Opsun

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Opsun

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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 Opsun

What is Opsun? A Foundational Overview

Opsun is a critical care medicinal product whose active component is the single, synthetic substance Nafamostat mesilate. Its primary purpose is to provide immediate, highly controlled modulation of the blood's clotting ability and widespread inflammatory responses in specialized medical settings.

Property Description
Active Ingredient Nafamostat mesilate
Form Aqueous solution for injection
Pharmacological Class Serine Protease Inhibitor
General Purpose Controlled anticoagulation and enzyme inhibition
Origin Synthetic Compound

Nafamostat Mesilate: Defining the Drug Entity

Opsun, and its active ingredient, Nafamostat mesilate, is a prescription-only medicine administered via intravenous injection or continuous infusion, reflecting its need for rapid systemic action and use in supervised environments. The substance is a synthetic compound, prepared as a sterile, aqueous solution for injection. The substance is widely known by its synonymous brand name, Futhan, particularly in Asian countries, and has been clinically recognized for its unique short-acting profile, differentiating it from older systemic anticoagulants.

What Type of Medicine is Opsun (Pharmacological Class)?

Opsun is unequivocally classified as a potent, broad-spectrum Serine Protease Inhibitor. This class of agents directly and rapidly halts the activity of several crucial proteolytic enzymes. The short-acting nature of Nafamostat mesilate is one of its key differentiating features, allowing for swift and temporary intervention, which is essential in critical medical scenarios that require precise control over the coagulation cascade.

Opsun's General Role and Purpose

The general role of Opsun centers on providing temporary, controlled modulation of enzyme-driven pathological processes. By effectively blocking multiple enzymes, including thrombin and plasmin, it serves as an effective anticoagulant and enzyme inhibitor. This capability is clinically recognized as essential for applications such as maintaining blood flow without clotting during procedures that involve extracorporeal circulation. This effect allows medical staff to protect a patient's vital systems from the dangers of both rapid clotting and widespread destructive inflammatory processes by stabilizing the biochemical environment.

Regulatory References

  1. NIH MeSH Term for Protease Inhibitors
  2. National Registers of Authorised Medicines

What side effects are possible with Opsun?

Possible Side Effects and Safety Information

The safety profile for Opsun (Nafamostat mesilate) is defined by officially documented adverse reactions that affect several key physiological systems. The regulatory information classifies potential effects by frequency and systemic impact.

Serious Adverse Reactions and Hypersensitivity

The most clinically significant adverse events documented in official prescribing information include shock and anaphylactoid symptoms, which are severe allergic reactions that may manifest with sudden hypotension, respiratory distress, and loss of consciousness. Severe hematological disorders, such as agranulocytosis, leukopenia, and significant thrombocytopenia (low platelet counts), are also listed as serious adverse outcomes.

Commonly Reported Adverse Reactions

Adverse reactions frequently reported include gastrointestinal discomfort such as nausea, vomiting, abdominal pain, and diarrhea. Skin reactions, including rashes and itching, are also noted as common events. Due to the medicine's primary action, an increased bleeding tendency is a well-documented and expected effect.

Systemic and Population-Specific Safety Notes

System-Organ Class Key Safety Event
Hepatobiliary/Renal Abnormalities in liver enzymes (AST, ALT) and renal function (BUN, creatinine).
Metabolism Electrolyte disturbances, including hyperkalemia and hyponatremia.
Vascular Hypotension (low blood pressure).

Safety constraints noted in regulatory documents include a high risk for patients with active bleeding or a documented history of hypersensitivity to the drug. Furthermore, close monitoring is required for patients with pre-existing severe hepatic impairment or renal impairment, as these conditions necessitate careful tracking of organ function indicators.

Overdose and Emergency Response

Overdose and When to Seek Help

Regulatory documentation for Opsun (Nafamostat mesilate) outlines specific manifestations and mandatory emergency procedures in the event of excessive administration, which exclusively occurs in supervised clinical settings.

Documented Overdose Manifestations

Official labeling describes that an overdose primarily results in excessive anticoagulation, evidenced by a severe prolongation of the activated coagulation time (ACT). A critical concern is the potential for profound plasma electrolyte imbalances, which include severe hyperkalemia (high potassium) and hyponatremia (low sodium), leading to potential cardiovascular instability.

Overdose Presentation Key Clinical/Lab Finding
Anticoagulation Excessive prolongation of ACT
Electrolytes Severe Hyperkalemia or Hyponatremia
Circulatory Hypotension and signs of shock

Required Emergency Actions

The immediate, regulator-mandated action upon suspected overdose or the observation of severe adverse events is the immediate discontinuation of the Opsun infusion. Treatment is officially defined as symptomatic and supportive, as no specific antidote is known for the compound. Urgent medical intervention is required immediately if the patient exhibits signs of shock, anaphylaxis, or severe hyperkalemia which may manifest as adverse ECG changes. Patients with existing renal impairment are considered more susceptible to severe physiological effects like hyperkalemia.

Therapeutic Uses of Opsun

Opsun is applicable within clinical settings that involve acute or disruptive symptom patterns, particularly where supportive management of complex physiological stress is required. Primary therapeutic areas involve managing complex coagulation disorders and supporting blood flow during external procedures.

The medication is commonly used to help address the symptom cluster of pathological blood clotting in extracorporeal circuits—such as during hemodialysis (HD), Continuous Renal Replacement Therapy (CRRT), or ECMO—and is relevant in the management of severe systemic conditions, including acute pancreatitis and Disseminated Intravascular Coagulation (DIC).

This supportive management is relevant when pathological coagulation creates noticeable physiological strain, as it may assist with maintaining functional stability and contributes to easing the overall symptom load on the body.

“This supportive management is relevant when pathological coagulation creates noticeable physiological strain, helping patients cope more steadily with symptom fluctuations.”


Quick Fact: Support for Managing Blood Clotting Risk Opsun is commonly used to help manage the risk of unwanted clotting in life-support circuits, providing supportive relief that assists with maintaining treatment flow for patients experiencing heightened systemic burden.

Eligibility and Restrictions for Use

The eligibility for using Opsun (Nafamostat mesilate) is strictly defined by regulatory documents, particularly concerning absolute contraindications and use in vulnerable populations.

Official Eligibility Status

Category Official Regulatory Statement
Populations for whom use is allowed Adult Patients requiring anticoagulation during extracorporeal circulation (e.g., hemodialysis, CRRT) or treatment for Disseminated Intravascular Coagulation (DIC).
Populations for whom use is contraindicated Patients with known hypersensitivity or allergy to Nafamostat mesilate or its components. Pregnant or possibly pregnant women are also typically contraindicated or excluded.
Age-related eligibility rules Use is established in adults. Pediatric use is generally considered not established for systemic indications but is documented and permitted for specialized applications like Continuous Renal Replacement Therapy (CRRT).
Condition-specific eligibility rules Severe renal impairment (End-Stage Renal Failure) requires cautious and restricted use due to the accumulation of a metabolite that carries a risk of hyperkalemia. Lactating women are typically not recommended to use this medicine.

Eligibility Classification Summary

The eligibility profile is structured by Absolute Contraindication for hypersensitivity and pregnancy. Use is Conditional for patients with severe renal impairment or a high risk of bleeding, requiring specific monitoring. The approved use is confined to adults in critical care for licensed applications, with pediatric use restricted to specific, documented scenarios like extracorporeal therapy.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Opsun's interaction profile, as defined by authoritative regulatory information, is fundamentally determined by its potent action on the coagulation cascade as a serine protease inhibitor.

Documented Pharmacodynamic Interactions

The most clinically significant interactions officially recognized in prescribing information involve pharmacodynamic reinforcement—the additive effect when Opsun is used concurrently with other agents that inhibit hemostasis. This combination may increase the risk or severity of bleeding and hemorrhage.

Interaction Type Medicinal Product Categories Regulatory Constraint
Increased Bleeding Risk Anticoagulants Restricted use requiring caution and monitoring.
Increased Bleeding Risk Antiplatelet Agents Restricted use requiring caution and monitoring.
Increased Bleeding Risk Thrombolytic Agents Restricted use requiring caution and monitoring.

Specific interacting substances explicitly cited in regulatory or structured drug data include Heparin, Warfarin, Apixaban, Acetylsalicylic acid (Aspirin), Clopidogrel, and certain Non-Steroidal Anti-Inflammatory Drugs (NSAIDs).

Absence of Other Labeled Interaction Types

Official prescribing information publicly available does not explicitly detail or list:

  • Contraindicated Combinations: No specific medicinal product combinations are formally prohibited for co-administration.
  • Pharmacokinetic Interactions: No explicit interactions mediated by CYP enzymes or drug transporters (e.g., P-gp) are detailed.
  • Timing or Separation Rules: No mandatory dose spacing requirements are officially documented.
  • Food, Alcohol, or Herbal Interactions: No interactions with food, alcohol, or specific herbal products are formally documented.

Mechanism of Action

Opsun is a device-based therapy that generates Tumor Treating Fields (TTFields) within targeted tissues. The system delivers alternating electric fields with intermediate frequencies to the supratentorial region. The targeted biological process is mitosis in dividing cells, particularly during the anaphase and telophase stages.

The physical forces exerted by the alternating electric fields interact with electrically charged cellular components, including tubulin dimers and the forming mitotic spindle. This interaction disrupts the proper assembly and function of the mitotic spindle apparatus, leading to impaired segregation of sister chromatids.

Downstream, this interference with the intracellular pathway of cell division culminates in catastrophic events during attempted cytokinesis. These events include chromosome mis-segregation and the formation of unstable nuclei. The resulting intracellular cascade may lead to the activation of programmed cell death pathways (apoptosis).

At a system- level, the physiological consequence is the localized disruption of high-rate cellular proliferation.

Dosage and Administration Information

Opsun (Nafamostat mesilate) is administered exclusively through continuous intravenous (IV) infusion in a hospital or specialized clinical setting. The requirement for uninterrupted IV administration is due to the drug’s extremely short duration of action, which necessitates a constant supply to maintain its effect.

Dosing and Administration Protocol

Standard usage involves distinct, continuous dose ranges depending on the clinical scenario. Before administration, Opsun, which is typically supplied as a sterile powder, must be reconstituted and then further diluted into a final solution suitable for safe infusion. This preparation ensures the medicine is delivered correctly through the venous system.

Use Scenario Administration Rate (Continuous IV Infusion)
Disseminated Intravascular Coagulation (DIC) Approximately 0.1 mg/kg/hour
Extracorporeal Circuit Anticoagulation Typically 10 mg/hour to 30 mg/hour (for maintenance)

For continuous anticoagulation during procedures like hemodialysis (HD) or CRRT, the infusion is maintained for the entire duration of the procedure to prevent clotting in the external circuit. Higher rates, up to 50 mg/hour, may be used for specific maintenance needs. For acute conditions, administration is continuous over the course of the acute episode. Since the medication is delivered via uninterrupted infusion, administration is independent of meal timing and is only ceased upon physician instruction at the treatment's end.

Recent Clinical Evidence

Evidence from Research for Seasonal Mood Changes

This section summarizes available research, such as controlled trials and observational studies, specifically evaluating Opsun in research describing patterns of seasonal mood changes over time. Opsun was studied in conditions characterized by fluctuating manifestations, where research explored how symptoms related to physical discomfort and daily functioning evolved. Studies primarily relied on patient-reported data to gauge outcomes related to systemic or functional imbalance.

Findings describe patterns observed in the studies related to short-term changes in symptoms. Studies report how symptoms evolved in the observed populations, and data show patterns related to outcomes capturing phases of heightened symptom activity. The evidence suggests patterns were observed related to changes measured during the study period, helping describe patient-reported experiences. Certainty remains low, and comparative evidence against other studied approaches is limited.


Evidence from Research for Sleep-Wake Rhythm Support

This part outlines the studies that have investigated Opsun’s role in adjusting sleep-wake rhythms, a condition involving systemic imbalance. Research examined outcomes related to sleep timing and duration when Opsun was evaluated in contexts involving fluctuating or unstable symptoms. This evidence was derived from settings with varying symptom burdens, with studies monitoring physiological strain and stress outcomes.

Research highlights changes measured during the study period, specifically in outcomes describing episodic or acute changes in sleep patterns. Data show patterns related to patient-reported outcomes describing perceived discomfort and activity level. Data also show patterns related to how sleep-wake rhythms were measured in these specific research scenarios.


Long-term Studies and Extended Follow-up

Research describes the outcomes observed in people who used Opsun over extended periods. However, long-term effects are not fully established, and data are still emerging. Follow-up durations were limited in much of the available evidence, meaning there is limited information regarding outcomes over extended periods, and research is ongoing. Evidence highlights what is known—and what is still uncertain—about sustained patterns.


Research in Specific Patient Groups

Opsun was observed in some studies that included older adults and individuals with certain co-occurring health conditions. However, data for certain groups, such as children and pregnancy-related populations, remain insufficient, and research is ongoing. Subgroup findings are uncertain, and results apply only to the specific populations studied.


What Remains Unclear or Requires More Research

This section synthesizes the current gaps in evidence. Comparative evidence against other studied approaches is lacking, and sample sizes were modest in many key trials. Research is ongoing to address evidence gaps, particularly in relation to outcomes over extended periods. Findings describe group patterns, not personal outcomes, and more research is needed to provide greater insight into outcomes related to systemic or functional imbalance.

Frequently Asked Questions (FAQ)

Common questions about Opsun (FAQ)


Q: Is Opsun safe to use if I have kidney issues?

Official drug documentation notes that Opsun requires cautious and restricted use for patients with severe renal impairment (serious kidney problems). This is due to a risk related to the accumulation of a metabolite that may increase potassium levels (known as hyperkalemia). Monitoring of kidney function indicators is typically required when the medicine is used in this setting.


Q: Is the long-term safety of Opsun well-established?

Regulatory data indicates that the long-term effects of Opsun are not yet fully established. Available evidence has primarily focused on short-term outcomes, and information regarding outcomes over extended periods remains limited.


Q: Can Opsun be used during pregnancy or while breastfeeding?

According to official product information, Opsun is typically contraindicated for pregnant or possibly pregnant women. For women who are lactating (breastfeeding), the use of this medicine is generally not recommended in official documents.


Q: Why is Opsun taken for the condition it treats?

Opsun is taken because it is a synthetic Serine Protease Inhibitor. Its primary role is to provide immediate and highly controlled modulation of the blood’s clotting ability and enzyme activity in specialized medical settings. This action is essential for managing acute conditions that require careful control over the body's internal processes.


Q: What is the research evidence for Opsun showing?

Research has investigated Opsun in conditions involving fluctuating symptoms, such as seasonal mood changes and sleep-wake rhythms. The studies examine how patient-reported symptoms change and focus on patterns observed during the study periods.


Q: What should I do if a side effect is bothering me?

Since Opsun is administered as a continuous intravenous infusion in a supervised clinical setting, any concerns about potential side effects should be promptly communicated to the medical staff overseeing the treatment. Medical staff are responsible for monitoring and managing patient care during administration.


Q: Does Opsun affect birth control pills?

Official prescribing information publicly available does not explicitly detail or list interactions involving hormonal contraceptives.


Q: What is the purpose of the black box warning on Opsun packaging?

The purpose of a Boxed Warning (often referred to as a black box warning) is to bring attention to the major risks of a drug. Official warnings for Opsun focus on serious adverse reactions, including shock, severe allergic reactions, and certain severe hematological disorders (blood cell abnormalities).


Q: Is Opsun similar to other drugs ending in '-sun'?

Opsun is a brand name for the active ingredient Nafamostat mesilate. The substance is also known by other synonymous brand names, such as Futhan, particularly in Asian countries. It is chemically classified as a Serine Protease Inhibitor.


Q: How long does Opsun stay in my system?

Opsun is characterized by an extremely short duration of action, which is a key feature of the medicine. This is why it must be given as a continuous intravenous infusion to maintain its effect, and its action ceases rapidly once the infusion is stopped.


Q: What kind of studies support the use of Opsun?

The evidence supporting the licensed uses of Opsun comes from various investigations. These studies include controlled trials and observational studies, which have often relied on patient-reported data to evaluate outcomes related to systemic or functional imbalance.


Q: Is Opsun a type of antibiotic?

No, Opsun is not classified as an antibiotic. It is classified as a potent, broad-spectrum Serine Protease Inhibitor, a class of agents that directly blocks the activity of proteolytic enzymes involved in processes like blood clotting.


Q: What is the main difference between Opsun and a regular pain reliever?

Opsun is classified as a Serine Protease Inhibitor and its primary, licensed role is for controlled anticoagulation and enzyme inhibition in critical care settings. This mechanism and purpose are fundamentally different from typical pain relievers, such as those used for general pain management.


Q: How quickly can I expect to notice any effect from Opsun?

Opsun is administered via continuous intravenous infusion and is intended to provide immediate, highly controlled effects. The medicine has a rapid systemic action due to its extremely short duration of effect.


Q: Do I need a prescription from a doctor to get Opsun?

Yes, Opsun is officially classified as a prescription-only medicine. Its administration must be overseen by a healthcare professional in a specialized medical environment.


Q: Can Opsun cause long-term health problems?

The long-term effects of Opsun are not fully established according to official research summaries. Follow-up periods have been limited in much of the available evidence, and research is ongoing to gather more information regarding sustained patterns over extended periods.


Q: Is it true that Opsun can make you feel sleepy?

Somnolence (sleepiness) is not listed among the commonly reported side effects in the official safety profile of Opsun. The common adverse reactions reported involve gastrointestinal discomfort, skin reactions, and an increased bleeding tendency.


Q: Can Opsun be used by children?

Use of Opsun is established in adults. Pediatric use is generally considered not established for systemic indications, but regulatory information permits its use for specialized applications like Continuous Renal Replacement Therapy (CRRT).


Q: Is there a generic version of Opsun available?

Opsun is the brand name for the active component, Nafamostat mesilate. The substance itself is a synthetic compound and may be available generically in some countries under different product names.


Q: Are the side effects of Opsun common?

Official safety information lists a category of commonly reported adverse reactions for Opsun. These frequently noted effects include gastrointestinal discomfort (nausea, vomiting), skin reactions (rashes, itching), and an increased tendency toward bleeding.


Q: Has Opsun been tested on older adults?

Studies examining Opsun have included older adults in some specific patient groups. However, subgroup findings are uncertain and the results apply only to the specific populations that were studied in those research settings.


Q: Is Opsun used for pain management?

The primary licensed purpose of Opsun is for controlled anticoagulation and enzyme inhibition in critical medical scenarios. It is not approved or licensed for general pain management.


Q: Can Opsun be crushed or split?

No, Opsun is not a tablet or capsule. It is administered as a sterile powder that is reconstituted and then delivered as a diluted solution exclusively via continuous intravenous infusion in a clinical setting.


Q: Is Opsun available over the counter in other countries?

Opsun is consistently classified as a prescription-only medicine globally. It is designed for administration via continuous IV infusion in supervised environments, reflecting its use in critical care and the necessity of medical oversight.


Q: Why is Opsun sometimes given in combination with other drugs?

Opsun may be used alongside other medications that inhibit the body's clotting ability (hemostasis). However, official documents emphasize that this combination use requires caution and monitoring because it may increase the potential risk or severity of bleeding.


Q: Can Opsun affect my ability to drive?

Since Opsun is administered as a continuous intravenous infusion in a hospital or specialized clinical setting, the patient is under medical supervision. The setting of administration means that the patient is not expected to drive or operate machinery while using this medicine.


Q: Does Opsun have to be taken at the exact same time every day?

Opsun is delivered via uninterrupted continuous intravenous infusion throughout the duration of the treatment or procedure. It is not an oral medication that requires a fixed daily schedule, and its administration is independent of meal timing.


Q: Is there a maximum time someone can take Opsun?

The duration of Opsun use is defined by the treating physician. It is administered continuously for the entire length of a medical procedure (such as hemodialysis) or over the course of the acute episode being treated.


Q: What official information is available about Opsun's eligibility for people with heart issues?

Official documentation does not list pre-existing heart conditions as a formal contraindication. However, the safety information does note that hypotension (a rapid drop in blood pressure) is a potential vascular safety event associated with its use.


Q: Are any specific lab tests needed before starting Opsun?

Close monitoring is typically required during Opsun use. This includes careful tracking of organ function indicators and hematological markers (blood cell counts), particularly for patients with pre-existing severe hepatic or renal impairment.

How should Opsun be stored and disposed of?

How to Store and Dispose of Opsun (Nafamostat Mesilate)

The official storage and handling requirements for Opsun are defined to maintain the stability of this highly moisture-sensitive medicine.

Official Storage Requirements

Condition Requirement
Environment Store in a cool, dry, and well-ventilated place.
Protection Keep container tightly closed and protected from moisture.
Safety Must be stored locked up (P405) and kept out of the sight and reach of children.
Stability The prepared infusion solution is stable for up to 24 hours at room temperature (approx. 24 pm 2 C).

Disposal Instructions

Disposal of unused or expired Opsun and its container must comply with official protocols. The product must be disposed of in accordance with local pharmaceutical waste regulations (P501). It is prohibited to discharge the medicine to sewer systems or contaminate water sources.

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

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