Morphine Toxicity Management
Clinical Manifestations
- CNS manifestations of morphine toxicity include drowsiness, cognitive impairment, confusion, hallucinations, and myoclonic jerks, often caused by accumulation of toxic opioid metabolites, particularly morphine-6-glucuronide (M6G), as reported by the American Society of Clinical Oncology 1, 2, 3
- Hypotension is the major adverse cardiovascular reaction, especially with volume depletion or concurrent vasodilator therapy, according to the American College of Cardiology 4, 5, 6, 7
- Nausea and vomiting occur in approximately 20% of patients, as noted by the American College of Cardiology 4, 5, 7
- Bowel dysfunction, including constipation, bloating, and incomplete evacuation, is a common side effect, as reported by the American Society of Clinical Oncology 1, 2, 3
- Pruritus is a possible side effect, as noted by the American Society of Clinical Oncology 1, 2, 3
Special Populations at Higher Risk
- Elderly trauma patients are particularly vulnerable to morphine accumulation with subsequent over-sedation and respiratory depression, requiring careful dose titration and close monitoring, as reported by the World Journal of Emergency Surgery 8, 9
- Elderly patients, particularly those with renal impairment, should start with substantially lower doses, as recommended by the World Journal of Emergency Surgery 8, 9
Management of Morphine Toxicity
- Naloxone (0.4 to 2.0 mg IV) is the specific antidote for respiratory depression from morphine overdose, as recommended by the American College of Cardiology 4, 5, 7
- Opioid dose reduction is the first-line approach for CNS toxicity symptoms, as reported by the American Society of Clinical Oncology 1, 2, 3
- Switching to another opioid agonist and/or another route may improve adverse effects, especially for CNS toxicity like OIH/allodynia and myoclonic jerks, as noted by the American Society of Clinical Oncology 1, 2, 3
- Metoclopramide and antidopaminergic drugs can be used for nausea/vomiting, as reported by the American Society of Clinical Oncology 1
- Laxative therapy (combination of stool softener and stimulant laxative) should be prescribed prophylactically, as recommended by the World Journal of Emergency Surgery 8, 9