Morphine sustained-release (MSR) oral

Therapeutic action

Centrally acting opioid analgesic.

Indications

Severe and persistent pain, especially cancer pain.

Forms and strengths

• 10 mg, 30 mg, and 60 mg sustained-release capsules or tablets.

Dose

Adjust the dose if necessary, increasing by 50% per day until pain relief is obtained.

• Usually, the effective daily dose is determined during initial treatment with immediate-release morphine. When changing from MIR to MSR, the daily dose remains the same.
• Example: if the effective dose of MIR is 20 mg every 4 hours (120 mg daily), the dose of MSR is 60 mg every 12 hours.
• If treatment is initiated directly with MSR: child over 6 months initially 0.5 mg/kg every 12 hours; adult initially 30 mg every 12 hours.
• Patients stabilized on MSR may require rescue doses of MIR for breakthrough pain. A rescue dose corresponds to 10% of the daily MSR dose.
• If a patient regularly requires more than 3 rescue doses per day, increase the daily MSR dose by the sum of rescue doses.

Duration

According to clinical response. Do not stop long-term treatment abruptly; decrease doses progressively to avoid withdrawal symptoms.

Contra-indications, adverse effects, precautions

• Do not administer to patients with severe respiratory impairment or decompensated hepatic impairment.
• Do not initiate treatment with the sustained-release formulation in elderly patients or those with renal or hepatic impairment. Begin with MIR.
• May cause dose-related sedation and respiratory depression, nausea, vomiting, constipation, urinary retention, confusion, raised intracranial pressure, and pruritus.
• In overdose, excessive sedation, respiratory depression, and coma may occur.
• Administer with caution to patients with respiratory impairment, head injury, raised intracranial pressure, uncontrolled epilepsy, or urethroprostatic disorders.
• Do not combine with mixed agonist-antagonist opioids such as buprenorphine, nalbuphine, or pentazocine.
• Sedation and respiratory depression are increased when combined with alcohol and central nervous system depressants.
• Pregnancy and breast-feeding: no contra-indication, but administer with caution at the lowest effective dose and monitor the child when exposure is near delivery or during breast-feeding.