Major
Haloperidol × Morphine
First-generation antipsychotics. Butyrophenone derivatives×Natural opium alkaloids
Mechanism
Additive CNS depression and sedation. Severe hypotension and respiratory depression have been reported, especially in older patients.
Symptoms
Drowsiness, slowed breathing (rate below 12/min), cyanosis of lips. Severe cases include respiratory arrest. Older patients: fall risk.
Management
Avoid the combination in older patients. For opioid-induced nausea, use ondansetron (no QT issue in short courses in older patients) or metoclopramide. For acute delirium, dexmedetomidine (no respiratory depression).
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.