Major
citalopram × Tramadol
SSRI (selective serotonin reuptake inhibitor)×Other opioids
Mechanism
Dual risk. Citalopram (SSRI) raises synaptic serotonin and prolongs QT. Tramadol blocks serotonin and norepinephrine reuptake and lowers seizure threshold. Effects add up.
Symptoms
Serotonin syndrome: agitation, confusion, tremor, myoclonus, hyperreflexia. Autonomic features: sweating, tachycardia, hypertension, fever. First signs appear within hours of co-administration.
Management
Avoid the combination. For analgesia on citalopram, use paracetamol, an NSAID, or morphine/oxycodone. For neuropathic pain, gabapentin or pregabalin.