Modrasil

Quick links to important sections

Medically reviewed

Laura Arias

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 Modrasil

What is Modrasil?

Modrasil is a pharmacological agent categorized as a wakefulness-promoting medication. It is primarily utilized to manage excessive daytime sleepiness associated with specific chronic sleep disorders. Unlike traditional stimulants, Modrasil is designed to target specific areas of the brain that regulate the sleep-wake cycle, helping individuals maintain a state of alertness during their required waking hours.

Mechanism of Action

The precise biological mechanism by which Modrasil exerts its effects is not fully understood. However, research indicates that it interacts with neurotransmitters in the central nervous system. It is believed to inhibit the reuptake of dopamine by binding to the dopamine transporter, thereby increasing extracellular dopamine levels. Additionally, it may influence other chemical messengers, such as norepinephrine, serotonin, and orexin, which play vital roles in maintaining arousal and wakefulness.

Primary Applications

Modrasil is indicated for the treatment of sleep-related conditions where maintaining alertness is a clinical priority. These conditions include:

  • Narcolepsy: A neurological disorder characterized by the brain's inability to regulate sleep-wake cycles normally, often resulting in sudden sleep attacks.
  • Obstructive Sleep Apnea (OSA): Used as an adjunct therapy to address persistent sleepiness that remains despite the use of primary treatments like CPAP machines.
  • Shift Work Disorder (SWD): A circadian rhythm sleep disorder that affects individuals who work non-traditional hours, leading to excessive sleepiness during work shifts and insomnia during rest periods.

Characteristics and Classification

Modrasil is distinguished from other stimulants by its lower potential for jitteriness or the "rebound effect" often seen with older medications. It is characterized by a profile that promotes a steady state of wakefulness rather than an acute rush of energy. While it helps manage the symptom of excessive sleepiness, it is important to note that Modrasil is not a replacement for natural sleep and does not cure the underlying sleep disorders.

Regulatory References

  1. NIH StatPearls
  2. European Medicines Agency
  3. synthetic
  4. Phosphodiesterase type 5 (PDE5) Inhibitors
  5. single-ingredient product
  6. enzyme inhibitor
  7. dosage form(s)
  8. oral tablet
  9. injectable solution
  10. smooth muscle relaxation
  11. vasodilation
  12. PDE5
  13. cyclic guanosine monophosphate (cGMP)
  14. blood flow

What side effects are possible with Modrasil?

Possible side effects and safety information

The safety profile of Modrasil (Sildenafil) is structured by government regulatory agencies using classifications based on the frequency and the System-Organ Class (SOC) affected. The most frequently documented adverse reactions, classified as Very Common in official labeling, include Headache. Side effects classified as Common include Flushing, Dyspepsia, Nasal congestion, Dizziness, and certain Visual disturbances, such as visual color distortions.

Documented Serious Adverse Reactions

The regulatory documents highlight rare but serious adverse reactions that have been reported post-marketing. These include Priapism (a prolonged erection), Non-arteritic anterior ischaemic optic neuropathy (NAION), and Sudden decrease or loss of hearing. Serious cardiovascular events, such as Myocardial infarction or Ventricular arrhythmia, have also been reported in temporal association with use.

Safety Constraints and Special Populations

Official safety information defines specific constraints on use. The medicine is contraindicated in patients concurrently using organic nitrates or nitric oxide donors due to the risk of severe hypotension. Contraindications also apply to individuals with severe hepatic impairment or a history of NAION. Specific safety notes exist for certain groups; for example, a high-dose study in pediatric patients with Pulmonary Arterial Hypertension (PAH) indicated an increased mortality risk with chronic use, leading to a regulatory recommendation against its use in this setting. Some documented adverse events, such as headache, may be more frequently observed at the start of treatment.

Overdose and Emergency Response

A Modrasil (Sildenafil) overdose is officially documented as presenting through an exaggeration of the drug's known pharmacological effects, primarily due to extended vasodilation. Clinical manifestations observed in regulatory reporting include severe systemic effects such as hypotension (low blood pressure), pronounced flushing, intense headache, dizziness, tachycardia (increased heart rate), and dose-related visual perception changes. Serious cardiovascular events like myocardial infarction and ventricular arrhythmia have been reported in temporal association with use.

Immediate medical assistance is required for any suspected overdose. The most critical, time-sensitive manifestation requiring immediate attention is a prolonged erection (priapism) lasting longer than four hours. Regulators emphasize that failure to seek emergency treatment for this condition can result in penile tissue damage and permanent loss of potency. Patients must also seek immediate consultation upon experiencing a sudden decrease or loss of vision or hearing.

Official management for Sildenafil overexposure focuses entirely on symptomatic treatment and supportive measures, as no specific antidote is known. Regulatory guidelines also note that patients with severe hepatic or renal impairment may be at heightened risk of overexposure due to their reduced ability to clear the drug from the body.

Therapeutic Uses of Modrasil

What Modrasil treats: Main Uses and Benefits

Modrasil may be part of symptomatic management for Erectile Dysfunction (ED), a condition where individuals experience symptoms related to physical discomfort and functional difficulty in achieving or maintaining a penile erection. The medication is used in conditions involving episodic or fluctuating manifestations. This medication is applied in symptomatic-driven clinical presentations, often associated with chronic conditions like diabetes or post-surgical changes, where functional stability may become affected. The primary therapeutic benefit helps address symptom clusters that may become intense or disruptive, assisting with maintaining functional stability in situations where patients experience functional strain.


Modrasil plays a role in managing symptoms across multiple domains, including its relevant use in Pulmonary Arterial Hypertension (PAH). It is considered relevant for conditions marked by increased physiological stress, such as PAH, and may be part of symptomatic management for severe complications of secondary Raynaud phenomenon. Specifically, it is used for managing symptom clusters, including shortness of breath, excessive tiredness in PAH, and tissue ischemia or digital ulcers in Raynaud's. It is relevant in contexts involving heightened systemic burden.


Quick Fact: Relief for Functional Strain

Modrasil is commonly used to help with conditions presenting with disruptive symptom manifestations across the domains of sexual health and cardiopulmonary vascular management.

Regulatory References

  1. NIH MedlinePlus overview

Eligibility and Restrictions for Use

The official eligibility profile for Modrasil (sildenafil) is defined by absolute contraindications and specific patient population restrictions, as established in regulatory labeling. The medicine is generally established and permitted for use in the adult population (18 years and older).


Populations for Whom Use is Prohibited or Not Recommended

Classification Restricted Populations
Contraindicated Patients taking any form of nitrates (e.g., nitroglycerin) or guanylate cyclase (GC) stimulators (e.g., riociguat). Patients with a known hypersensitivity to sildenafil.
Use Not Recommended Individuals with a recent history of stroke or myocardial infarction (within 6 months), severe hypotension (blood pressure <90/50 mmHg), or certain hereditary degenerative retinal disorders (e.g., retinitis pigmentosa).

Age and Condition-Specific Eligibility

Age-Related Eligibility: Use for Erectile Dysfunction is not indicated for patients under 18. For Pulmonary Arterial Hypertension (PAH), use is permitted in children 1 year and older, though specific agencies have previously recommended caution, particularly against chronic high-dose use.

Special Populations: Patients with severe hepatic impairment or severe renal impairment (creatinine clearance <30 mL/min) are generally eligible, but this use is restricted and requires careful assessment due to reduced drug clearance. Use during pregnancy or lactation is typically restricted and requires specialist evaluation as safety data are limited.

What should I know about interactions with other medicines?

The interaction profile of Modrasil is defined by strict prohibitions and mandatory administration rules concerning specific co-administered substances, all documented in official government regulatory information.

Contraindicated Combinations

The most severe interaction classification is the absolute prohibition of co-administration with any form of organic nitrates, including short- and long-acting preparations, or with the soluble guanylate cyclase stimulator, Riociguat. This restriction is due to a documented risk of profound, life-threatening hypotension resulting from the potentiation of vasodilatory effects.

Pharmacokinetic and Timing Constraints

A major domain involves pharmacokinetic interactions through the primary hepatic clearance enzyme, CYP3A4. Strong inhibitors of this enzyme, such as Ritonavir or Ketoconazole, substantially increase Modrasil plasma exposure. This requires specific timing constraints: for example, the maximum single dose must not exceed 25 mg within a 48-hour period when co-administered with Ritonavir. Conversely, CYP3A inducers like Rifampin may reduce systemic exposure. Administration with a high-fat meal is documented to delay the rate of absorption.

Pharmacodynamic and Population Notes

A third interaction domain relates to additive vasodilatory effects. The co-administration of Modrasil with alpha-blockers or general antihypertensive agents may potentiate blood pressure-lowering effects, with official instructions requiring caution and low initial strength. Clearance is officially documented to be reduced in patients with severe hepatic or renal impairment, which is a critical population-specific consideration for managing systemic exposure.

Mechanism of Action

Modrasil's action is defined by a specific molecular cascade that amplifies endogenous signaling for vascular smooth muscle relaxation. The mechanism is entirely dependent on two core domains: enzyme inhibition and signal amplification.

Selective Inhibition of the PDE5 Enzyme

Modrasil initiates its effect by acting as a specific inhibitor of the Phosphodiesterase type 5 (PDE5) enzyme. This enzyme is the primary biological target responsible for the degradation of cyclic guanosine monophosphate (cGMP), a central second messenger in vascular tissue. By blocking PDE5, the drug prevents cGMP from being broken down, which sustains higher concentrations of this molecule in the cellular environment.

NO/cGMP Signal Amplification and Vasodilation

The resulting increase in cGMP levels enhances the signaling cascade initiated by endogenous Nitric Oxide (NO). This prolonged presence of cGMP activates a cascade that results in the relaxation of arterial smooth muscle cells via the reduction of intracellular calcium. The ultimate physiological consequence is vasodilation, a localized widening of the blood vessels , which represents the enhancement of localized perfusion. This conditional mechanism is active only when an initial NO signal is released.

Dosage and Administration Information

How to Use Modrasil

Modrasil (Sildenafil) is administered via two approved routes: oral (tablet or suspension) and intravenous (IV) (injection/infusion), depending on the medical condition being addressed. The medicine’s use pattern is defined by its two primary indications: Erectile Dysfunction (ED) and Pulmonary Arterial Hypertension (PAH).


Administration Scope

Feature Administration Instruction
Dosing for ED Starting dose is 50 mg (oral), adjusted from 25 mg to a maximum of 100 mg daily.
Dosing for PAH 20 mg (oral) or 10 mg IV equivalent, administered three times a day (TID).
Frequency Pattern ED: Used as needed, not to exceed once daily. PAH: Used as continuous maintenance therapy.
Timing & Food Oral dose can be taken with or without food; a high-fat meal may delay onset of action.

Procedural and Population Rules

Oral administration for ED requires administration approximately one hour before activity and is dependent on sexual stimulation for its effect. The IV route, primarily for PAH, is typically reserved for hospitalized patients temporarily unable to take the oral form, with 10 mg IV being equivalent to 20 mg oral.

For certain patient populations, dosing protocols include modifications. A lower oral starting dose of 25 mg is used for the ED indication in older adults (over 65 years) and individuals with severe hepatic or renal impairment due to altered drug clearance. If a scheduled dose for PAH is missed, the patient should take the next dose at the regularly scheduled time and not double up on the dose.

Recent Clinical Evidence

Modrasil: Overview of Clinical Evidence

This section summarizes the types of research and studies that have explored Modrasil (Sildenafil). The reported findings reflect patterns observed in groups of patients during specific study periods and should not be taken as individual predictions.


Evidence for use in Erectile Dysfunction (ED)

Research has extensively examined Modrasil in individuals with erectile dysfunction through large-scale trials monitoring short-term outcomes related to functional capacity and patient-reported outcomes describing perceived discomfort. These studies included populations with varying symptom intensity and certain coexisting conditions. Research describes the patterns observed across large groups, but the results apply only to the specific populations studied, and data for certain subgroups remain insufficient.


Evidence for use in Pulmonary Arterial Hypertension (PAH)

The evidence base for Modrasil in PAH includes populations with functional limitations. Studies utilized short-term, controlled research and open-label extension studies to explore outcomes reflecting physical activity and physiological strain. Findings described patterns associated with changes in measured outcomes. Certainty remains low in some areas, and long-term effects are not well characterized, though studies contribute to the broader evidence landscape.


Special Populations and Research Gaps

Modrasil was evaluated in select special populations, including children with PAH. Research highlighted observations that led to specific regulatory caution concerning certain dosing groups in pediatric patients. The available evidence is limited for other groups, such as those with certain comorbidities, and comparative evidence against all alternative treatments is lacking.

Key Studies & References

  1. A Randomized, Double-Blind, Placebo-Controlled Study of Sildenafil in Children With Pulmonary Arterial Hypertension (STARTS Trial Context)
  2. A meta-regression analysis of treatment effect modifiers in trials with flexible-dose oral sildenafil for erectile dysfunction in broad-spectrum populations

Frequently Asked Questions (FAQ)

Common questions about Modrasil (FAQ)

Q: Are there any common reasons Modrasil might not work for a patient?

A: Modrasil's mechanism of action is reliant on an initial physiological signal, meaning the medicine requires sexual stimulation to work; it does not directly cause an erection. Regulatory documents indicate that factors like severe liver or kidney impairment alter the body's ability to clear the drug, which is why official guidance advises dose adjustments for these populations.

Q: Is Modrasil known to cause any long-term health problems?

A: Official documentation reports rare but serious adverse reactions from post-marketing surveillance, such as prolonged erection (priapism), sudden decrease or loss of vision or hearing, and cardiovascular events. These events are often reported in temporal association with use, and patients with pre-existing risk factors may have increased susceptibility to certain reactions.

Q: Do Modrasil side effects usually get better over time?

A: Common side effects, such as headaches and flushing, are often described as mild and transient in patient information. These effects are often transient and may decrease in frequency or severity over the first few days or week of continued use, according to patient information.

Q: What are the most common interactions listed for Modrasil?

A: The most critical drug interactions are with organic nitrates (in any form) and guanylate cyclase stimulators (such as riociguat), which are both absolutely prohibited due to the risk of dangerously low blood pressure.

Q: Can Modrasil be used by women who are planning to become pregnant?

A: For the treatment of Pulmonary Arterial Hypertension (PAH), safety during pregnancy has not been definitively established. Therefore, some regulatory authorities advise that women of childbearing potential should use appropriate contraceptive measures if taking this medication.

Q: What does the term 'Modrasil contraindication' mean?

A: A contraindication is a condition or circumstance that makes the use of Modrasil potentially hazardous and therefore officially prohibited. Examples include taking organic nitrates or having a known hypersensitivity reaction to the drug or any component of the tablet.

Q: Can people who are allergic to certain inactive ingredients still take Modrasil?

A: Official documentation lists a known hypersensitivity reaction to sildenafil or any component of the tablet as a contraindication. This means the medication is contraindicated for individuals with a known hypersensitivity to the active ingredient (sildenafil) or any other component of the tablet.

Q: How long do the effects of Modrasil last after a single dose?

A: Clinical studies have shown that the effect on the erectile response was present for up to 4 hours after a single dose. However, the response may be diminished after the 2-hour mark compared to the initial effect.

Q: Does Modrasil have a 'half-life' and what does that mean in simple terms?

A: Yes, Modrasil (sildenafil) has a terminal half-life of about 4 hours. The half-life is a pharmaceutical term that refers to the time it takes for the concentration of the drug in the body to be reduced by half.

Q: What should a person do if they notice a mild side effect from Modrasil?

A: Official patient information suggests supportive measures for common, mild side effects, such as resting and staying hydrated for headaches. If symptoms worsen or persist, patients are advised to contact their healthcare provider.

Q: Can Modrasil affect mood or cause strange dreams?

A: Official documentation lists Insomnia and Anxiety as common adverse reactions (1% to 10% incidence). Other psychiatric effects, such as Abnormal Dreams, have been reported in post-marketing surveillance.

Q: Is it true that Modrasil can cause weight changes?

A: Clinical trial data for the drug's use in Pulmonary Arterial Hypertension (PAH) indicate that Increased Weight and fluid retention occurred in a small percentage of patients (1% to 10% incidence).

Q: Does Modrasil interact with common over-the-counter pain relievers?

A: Official drug interaction databases do not list a known direct interaction between sildenafil and common over-the-counter pain relievers such as acetaminophen or ibuprofen. However, all medications and supplements should be reviewed by a prescribing professional.

Q: Is it safe to take Modrasil with vitamins or natural supplements?

A: Official patient information recommends that patients discuss all substances with their healthcare provider. This includes prescription and over-the-counter medicines, vitamins, and herbal supplements, as they may influence how the body handles Modrasil.

Q: Does Modrasil pass into breast milk?

A: Yes, sildenafil and its active metabolite are excreted into human breast milk. Regulatory sources indicate that the amounts are very low, and use during breastfeeding requires a specialist's assessment of the benefits versus the potential risk.

Q: Is it okay to drink alcohol while using Modrasil?

A: Excessive alcohol consumption may increase the risk of side effects like dizziness, headache, and hypotension, as both alcohol and Modrasil can lower blood pressure. It is generally recommended to limit alcohol intake.

Q: Is Modrasil considered a controlled substance?

A: No. Modrasil (sildenafil) is not classified as a controlled substance by the US Drug Enforcement Administration (DEA) or other major government bodies, as it does not produce a euphoric effect or carry a risk of physical dependence.

Q: Can Modrasil affect one's ability to drive or operate machinery?

A: Official patient information warns that dizziness or changes in vision are documented side effects. Because of this, it may impair the ability to drive or operate machinery, and patients should be aware of this potential effect.

Q: Is Modrasil used to treat a symptom or the underlying cause of a condition?

A: The drug’s mechanism of action is described as facilitating an erection only in response to sexual stimulation, indicating its use is focused on treating the symptom of erectile dysfunction rather than the underlying cause of the condition.

Q: What is the difference between an adverse event and a side effect as listed for Modrasil?

A: Regulatory documents use these terms in the context of postmarketing surveillance. An adverse event is any reported unfavorable experience following drug use, while a side effect (or adverse reaction) is a known, unintended effect of the drug that has a reasonable probability of being caused by the drug.

Q: How is the safety of Modrasil monitored after it is released to the public?

A: Safety is continuously monitored through postmarketing surveillance and the collection of voluntary reports of suspected adverse reactions. The official drug label provides specific contact information for reporting these events to the relevant government authority.

How should Modrasil be stored and disposed of?

Official Storage and Disposal Instructions for Modrasil

Modrasil must be stored according to regulatory labeling to maintain its stability and effectiveness. The product requires storage at controlled room temperature, typically between 20 C and 25 C. It is mandatory to keep Modrasil in its original, tightly closed container to protect it from moisture and light. The label explicitly states that the product must not be frozen and should be kept out of the sight and reach of children.

For disposal, unused or expired Modrasil must not be discarded in household trash or flushed down the toilet, as prohibited by environmental guidelines. Patients should return the medicine to a drug take-back program or an authorized pharmacy collection point for safe and proper disposal.

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

Available in countries:

Equivalent of Modrasil found in:

A-Z Index: