Major
Pregabalin × Tramadol
Gabapentinoids (antiepileptics)×Other opioids
Mechanism
Similar to tramadol + gabapentin: additive CNS depression, seizure risk (tramadol lowers threshold). FDA issued a 2019 warning about respiratory depression with opioid-gabapentinoid combinations.
Symptoms
Drowsiness, sedation, slowed breathing. Seizures (tramadol) and syncope from orthostatic hypotension are possible. 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. Alternative opioid for neuropathic pain: pure opioid agonist (morphine, oxycodone) without serotonergic activity.