Major
Bupropion × Ciprofloxacin
Other antidepressants (NDRI)×Fluoroquinolone antibacterials
Mechanism
Ciprofloxacin blocks CYP1A2 and lowers seizure threshold itself. Bupropion is a potent proconvulsant. Ciprofloxacin also weakly blocks CYP2B6 (a minor bupropion route).
Symptoms
Seizures (generalised tonic-clonic or focal), agitation, tremor, insomnia. Patients with prior epilepsy or eating disorders are at particular risk.
Management
Avoid the combination, especially in patients with prior epilepsy. Alternative antibiotics: a cephalosporin, nitrofurantoin, or fosfomycin (no effect on seizure threshold).