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Methadone oral solution


Oral liquid formulations of methadone hydrochloride.

Drugs List

  • methadone 1mg/ml oral solution
  • methadone 1mg/ml oral solution sugar-free
  • METHAROSE brown 1mg/ml oral solution sugar-free
  • PHYSEPTONE 1mg/ml mixture
  • PHYSEPTONE 1mg/ml oral solution sugar-free
  • Therapeutic Indications


    Opioid drug dependency - treatment
    Pain - moderate to severe

    Unlicensed Uses

    Treatment of neonatal opioid withdrawal



    Treatment of Addiction
    Initial daily dose: 10mg to 20mg.
    Increase by 10mg to 20mg a day until signs of intoxication or withdrawal are no more. The usual daily dose range is 40mg to 60mg but should be adjusted according to individual response with the aim of gradual dose reduction.

    The following alternative dosing schedule may be suitable:
    Initial daily dose: 10mg to 30mg, if tolerance is high an initial daily dose of up to 40mg may be prescribed.
    Then during the first week increase by 5mg to 10mg a day until signs of intoxication or withdrawal are no more. Maximum weekly increase is 30mg.
    After the first week increase up to the usual daily dose range of 60mg to 120mg, adjust according to individual response.

    Treatment of Moderate to Severe Pain
    5mg to 10mg every 6 to 8 hours, adjusted based on individual patient response. Patients on long term use not to be given more frequently than every 12 hours.


    Neonatal Opioid Withdrawal (Unlicensed)
    Initial dose: 100micrograms/kg.
    Then increase dose by 50micrograms/kg every 6 hours until symptoms are controlled.
    Once a daily maintenance dose that controls the symptoms has been found, give in 2 divided doses.

    Patients with Renal Impairment

    The Renal Drug Handbook offers the following dosages in renal impairment: GFR less than 10ml/minute: 50% to 75% of normal dose, and titrate according to response.


    Acute alcohol intoxication
    Children 1 month to 18 years
    Risk of paralytic ileus
    Within 2 weeks of discontinuing MAOIs
    Acute asthma
    Acute respiratory depression
    Biliary tract disorder
    Head trauma
    Long QT syndrome
    Non-opioid drug dependence
    Obstructive pulmonary disease
    Raised intracranial pressure
    Renal tract spasm
    Severe hepatic disorder
    Torsade de pointes
    Ulcerative colitis

    Precautions and Warnings

    Family history of long QT syndrome
    Family history of sudden death
    Females of childbearing potential
    Tobacco smoking
    Active liver disease
    Adrenal insufficiency
    Benign prostatic hyperplasia
    Brain damage
    Drug misuse
    Electrolyte imbalance
    Gastrointestinal obstruction
    Glucose-galactose malabsorption syndrome
    Hereditary fructose intolerance
    History of alcohol abuse
    History of drug misuse
    History of torsade de pointes
    Inflammatory bowel disease
    Ischaemic heart disease
    Mild hepatic impairment
    Myasthenia gravis
    Psychiatric disorder
    Reduced respiratory reserve
    Renal impairment

    Correct electrolyte disorders before treatment
    May cause hepatic encephalopathy in patients with hepatic disease
    May exacerbate asthma
    Reduce dose in patients with hepatic impairment
    Reduce dose in patients with renal impairment
    Advise patient ability to drive or operate machinery may be impaired
    Advise patient not to drive until they know how the medicine affects them
    Advise patient this medicine is subject to driving restrictions
    Not all available brands are licensed for all indications
    Oral solution with maltitol unsuitable in hereditary fructose intolerance
    Presentations with sorbitol unsuitable in hereditary fructose intolerance
    Some brands contain Quinoline Yellow (E104) : May cause allergic reactions
    Some brands contain Sunset Yellow (E110) - can trigger allergic reactions
    Some formulations contain benzoic acid
    Some formulations contain hydroxybenzoate
    Some formulations contain propylene glycol
    Some formulations contain sucrose
    Some formulations contain tartrazine
    Some formulations may contain alcohol
    Perform ECG before and during treatment
    Perform liver function tests before commencing therapy and during therapy
    Monitor blood glucose during dose escalation
    Monitor for constipation; give laxatives as required
    Monitor patients with a history of alcoholism and drug abuse
    Monitor patients with hepatic impairment
    Monitor patients with renal impairment
    Monitor serum electrolytes
    Neonate exposed in utero: Monitor for respiratory depression
    Tolerance and dependence may occur
    Consider dose reduction or change in opioid if evidence of hyperalgesia
    High addiction potential
    Neonate exposed in utero: Risk of visual disorder
    Predisposition QT prolongation: Counsel patient on symptoms of arrhythmias
    Prolonged use at high doses may result in hyperalgesia
    May affect results of some laboratory tests
    Avoid abrupt withdrawal
    To discontinue, reduce dose gradually
    Dose adjustment required if patient starts/stops smoking during therapy
    Advise patient not to take St John's wort concurrently
    Advise patient to avoid alcohol during treatment
    Advise that effects are potentiated by CNS depressants (including alcohol)
    Advise patient grapefruit products may increase plasma level
    Female: Ensure adequate contraception during treatment

    Methadone can produce drowsiness and reduce consciousness, although tolerance to these effects can occur after repeated use.

    Before commencing treatment with methadone hydrochloride, a strategy should be constructed with the patient for ending treatment in order to reduce the risk of addiction and drug withdrawal syndrome. Maintaining an active opioid prescription should be an active decision agreed between the patient and clinician and reviewed a minimum of every 3 months.

    A full patient history should be established to document concomitant medications and past and present medical and psychiatric conditions. The risk of developing tolerance to methadone should be explained to the patient prior to treatment. All patients should be closely observed for signs of misuse, abuse or addiction. Patients at risk of opioid misuse may require additional support and monitoring.

    Tobacco smoke induces the cytochrome P450 isoenzyme CYP1A2, by which methadone is metabolised. This may result in reduced methadone plasma level. Dosage adjustment may be required if a patient starts or stops smoking during methadone therapy.

    Accumulation is possible due to its long half-life, particularly in the elderly and debilitated. A single dose to relieve symptoms may lead to accumulation and possible death if repeated on a daily basis.

    In patients without recognised risk factors for QT prolongation, monitor ECG before dose titration above 100mg/day and at seven days after titration.

    Some brands contain propylene glycol. Due to the associated adverse affects reported in patients like renal dysfunction, acute renal failure and liver dysfunction, patients with renal or hepatic impairment should be monitored throughout treatment.

    Due to the risk of concomitant use of methadone and sedatives, patients should only take sedative medicines where alternative treatment options are not possible. In these patients, sedation levels and signs of respiratory depression should be closely monitored.

    Pregnancy and Lactation


    Use methadone with caution during pregnancy.

    The manufacturer advises caution if methadone is used during pregnancy. Methadone should only be used in pregnancy if the potential benefits outweigh the risks. Use of methadone throughout pregnancy often leads to drug dependence in the foetus. 60%-90% of infants exposed in utero to methadone experience withdrawal symptoms which becomes evident shortly after birth, usually within 48 hours but can be delayed up to 7-14 days (Briggs, 2015). In such cases, advise the mother of the risk of neonatal opioid withdrawal syndrome and ensure necessary treatment will be available.

    The manufacturer recommends that a careful assessment should be carried out before administration of methadone due to the risks to the foetus including respiratory depression, low birth weight and neonatal withdrawal syndrome.


    Use methadone with caution during breastfeeding.

    The manufacturer advises caution if methadone is used when breastfeeding. Methadone is known to be excreted into breast milk at low levels. When considering breastfeeding, clinical specialist advice should be taken into account. If breastfeeding is considered, the dose should be as low as possible. The breastfeeding mother should be advised to monitor the infant for sedation and difficulties breathing and to seek immediate medical care at the first instance.

    It has been noted that breastfeeding may reduce the withdrawal response of the infant from methadone during pregnancy. If discontinuing breastfeeding is necessary, it should be gradual to avoid increased withdrawal symptoms in the infant.

    Effects on Ability to Drive and Operate Machinery

    This class of medicine is in the list of drugs included in regulations under 5a of the Road Traffic Act 1988 (England and Wales). This medicine may be subject to police testing and has specified maximum blood levels for driving. When prescribing this medicine: Advise patient the medicine can affect cognitive function and is likely to affect ability to drive. Advise patient not to drive until they know how the medicine affects them. It is an offence to drive while under the influence of this medicine. However, a patient is not committing an offence (called 'statutory defence') if: 1. The medicine has been prescribed to treat a medical or dental problem and 2. The medicine has been taken according to the instructions given by the prescriber and/or in the information provided with the medicine, and 3. The medicine was not affecting the ability to drive safely. For further guidance see

    Side Effects

    Anti-diuretic effect
    Biliary spasm
    Cardiac arrest
    Difficulty in micturition
    Diminution of potency
    Dry eyes
    Dry mouth
    Dryness of nose
    Exacerbation of pre-existing asthma
    Facial flushing
    Increased prolactin
    Mood changes
    Muscle rigidity
    Postural hypotension
    Prolongation of QT interval
    Raised intracranial pressure
    Reduced libido
    Respiratory depression
    Sexual dysfunction
    Sleep disturbances
    Torsades de pointes
    Ureteric spasm
    Urinary retention
    Visual disturbances
    Weight gain

    Effects on Laboratory Tests

    Elevated levels of globulins and blood albumin have been noted in patients taking methadone.

    Methadone may result in false results during urine testing for pregnancy.

    Withdrawal Symptoms and Signs

    Some or all of the opioid drug withdrawal syndrome side effects are: restlessness, lacrimation, rhinorrhoea, yawning, perspiration, chills, myalgia, mydriasis and palpitations. Other symptoms may also develop including irritability, agitation, anxiety, hyperkinesia, tremor, weakness, insomnia, anorexia, abdominal cramps, nausea, vomiting, diarrhoea, increased blood pressure, increased respiratory rate or heart rate.

    When a patient no longer requires treatment, it is advisable to taper the dose gradually to minimise symptoms of withdrawal. Tapering from a high dose may take weeks to months.


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: February 2022

    Reference Sources

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 10th edition (2015) ed. Briggs, G., Freeman, R. Wolters Kluwer Health, Philadelphia.

    Summary of Product Characteristics: Methadone 1 mg/ml Oral solution BP-Sugar Free. Thornton & Ross Ltd. Revised April 2015.
    Summary of Product Characteristics: Methadone Mixture 1 mg/ml. Thornton & Ross Ltd. Revised March 2015.

    Summary of Product Characteristics: Methadone 1 mg/ml Oral solution Sugar Free. Martindale Pharmaceuticals Ltd. Revised October 2021.
    Summary of Product Characteristics: Methadone Mixture DTF 1 mg/ml Physeptone Mixture. Martindale Pharmaceuticals Ltd. Revised May 2020.

    Summary of Product Characteristics: Methadone Hydrochloride DTF 1 mg/ml Oral solution. Rosemont Pharmaceuticals Ltd. February 2022.
    Summary of Product Characteristics: Methadone Hydrochloride Sugar Free 1 mg/ml Oral solution. Rosemont Pharmaceuticals Ltd. Revised December 2021.
    Summary of Product Characteristics: Metharose Sugar Free 1 mg/ml Oral solution. Rosemont Pharmaceuticals Ltd. Revised December 2021.

    Summary of Product Characteristics: Physeptone Mixture 1mg/ml. Martindale Pharmaceuticals Ltd. Revised May 2020.
    Summary of Product Characteristics: Physeptone 1mg/ml Oral solution sugar-free. Martindale Pharmaceuticals Ltd. Revised October 2021. Government departments. Department for Transport. Publications. Drug driving and medicine: Advice for healthcare professionals. Drug driving: Guidance for healthcare professionals on drug driving. Available at: Last accessed: 18 February 2022

    NICE Evidence Services Available at: Last accessed: 18 February 2022

    Specialist Pharmacy Service (SPS)
    Available at:
    What are the clinically significant drug interactions with tobacco smoking? Last revised: July 2020
    Last accessed: 07 December 2020

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