with severely impaired liver function has not been fully studied in research.


Q: Is Virtus available as a generic medication?

Yes, the active ingredient in Virtus, which is sildenafil, is available in generic form. Generic versions of the medicine are supplied by multiple manufacturers.


Q: Can Virtus be taken if I have a heart condition?

Virtus has properties that can lead to mild decreases in blood pressure. Regulatory documents identify certain underlying heart conditions that require caution when considering the use of this medicine. The drug is not indicated for use if physical activity is inadvisable due to one’s cardiovascular status.


Q: What is the general timeframe to expect results from Virtus?

For conditions requiring chronic use, such as Pulmonary Arterial Hypertension (PAH), clinical studies established the effectiveness of the drug over typical short-term periods of 12 to 16 weeks. In studies, the medicine demonstrated improvements in exercise ability and a delay in clinical worsening over this timeframe when compared to placebo.


Q: Is Virtus used for any other conditions besides its main purpose?

According to official regulatory indications, Virtus is approved for the treatment of two specific conditions: Erectile Dysfunction (ED) and Pulmonary Arterial Hypertension (PAH). There are no other conditions for which the drug is formally indicated.


Q: Is Virtus safe for pregnant or breastfeeding individuals (descriptive only)?

Official information states that Virtus is not indicated for the treatment of Erectile Dysfunction in females. For the use in Pulmonary Arterial Hypertension, data from controlled studies in pregnant women is limited. It is not known if the drug passes into human breast milk, and regulatory information notes that caution should be considered regarding its use while breastfeeding.


Q: What is the difference between the different doses of Virtus?

The dosage of Virtus is determined by the specific condition being treated. Higher doses are typically used for Erectile Dysfunction on an as-needed basis. Lower, more frequently repeated doses are prescribed for the continuous treatment of Pulmonary Arterial Hypertension.


Q: Why do some people say Virtus did not work for them?

Official research reports show that the effects of the medicine can vary among patients. Not all individuals in clinical trials experience an improvement in their condition when compared to placebo. The medicine's effectiveness can also depend on specific underlying medical conditions and the use of other medications.


Q: Is it normal to feel dizzy or tired when first starting Virtus?

Dizziness is listed as a common adverse reaction reported in clinical trials. Fatigue or tiredness is not listed as a common reaction, but is a potential symptom related to other common effects such as a change in blood pressure.


Q: Is Virtus used to prevent a condition or to treat it?

According to the approved indications, Virtus is used for the treatment of Erectile Dysfunction and the treatment of Pulmonary Arterial Hypertension (PAH). For PAH, the treatment has been shown to improve exercise ability and help delay the worsening of the disease.


Q: Are there any known drug-disease interactions with Virtus?

Yes, official warnings advise that caution is necessary with certain pre-existing conditions that are known to interact with the drug. These include conditions like recent heart attack or stroke, specific hereditary retinal disorders, and pulmonary veno-occlusive disease. These warnings are used to help healthcare professionals determine the appropriate use of the medicine.


Q: Is Virtus approved in countries outside the US?

Yes, the active ingredient sildenafil is globally approved for use. Regulatory agencies such as the European Medicines Agency (EMA) have authorized this medicine for use across the European Union, and it is recognized worldwide.


Q: Is it common for people to have no side effects from Virtus?

Yes, based on clinical trial data, the majority of patients did not report the most commonly listed adverse reactions. For instance, the most common side effects, such as headache and flushing, were reported by less than 10% of patients in studies.


Q: How common are gastrointestinal side effects with Virtus?

Official adverse reaction lists show that some gastrointestinal effects are common, while others are less frequent. Dyspepsia (indigestion) is listed as a common effect, while vomiting is reported as an uncommon effect in clinical trials.


Q: What are the eligibility requirements for being prescribed Virtus?

The medicine is contraindicated (should not be used) if an individual is taking any form of organic nitrates or specific guanylate cyclase stimulators, or if they have a known allergy to the drug. The determination of whether the medicine is appropriate for a specific individual is made by a healthcare professional, based on that individual’s health status and medications.

How should Virtus be stored and disposed of?

How to Store and Dispose of Virtus (Sildenafil)

Virtus must be stored according to regulatory labeling to maintain quality and ensure safety.


Storage Conditions

Official documents mandate storage at Controlled Room Temperature, typically 20 C to 25 C (68 F to 77 F). The product must be protected from moisture and freezing. Keep the medicine in its child-resistant container and out of the sight and reach of children.


Disposal Requirements

Unused or expired Virtus must be discarded in accordance with local requirements. The medicine should be taken to a formal drug take-back program where available. Do not dispose of the tablets by flushing them down a toilet or pouring them down a sink to avoid environmental release. If a take-back program is unavailable, mix the tablets with an unappealing substance, place the mixture in a sealed container, and dispose of it in the household trash.

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

Available in countries:

Equivalent of Virtus found in:

A-Z Index: