Major
Alprazolam × Carbamazepine
Benzodiazepines. Short-to-medium-acting anxiolytics×Antiepileptics. Carboxamide derivatives
Mechanism
Carbamazepine induces CYP3A4; alprazolam plasma levels fall by 50%. Loss of anxiolytic effect and withdrawal symptoms (anxiety, insomnia, tremor) are possible.
Symptoms
Return of anxiety, insomnia, tremor, sweating, tachycardia (withdrawal). With high carbamazepine doses, full return of panic disorder symptoms is possible.
Management
During carbamazepine therapy, increase alprazolam by 50% or switch to lorazepam/oxazepam (glucuronidated, no CYP3A4 dependence). Alternative anticonvulsants without induction: levetiracetam, lamotrigine.