PHYSEPTONE

What it is

PHYSEPTONE is an oral solution of 5 mg/mL methadone hydrochloride. It is a bright amber coloured syrup with an aromatic odour. The active ingredient is methadone hydrochloride.

Approved indications

— Treatment of dependence on opioid drugs. — Management of severe pain where other treatment options have failed, are contraindicated, not tolerated or are otherwise inappropriate to provide sufficient management of pain, the pain is opioid-responsive, and requires daily, continuous, long-term treatment. PHYSEPTONE is not indicated for use in chronic non-cancer pain other than in exceptional circumstances. PHYSEPTONE is not indicated as an as-needed (PRN) analgesia.

Dosing overview

For treatment of dependence on opioid drugs, a dose of 10 to 20 mg by mouth may be given initially and increased as necessary by 5 to 10 mg daily. The dose must not be increased by more than 5 to 10 mg daily, and by no more than 30 mg in any seven day period. After stabilisation, which can often be achieved with a daily dose of 30 to 50 mg daily (up to a maximum of 80 mg daily), the dose of methadone is gradually decreased until total withdrawal is achieved. For treatment of severe pain in adults, the usual single dose is 5–10 mg by mouth, and the usual initial dose should be 5–10 mg 6–8 hourly, later adjusted to the degree of pain relief obtained. In chronic use, methadone should not be administered more than twice daily. Methadone is not recommended for use in children and adolescents aged less than 18 years, since documented clinical experience has been insufficient to establish a suitable dosage regimen; furthermore, children are particularly sensitive to the respiratory and central nervous system depressant effects of methadone.

Key safety warnings

Serious, life-threatening or fatal respiratory depression may occur with the use of PHYSEPTONE. Be aware of situations which increase the risk of respiratory depression, modify dosing in patients at risk and monitor patients closely, especially on initiation or following a dose increase. Concomitant use of opioids with benzodiazepines, gabapentinoids, antihistamines, tricyclic antidepressants, antipsychotics, cannabis or other central nervous system (CNS) depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death. Limit dosages and durations to the minimum required; and monitor patients for signs and symptoms of respiratory depression and sedation. Methadone inhibits cardiac potassium channels and prolongs cardiac repolarisation (that is, prolongs the QT interval). QT interval prolongation and serious arrhythmia (Torsade de Pointes) have been observed during treatment with methadone and appear to be more common with higher doses. PHYSEPTONE poses risks of hazardous and harmful use which can lead to overdose and death. Assess the patient's risk of hazardous and harmful use before prescribing and monitor the patient regularly during treatment. Accidental ingestion or exposure of PHYSEPTONE, especially by children, can result in a fatal overdose of methadone. Patients and their caregivers should be given information on safe storage and disposal of unused PHYSEPTONE.

Contraindications

PHYSEPTONE is contraindicated in individuals who are hypersensitive to methadone or other components of the oral liquid. Methadone is contraindicated in patients with severe respiratory disease, acute respiratory disease and respiratory depression, especially in the presence of cyanosis and excessive bronchial secretions. Methadone should not be given during an attack of bronchial asthma. Methadone is contraindicated in the presence of acute alcoholism, head injury and raised intracranial pressure. Methadone is contraindicated in individuals receiving monoamine oxidase inhibitors or within 14 days of stopping such treatment. Methadone should not be administered to patients with severe hepatic impairment as it may precipitate hepatic encephalopathy. Methadone is contraindicated in individuals with existing QT prolongation, including those with congenital long QT syndrome.

PBS listing

The injection containing methadone hydrochloride 10 mg in 1 mL is listed on the PBS as 2 items with authority required restriction, with an ex-manufacturer price of A$33.18, latest schedule 2026-05-01.

Regulatory history

PHYSEPTONE methadone hydrochloride 5 mg/mL oral liquid was first listed on the ARTG on 2023-03-27. The medicine was first approved on 22 June 1994.