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).
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.