Major
Gabapentin × Tramadol
Gabapentinoids (antiepileptics)×Other opioids
Mechanism
Additive CNS depression. Gabapentin does not lower the seizure threshold, but opioid-gabapentinoid combinations are associated with respiratory depression risk, 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
The combination is possible in neuropathic pain. Keep doses minimal, start low. Warn the patient about drowsiness and ataxia. Older patients: enhanced fall monitoring.