Major
Morphine × Quetiapine
Natural opium alkaloids×Atypical antipsychotics
Mechanism
Additive CNS and respiratory depression. Quetiapine potentiates opioid sedation. Older patients: fall and aspiration risk.
Symptoms
Drowsiness, slowed breathing (rate below 12/min), cyanosis of lips. Severe cases include respiratory arrest. Older patients: fall risk.
Management
The combination is possible in palliative care with careful monitoring. Keep doses minimal. Older patients: cap quetiapine at 25–50 mg at night. Alternative antipsychotic for delirium: dexmedetomidine or low-dose haloperidol.