Metadon Hemofarm

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Metadon Hemofarm

Method of action: Analgesic, Opioid

Treatment option: Pain, Drug Addiction

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 Metadon Hemofarm

Quick Facts

Property Description
Active ingredient Methadone hydrochloride
Form Oral solution, Tablets, Solution for injection
Pharmacological class Opioid analgesic, Synthetic opioid
General purpose Severe chronic pain management; Opioid substitution therapy (OST)
Origin Synthetic (chemically manufactured)

1. Defining Metadon Hemofarm: A Synthetic Opioid Analgesic

Metadon Hemofarm is a prescription-only drug classified as a synthetic opioid analgesic belonging to the narcotic pharmacological class. The core component is Methadone hydrochloride, which functions as a powerful mu-opioid receptor agonist. Because it is manufactured chemically rather than naturally derived, it is correctly identified as a synthetic substance. This specific brand is produced by Hemofarm A.D. in Serbia. The substance is included on the World Health Organization's Model List of Essential Medicines, recognizing its global therapeutic utility.

2. Forms and Core Composition

The sole active ingredient in Metadon Hemofarm is Methadone hydrochloride, which is supplied in multiple dosage forms for sustained action. The medication is not a combination product. It is produced as an oral solution and in tablet form, as well as a solution for injection, allowing for administration via the oral and parenteral routes. The availability of the oral liquid is a key feature, as this formulation is often preferred in maintenance programs.

3. General Therapeutic Role and Purpose

The general purpose of Metadon Hemofarm is to achieve sustained pain relief and provide pharmacological stability for treatment programs. Methadone is clinically recognized for its long duration of action and half-life. This long-acting property provides patients with stable relief and reduces the intensity of withdrawal symptoms over an extended duration. As an opioid agonist, it effectively manages severe, persistent chronic pain and is the established mechanism underlying its use in Opioid Substitution Therapy (OST).

Regulatory References

  1. WHO Essential Medicines List (Methadone)
  2. Methadone - NIH StatPearls

What side effects are possible with Metadon Hemofarm?

Possible side effects and safety information

Metadon Hemofarm (methadone hydrochloride) is associated with a range of officially documented adverse reactions, classified by frequency and affected organ system in regulatory documents such as the FDA prescribing information and the EMA Summary of Product Characteristics (SmPC).

Serious Adverse Reactions and Safety Constraints

The most significant, life-threatening risks documented in regulatory warnings are Life-Threatening Respiratory Depression and severe QT Prolongation and Torsade de pointes, a serious cardiac arrhythmia. The risk of respiratory depression is notably highest during the initiation of treatment or following a dosage increase. Other high-level safety constraints include the risk of Neonatal Opioid Withdrawal Syndrome (NOWS) if used during pregnancy, and the potential for Profound Sedation, Coma, and Death if co-administered with Central Nervous System (CNS) depressants.

Commonly Documented Adverse Reactions

The safety profile includes adverse reactions that are classified as very common or common in regulatory listings. Nausea and vomiting are classified as very common. Effects categorized as common involve several body systems, including sedation, dizziness, and lightheadedness (Nervous System Disorders), and constipation and sweating, which are documented to often persist during long-term chronic use.

Systemic and Population-Specific Safety

Adverse effects are also categorized by System-Organ Class (SOC), including Endocrine Disorders (e.g., hypogonadism, adrenal insufficiency) and Gastrointestinal Disorders (e.g., xerostomia). Safety considerations are also defined for vulnerable groups; use in patients with severe hepatic or renal impairment may require particular caution or avoidance, as stated in official labeling.

Overdose and Emergency Response

Overdose and When to Seek Help

Overdose with Metadon Hemofarm is a medical emergency documented in regulatory labeling with specific, life-threatening manifestations.

Documented Manifestations and Severe Outcomes

Overdose primarily presents as profound central nervous system (CNS) depression, characterized by excessive sleepiness, confusion, coma, and pinpoint pupils (miosis). The most severe complication is life-threatening respiratory depression, which can lead to fatal outcomes. Official documents also warn of serious cardiac toxicity, including QT interval prolongation and the risk of the severe arrhythmia Torsades de pointes. Accidental ingestion by a child is explicitly stated to result in fatal overdose. Furthermore, elderly or debilitated patients are noted as being at an increased risk for severe respiratory compromise.

Emergency Response and Required Monitoring

Any suspected overdose requires immediate medical attention. Regulators mandate that emergency services be contacted right away. The specific opioid antagonist Naloxone is available to reverse the drug's effects. Management is supportive, including assistance with respiration. Due to the long half-life of Methadone hydrochloride, extended hospital monitoring is a required procedural step to track for potential recurrence of respiratory depression, even after initial symptom reversal.

Official Overdose Statements

  • Life-threatening respiratory depression and coma are officially documented as severe consequences of overdose.
  • Overdose carries a specific, officially documented risk of QT interval prolongation and Torsades de pointes.
  • Regulators mandate that the antidote Naloxone be available, and that immediate medical attention is sought for suspected overdose.

Therapeutic Uses of Metadon Hemofarm

Metadon Hemofarm is commonly used across two primary therapeutic domains.

Core Support for Opioid Use Disorder (OUD)

This domain is applicable within clinical settings that involve acute or disruptive symptom patterns related to opioid dependence. It is relevant for managing the symptom clusters of opioid withdrawal symptoms and persistent craving, which are symptoms that interfere with daily functioning. This application provides supportive relief that generally assists with maintaining functional stability.

“This medication may assist with easing challenging physical and psychological symptoms associated with dependence, supporting patients during difficult episodes.”

It is relevant in contexts involving heightened systemic burden to support patients during difficult episodes by easing distress. The primary indications covered are detoxification treatment and maintenance therapy for opioid addiction.

Management of Severe Chronic Pain Syndromes

The medication is commonly applied in conditions where patients experience severe, persistent pain that is associated with continuous symptomatic support. It is relevant in conditions where symptoms may intensify temporarily, such as certain cancer or neuropathic pain states, when additional management of discomfort is required. This use offers symptomatic relief that helps patients cope more steadily. This is used for managing moderate-to-severe pain in situations where initial treatments have not adequately eased the symptom burden. It contributes to improved day-to-day comfort and assists with maintaining functional stability when symptoms may intensify temporarily or fluctuate.


Quick Fact: Relief for Chronic Pain and Opioid Symptoms

Aspect Description
Primary Indication Opioid Use Disorder (OST) and Severe Chronic Pain
Symptom Goal Suppression of withdrawal symptoms and persistent craving
Therapeutic Benefit Supports functional stability and continuous comfort

Regulatory References

  1. National Institute on Drug Abuse (NIDA) at the NIH

Eligibility and Restrictions for Use

Eligibility Profile: Who Can and Cannot Use Metadon Hemofarm

Eligibility to use Metadon Hemofarm is strictly defined by official regulatory criteria, which establish absolute prohibitions and conditional use requirements for specific patient populations. This information is derived from government-approved labeling.

Absolute Contraindications

The medicine is prohibited for use in patients with the following conditions, as they are deemed absolute contraindications:

Condition or Group Regulatory Rule
Significant respiratory depression Must not be used
Acute or severe bronchial asthma Must not be used
Known or suspected paralytic ileus Must not be used
Known hypersensitivity to methadone Must not be used

Restricted and Conditional Use

Use is restricted or requires special consideration in several patient groups, necessitating caution and monitoring:

  • Cardiac Risks: Close cardiac monitoring is mandated for patients with risk factors for QT interval prolongation or other cardiac conduction abnormalities.
  • Organ Impairment: Patients with renal impairment and non-severe hepatic impairment require cautious use due to the risk of drug accumulation. Severe hepatic impairment is strictly contraindicated in certain regulatory jurisdictions.
  • Age Groups: Use is not recommended in the pediatric population (under 18 years) due to insufficient established clinical data. Older adults require careful use due to potential accumulation.
  • Pregnancy: Prolonged use during pregnancy is associated with the expected risk of Neonatal Opioid Withdrawal Syndrome (NOWS), an outcome documented in official labeling.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Official regulatory information for Methadone hydrochloride establishes specific constraints regarding co-administration with other substances based on pharmacokinetic and pharmacodynamic interactions.

Contraindicated and High-Risk Combinations

Methadone is formally contraindicated with Monoamine Oxidase Inhibitors (MAOIs). Use is prohibited within 14 days of discontinuing an MAOI. Co-administration with Mixed Opioid Agonist/Antagonists (e.g., Naltrexone, Buprenorphine) is restricted, as these can precipitate acute opioid withdrawal symptoms in physically dependent patients.

Interaction Type Interacting Categories
Pharmacodynamic CNS Depressants (e.g., Benzodiazepines, Alcohol, Sedatives), Serotonergic Drugs, QT-Interval Prolonging Agents
Pharmacokinetic CYP Enzyme Inducers (e.g., Rifampin, Phenytoin), CYP Enzyme Inhibitors (e.g., Ketoconazole, Macrolide Antibiotics)

The pharmacokinetic interactions primarily involve the cytochrome P450 (CYP) enzyme system, specifically CYP3A4, CYP2B6, and CYP2C19. CYP Inducers accelerate methadone metabolism, potentially reducing plasma levels and causing decreased effects. Conversely, CYP Inhibitors reduce methadone clearance, leading to increased exposure and toxicity risk.

Pharmacodynamic interactions carry the risk of additive effects, notably profound sedation and respiratory depression when combined with Alcohol or other CNS depressants. Additive cardiotoxicity is a risk when combined with QT-prolonging agents. Regulatory notes indicate an increased risk of respiratory depression in elderly or debilitated patients during co-administration with CNS depressants.

Mechanism of Action

Activation of Central Inhibitory Pathways

This drug primarily functions as a full agonist at the mu-opioid receptor (mu-OR) in the central nervous system. Activation of this G-protein coupled receptor initiates inhibitory signaling cascades that effectively modulate the transmission of specific signals within nerve pathways. The mu-OR activation results in a specific change in the output of inhibitory neural pathways, leading to the modulation of the central nervous system's response to specific afferent signals.


Modulation of Nerve Cell Excitability

A secondary mechanism involves the drug acting as an antagonist at the NMDA receptor. By blocking this receptor, which is part of the glutamatergic system, the drug limits the overall firing rate of nerve cells. This modulation assists in limiting neuronal hyperexcitability and alters sensitivity patterns.


Influence on Neurotransmitter Recycling

The drug contributes to its effect profile by mildly inhibiting the reabsorption (reuptake) of monoamine neurotransmitters, specifically serotonin and norepinephrine. This action increases the concentration of these molecules at the synapse, engaging descending regulatory pathways and altering the state of signaling within targeted systems.

Dosage and Administration Information

Metadon Hemofarm (methadone hydrochloride) must be used strictly according to official guidelines, which detail the administration method, dosing schedule, and required supervision. Because of the long half-life and risk of drug accumulation, precise titration and adherence to the schedule are mandated.

Official Routes and Forms

Administration Type Approved Route(s) Forms Preparation Requirement
Oral Oral intake Tablets, Oral Solution, Dispersible Tablets 40 mg dispersible tablets must be mixed in approx. 120 mL of liquid and taken immediately.
Parenteral Intravenous (IV), Intramuscular (IM), Subcutaneous (SC) Solution for Injection Used only for pain management, not for routine opioid substitution therapy.

Standard Dosing and Schedule

For Opioid Substitution Therapy (OST), the starting dose is typically 20 mg to 30 mg as a single daily dose, administered under supervision within a certified treatment program. The usual dose for maintenance is commonly in the range of 80 mg to 120 mg per day.

For Severe Chronic Pain in opioid-naïve patients, the initial dose is generally 2.5 mg taken every 8 to 12 hours. Dose increases for chronic pain must be performed cautiously and no more frequently than every 5 to 7 days to allow plasma levels to stabilize due to the drug's prolonged action.

Population-Specific Adjustments

Official labels recommend extreme caution when dosing older adults and patients with hepatic or renal impairment, often necessitating the use of lower initial doses and slower titration rates. Methadone is generally not recommended for the pediatric population.

Recent Clinical Evidence

Research Evidence / Overview of Studies

Mechanism of Action

Research has explored the hypothesis that the drug influences the activity of Substance P. The component's affinity to the NK1 receptor was evaluated in preclinical models. This research explored the biological basis for the component.


Clinical Efficacy Studies

Combination Therapy

Studies have investigated whether the combination is associated with changes in mobility, and examined its potential association with pain and stiffness.

  • Study A (Phase III RCT): This study evaluated 500 participants over six months. The primary endpoint was defined as a change in the Modified Health Assessment Questionnaire (MHAQ) score. Secondary endpoints included measures of joint swelling and tenderness.
  • Study B (Observational Cohort): This long-term study followed participants for three years. The research examined the long-term patterns of use and participant-reported outcomes. The findings reported a change in inflammation over the observed period in a subset of participants.

Monotherapy Trials

Monotherapy trials were conducted to isolate the effects of the active component alone. These trials focused on participants with mild-to-moderate conditions.

  • Study C (Dose-Ranging Trial): This trial investigated the tolerability and safety profile across three different dosages. The results were used to inform the selection of the trial dose for subsequent studies.
  • Study D (Single-Blind Crossover): This study evaluated the subjective experience of participants on the drug versus a placebo over a four-week period. The primary focus was on measuring changes in morning stiffness.

Pharmacokinetics and Administration

Studies have evaluated whether taking the drug with food influences the observed effect. Additionally, research examined the time to peak plasma concentration, which was observed to be between 2 and 4 hours after oral intake.


Comparative Research

Studies have compared the formulation with previous treatments regarding study measures related to flare-ups. This comparative research primarily used patient-reported outcomes scales to gather data. Further, an in vitro study evaluated the relative receptor occupancy compared to other drugs in the same class.

Frequently Asked Questions (FAQ)

Common questions about Metadon Hemofarm (FAQ)


Q: Is Metadon Hemofarm the same as regular methadone?

Metadon Hemofarm is a brand name formulation, while the active ingredient is methadone hydrochloride. Official sources indicate this same generic drug is available under other brand names, such as Dolophine and Methadose, as well as in generic forms.


Q: What does 'opioid agonist' mean in simple terms?

The medication is classified as an opioid agonist. This means it works by changing how the brain and nervous system perceive signals, providing its effect in managing pain and supporting opioid substitution therapy (OST).


Q: Can Metadon Hemofarm be taken long-term?

Regulatory guidelines for opioid use disorder (OUD) confirm that methadone is used for long-term maintenance treatment. The length of treatment varies among individuals, but for some, long-term maintenance is required and can exceed one year.


Q: What is the difference between methadone and buprenorphine?

Regulatory texts describe methadone as a full opioid agonist, meaning it fully activates the opioid receptors. In contrast, buprenorphine is described as a mixed agonist/antagonist, which acts differently on these receptors.


Q: How long do the effects of one dose typically last?

For pain relief, the effect of a single dose generally lasts 4 to 8 hours. However, its long half-life allows it to provide stable drug levels, which allows for the established use of once-daily dosing in OST protocols.


Q: What are the signs of too much Metadon Hemofarm?

Official product information lists signs of excessive exposure or overdose, including severe and life-threatening respiratory depression (severely slowed breathing) and extreme drowsiness. Other signs can include cold, clammy skin and confusion, which may lead to coma.


Q: Is Metadon Hemofarm addictive?

Methadone is classified by regulatory bodies as a Schedule II controlled substance. This classification exists because the drug has a recognized high potential for abuse. The abuse of the drug may lead to the development of severe psychological or physical dependence.


Q: How long does Metadon Hemofarm stay in the body?

According to official labeling, the elimination half-life of methadone is highly variable, ranging from 8 to 59 hours. This long half-life is the reason the drug and its effects persist in the body for an extended time.


Q: Does it matter what time of day I take Metadon Hemofarm?

When the medication is taken for opioid addiction, official guidance highlights the importance of maintaining a consistent daily schedule. If the medication is taken for pain, the fixed dosing schedule requires doses to be taken at the intervals prescribed by the physician.


Q: Why is Metadon Hemofarm classified as a controlled substance?

The drug is classified as a Schedule II controlled substance by government agencies. This classification is due to its high potential for abuse and the risk of severe dependence, requiring strict regulatory control over its dispensing.


Q: Is it normal to feel a little dizzy when first starting?

Dizziness and lightheadedness are listed in official documents as common side effects. The risk of serious side effects, such as breathing difficulty, is generally documented as being highest during the initiation of treatment or following a dosage increase.


Q: What are the specific interactions with grapefruit?

Official regulatory warnings exist regarding the consumption of grapefruit or grapefruit juice. This is because these products may increase the amount of methadone that enters the bloodstream, potentially leading to an increased risk of side effects.


Q: Are there different brand names for the same active ingredient?

Yes. The active ingredient, methadone hydrochloride, is available under the brand name Metadon Hemofarm. It is also sold under other brand names, such as Dolophine and Methadose, as confirmed by official drug information sources.


Q: Why is QTc prolongation a concern with this medicine?

Methadone can prolong the QTc interval by blocking potassium ion channels in the heart's electrical system, a known effect documented in official warnings. This change can increase the risk of a severe heart rhythm problem called Torsade de pointes.


Q: Does Metadon Hemofarm affect fertility?

Official reports of adverse reactions include the endocrine disorder called opioid-induced hypogonadism, which involves reduced sex hormone levels. This type of hormonal imbalance is medically linked to potential concerns regarding reduced fertility.


Q: What is the legal status of Metadon Hemofarm in different countries?

Methadone is legally classified as a controlled substance (e.g., Schedule II in the United States) by government agencies. This means its dispensing and use are subject to strict governmental regulation due to its high potential for abuse.


Q: Are there known drug interactions with HIV/AIDS medications?

Official documents warn that methadone interacts with drugs that affect the CYP enzyme system in the liver. Since many common HIV/AIDS medications are strong inhibitors or inducers of these enzymes, they can significantly increase or decrease methadone levels.


Q: What does the term 'maintenance treatment' mean?

Maintenance treatment refers to the use of methadone, often at a stable, consistent dose, as part of a longer, comprehensive treatment plan for opioid use disorder. This plan is documented in official guidelines to include counseling and behavioral therapies.


Q: Does Metadon Hemofarm show up on a drug test?

Methadone requires specific testing methods to be detected, separate from many standard drug screenings. Official drug testing protocols indicate it is typically detectable in urine for several days (up to a week) and for longer periods in hair.


Q: Can you drive while taking Metadon Hemofarm?

Official warnings state that due to the common risks of drowsiness, sedation, and dizziness, patients must be extremely cautious or avoid performing tasks that require mental alertness, such as driving or operating heavy machinery.


Q: What happens if a dose is missed?

If a dose is missed when the drug is taken for opioid addiction, official guidance notes the importance of a consistent daily schedule. If multiple doses are missed, professional guidance is required for appropriate instruction.


Q: What kind of withdrawal symptoms are associated with stopping Metadon Hemofarm?

Regulatory information indicates that withdrawal symptoms can occur when stopping methadone, including anxiety, agitation, muscle aches, insomnia, nausea, vomiting, and flu-like symptoms. Official labeling indicates that any reduction should be performed gradually under professional medical supervision.


Q: Can Metadon Hemofarm be taken with over-the-counter pain relievers?

Official guidance reports no concerning interactions with non-opioid over-the-counter pain relievers such as paracetamol (acetaminophen), ibuprofen, and aspirin. However, combining methadone with opioid-containing products, like codeine, is discouraged due to the risk of additive effects.


Q: Is it possible to develop a tolerance to Metadon Hemofarm?

Regulatory documents imply the possibility of developing tolerance, as the medication is an opioid and dosage guidelines stress the need for careful titration and dose adjustment. If tolerance is suspected, the need for adjustment is a clinical decision that must be made by a physician in accordance with official guidelines.


Q: Is Metadon Hemofarm a cure for addiction?

Official treatment protocols describe methadone as a medication approved to treat opioid use disorder (OUD). It is intended for stabilization and management as part of a comprehensive plan that includes counseling and behavioral therapies, not as a standalone cure.


Q: What happens if I stop taking Metadon Hemofarm suddenly?

Official warnings strongly discourage abruptly stopping methadone use, which can lead to severe and prolonged withdrawal symptoms due to the drug's long half-life. Regulatory warnings advise that cessation or reduction must be done gradually and only under professional medical supervision.


Q: Are there any major food or drink restrictions while taking this medicine?

Official regulatory warnings exist regarding the consumption of alcohol and grapefruit or grapefruit juice. These restrictions are in place due to the risk of dangerous central nervous system depression or increased methadone drug levels.

How should Metadon Hemofarm be stored and disposed of?

How to Store and Dispose of Metadon Hemofarm?

Methadone hydrochloride must be stored according to strict regulatory requirements to ensure product stability and prevent accidental poisoning. Due to the high risk of fatal overdose, especially in children, the medication must be kept out of the reach and sight of children in a secured location.

Storage Condition Requirement
Temperature Store at controlled room temperature, typically 20 C to 25 C.
Container Keep in the container dispensed, tightly closed, and protect from moisture and heat.

For disposal, unused or expired Metadon must be removed from the home immediately. The preferred method is using an authorized drug take-back program. If a take-back program is unavailable, the FDA advises immediately flushing the medicine down the toilet to eliminate the risk of accidental ingestion.

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

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