Overview
MITIGO is a concentrated morphine sulfate injection for intrathecal or epidural infusion via continuous microinfusion devices. It is indicated for severe, intractable chronic pain requiring opioid analgesia when less invasive methods are inadequate. This neuraxial administration delivers potent analgesia directly to the central nervous system with specific risks requiring expert management.
Mechanism of Action
Morphine is a full opioid agonist that binds primarily to mu-opioid receptors in the central nervous system. It alters pain perception and emotional response by inhibiting neurotransmitter release, decreasing pain signal transmission, and producing analgesia, sedation, and euphoria.
Indications
- Management of intractable chronic pain severe enough to require opioid analgesia
- When less invasive pain control methods are inadequate
- For continuous intrathecal or epidural infusion via microinfusion devices
Common Doses
- 200 mg/20 mL (10 mg/mL)
- 500 mg/20 mL (25 mg/mL)
Dosage
Initial dosing requires hospitalization with test doses of standard morphine. Epidural: 3.5-7.5 mg/day (opioid-naive) or 4.5-10 mg/day (opioid-tolerant). Intrathecal: 0.2-1 mg/day (opioid-naive) or 1-10 mg/day (opioid-tolerant). Doses often increase over time, with careful titration and monitoring. Intrathecal doses are typically 1/10 of epidural doses.
Black Box Warning
Black Box: Life-threatening respiratory depression requiring monitoring and naloxone availability
Contraindications
- Significant respiratory depression
- Acute or severe bronchial asthma in unmonitored settings
- Concurrent MAOI use or within 14 days
- Known or suspected gastrointestinal obstruction/paralytic ileus
- Hypersensitivity to morphine
- Infection at injection site
- Concomitant anticoagulant therapy
- Uncontrolled bleeding diathesis
Side Effects
- Respiratory depression (most serious)
- Nausea, vomiting, constipation
- Pruritus, urticaria
- Urinary retention
- Sedation, dizziness, confusion
- Myoclonus, seizures
- Hypotension
- Inflammatory masses with intrathecal infusion
- Adrenal insufficiency
- Androgen deficiency
- Serotonin syndrome with concomitant serotonergic drugs
Interactions
- Benzodiazepines/CNS depressants: Increased respiratory depression, sedation, death
- MAOIs: Serotonin syndrome, opioid toxicity
- Serotonergic drugs: Serotonin syndrome
- Mixed agonist/antagonist opioids: Reduced analgesia, withdrawal
- Muscle relaxants: Enhanced respiratory depression
- Anticholinergics: Increased urinary retention/constipation
Counseling Points
- This medication carries high addiction and overdose risks
- Report any difficulty breathing or extreme drowsiness immediately
- Do not drive or operate machinery while taking this medication
- Avoid alcohol and other CNS depressants
- Report increased pain or new neurological symptoms
- Follow strict aseptic technique for device care
- Understand signs of opioid withdrawal if medication is reduced