Oxcarbazepine (OXC), widely used to treat focal epilepsy, is reported to exacerbate seizures in patients with generalized epilepsy. OXC is metabolized to monohydroxy derivatives in two enantiomeric forms: (R)-licarbazepine and (S)-licarbazepine. Eslicarbazepine acetate is a recently approved antiepileptic drug that is rapidly metabolized to (S)-licarbazepine. It is not known whether (S)-licarbazepine exacerbates seizures. Here, we test whether OXC or either of its enantiomers exacerbates the number of spike-and-wave discharges (SWDs) in mice harboring the human γ-aminobutyric acid A receptor (GABAA)γ2(R43Q) mutation. OXC (20 mg/kg), (S)-licarbazepine (20 mg/kg), and (R)-licarbazepine (20 mg/kg) all significantly increased the number of SWDs, while their duration was unaffected. The potential for (S)-licarbazepine to exacerbate SWDs suggests that eslicarbazepine acetate should be used with caution in generalized epilepsy. Furthermore, generalized seizure exacerbation for first-, second-, and third-generation carbamazepine-based compounds is likely to occur through a common mechanism.