Metadon Alkaloid 10 mg/mL oral drops and oral solution – methadone for the treatment of opiate dependence

Metadon Alkaloid is a medicine containing methadone hydrochloride, an opioid that binds to opioid receptors in the central nervous system. It is used in the treatment of opiate dependence – it prevents or relieves the withdrawal symptoms that occur after stopping opiates.

In Serbia, two forms of the same strength (10 mg methadone hydrochloride per 1 mL) are authorised under the name Metadon Alkaloid: oral drops, solution (10 mL bottle, 1 mL = 30 drops) and oral solution (100 mL or 1000 mL bottle). Both forms are taken by mouth, strictly as instructed by the doctor.

How does Metadon Alkaloid work and how is it taken correctly in the treatment of opiate dependence?

Key facts about the medicine

What is Metadon Alkaloid used for?

According to the patient leaflet, Metadon Alkaloid is used in the treatment of opiate dependence (suppression of the narcotic withdrawal syndrome): it prevents or relieves withdrawal symptoms resulting from stopping opiates.

The medicine must not be used in children, and use in adolescents under 18 years is not recommended.

How is Metadon Alkaloid taken and dosed?

The dose is set and changed only by the doctor. Usual adult dosing according to the leaflet:

• Starting dose: 10–20 mg daily (1–2 mL; for drops this is 30–60 drops).
• Dose increase: by 10–20 mg (1–2 mL, i.e. 30–60 drops) daily until withdrawal symptoms are controlled.
• Stabilisation: usually reached with a daily dose of 40–60 mg (4–6 mL, i.e. 120–180 drops); higher doses are sometimes needed.
• Once the patient is stabilised, the doctor may gradually reduce the dose depending on the degree of dependence.
• The medicine is for oral use. According to the information for healthcare professionals, it is recommended that each dose is added to water or juice to prevent misuse by injection.
• The doctor should discuss continuation of treatment with you at regular intervals; if treatment is stopped, a plan for gradual dose reduction is made.

Special patient groups

• Children and adolescents: the medicine must not be used in children; it is not recommended under 18 years.
• Elderly (> 65 years) and very ill patients: they are more sensitive to the medicine; because of its long elimination half-life it may accumulate – the doctor gives the lowest possible dose and monitors more closely.
• Liver or kidney impairment: the doctor adjusts (reduces) the dose and monitors the patient more closely.
• Risk of QT prolongation: methadone is used with caution.

Contraindications – when the medicine must not be used

• allergy to methadone or any of the excipients;
• breathing difficulties or asthma (the medicine must not be used during an asthma attack);
• dependence on alcohol or on other drugs;
• concomitant treatment with MAO inhibitors or stopping them less than 2 weeks ago;
• labour;
• phaeochromocytoma (adrenal gland tumour);
• paralytic ileus (bowel paralysis);
• raised intracranial pressure or recent head injury;
• children.

Warnings and precautions

• Regular use, especially long-term, can lead to dependence; withdrawal symptoms on sudden stopping include restlessness, insomnia, irritability, anxiety, palpitations, high blood pressure, nausea, vomiting, diarrhoea, chills, tremor and sweating.
• Opioids should be taken only by the person they were prescribed for; higher or more frequent doses increase the risk of dependence, overdose and death.
• Talk to your doctor if you have liver, kidney, gallbladder or bile duct disease, epilepsy, an underactive thyroid, adrenal gland disease, an enlarged prostate, low blood pressure, shock, myasthenia gravis or bowel disease.
• Be sure to tell your doctor if you have or have had a heart rhythm disorder or heart disease, if anyone in your family died suddenly without an obvious cause, or if you have low potassium, sodium or magnesium in your blood.
• Weakness, tiredness, loss of appetite, nausea, vomiting or low blood pressure may be a sign of low cortisol production – contact your doctor.
• Long-term use may lower sex hormone levels and increase prolactin (reduced libido, impotence, absence of periods).
• The medicine contains sorbitol (a source of fructose) – if you are intolerant to some sugars, consult your doctor.

Interactions with other medicines, food and drink

• MAO inhibitors – the medicine must not be taken at the same time or within 2 weeks after stopping them.
• Benzodiazepines and other sedatives, sleeping medicines and anaesthetics – risk of drowsiness, respiratory depression, coma and death.
• Antidepressants (citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, duloxetine, venlafaxine, amitriptyline, clomipramine, imipramine, nortriptyline) and serotonergic medicines – risk of serotonin syndrome (agitation, hallucinations, fast heartbeat, fever, muscle stiffness, nausea, diarrhoea).
• Medicines affecting the heart and electrolytes – verapamil, enalapril, diuretics, lithium, mexiletine.
• Medicines that change methadone levels – cimetidine, rifampicin, phenytoin, carbamazepine, phenobarbital, primidone, HIV medicines (nevirapine, efavirenz, ritonavir, abacavir, nelfinavir), ciprofloxacin and macrolides (e.g. erythromycin), ketoconazole, voriconazole, fluconazole, St John's wort.
• Medicines that acidify the urine, such as ascorbic acid (vitamin C).
• Other opioids (codeine, pentazocine, morphine), naloxone, naltrexone and buprenorphine (may cause withdrawal symptoms), lofexidine and clonidine.
• Anti-nausea medicines (cyclizine, domperidone, metoclopramide, ondansetron), medicines for Parkinson's disease, atropine and metamizole.
• Alcohol – do not drink (it increases drowsiness). Grapefruit juice – do not drink, it may change the effect of the medicine.

Pregnancy and breast-feeding

• Pregnancy: the medicine is not taken during pregnancy unless the doctor judges that the benefit to the mother outweighs the risk to the child. The baby may become dependent and have withdrawal symptoms after birth. The medicine must not be taken during labour; it may affect the result of a pregnancy test.
• Breastfeeding: talk to your doctor. If you breastfeed, watch your baby – increased sleepiness, breathing difficulties or floppiness require immediate medical attention.

Driving and using machines

• Methadone has a major influence on the ability to drive and use machines (drowsiness, reduced alertness). According to the leaflet, driving and operating machines are not allowed during treatment until your doctor confirms that it is safe.

Possible side effects

• Very common: nausea or vomiting.
• Common: tiredness, drowsiness, weight gain, fluid retention, constipation, transient rash, increased sweating, blurred vision, constricted pupils, dry eyes, vertigo, euphoria, hallucinations.
• Uncommon: fainting, weakness, dizziness on standing (low blood pressure), headache, dysphoria, agitation, confusion, insomnia, itching, dry mouth or nose, inflamed tongue, facial flushing, breast enlargement and milk secretion, difficulty passing urine, cramps in the back and abdomen, swelling, hypothermia, reduced sex drive, menstrual disorders; for the drops, fluid in the lungs and bile duct disorder are also listed.
• Not known: loss of appetite, low platelet count, low magnesium, potassium or blood sugar, raised prolactin, reduced production of adrenal and sex hormones, involuntary eye movements, vision problems in children whose mothers took methadone in pregnancy, dependence.

Overdose, missed dose and stopping treatment

• Overdose: contact a doctor or the nearest healthcare facility immediately and take the pack with you. Signs include breathing difficulties, extreme drowsiness, loss of consciousness, pinpoint pupils, cold clammy skin, muscle weakness, low blood sugar, slow heartbeat and, in severe cases, breathing arrest, fall in blood pressure, cardiac arrest, coma and death.
• Missed dose: wait until the next dose is due and take only the prescribed dose. Do not take a double dose.
• Stopping treatment: do not stop without agreement with your doctor – the doctor will plan a gradual dose reduction. Tolerance is lost quickly after stopping, so a dose you were previously used to can be fatal.

Related information

For additional care and support with addiction, see also the category Substance abuse – products in this category do not replace the medicine you have been prescribed.

Composition, pack and manufacturer

• Active substance: methadone hydrochloride, 10 mg per 1 mL (for drops, 1 mL = 30 drops).
• Excipients: sorbitol, liquid (non-crystallising) (E420); glycerol (E422); sodium benzoate (E211); citric acid monohydrate (E330); purified water. The oral solution contains less than 1 mmol (23 mg) sodium per dose.
• Appearance: clear, colourless solution.
• Packs: oral drops – brown glass bottle with dropper, 10 mL; oral solution – brown glass bottle of 100 mL (with 5 mL graduated pipette) or 1000 mL.
• Marketing authorisation holder: Alkaloid d.o.o. Beograd, Prahovska 3, Belgrade; manufacturer: Alkaloid AD Skopje, Bulevar Aleksandar Makedonski 12, Skopje, North Macedonia.
• Authorisations: drops 10 mL – 515-01-02576-22-001 of 15 June 2023; oral solution 100 mL – 515-01-02578-22-001 and 1000 mL – 515-01-02579-22-001 of 4 April 2023.

Storage

• The medicine does not require any special storage conditions.
• After first opening the bottle, the shelf life is one month if stored at up to 25 °C.
• Shelf life of the unopened oral solution: 3 years.
• Keep out of the sight and reach of children.

Frequently asked questions

Why is Metadon Alkaloid dangerous for children and other people?

Methadone is highly toxic to anyone who has not developed tolerance to opioids: 50–100 mg can be fatal for a non-tolerant adult, and 10 mg (1 mL) can cause severe, fatal poisoning in a child. That is why the medicine is never given to others and is kept out of the reach of children.

What is the difference between the drops and the oral solution?

Both forms contain 10 mg methadone per 1 mL. The oral drops (10 mL bottle, 30 drops = 1 mL) are dispensed on a prescription in two copies, while the oral solution in 100 mL and 1000 mL bottles is used in inpatient healthcare institutions.

May I drink alcohol or grapefruit juice during treatment?

No. Alcohol increases drowsiness and dangerously slows breathing, and grapefruit juice may change the effect of methadone.

What if I want to stop treatment?

Do not stop suddenly. Talk to your doctor, who will plan a gradual dose reduction. After stopping, tolerance disappears quickly, so taking your previous dose again can be fatal.

Sources

• ALIMS – Patient information leaflet (PIL): Metadon Alkaloid 10 mg/mL oral drops, solution
• ALIMS – Summary of product characteristics (SmPC): Metadon Alkaloid 10 mg/mL oral drops, solution
• ALIMS – Patient information leaflet (PIL): Metadon Alkaloid 10 mg/mL oral solution
• ALIMS – Summary of product characteristics (SmPC): Metadon Alkaloid 10 mg/mL oral solution

Date sources were checked: 25.10.2026.