Mefloquine significantly modifies the total spectral power of the EEG and some parameters of the epileptiform activity induced by pentylenetetrazole. Mefloquine (MFQ) (40 mg/kg) significantly decreased the total spectral power and modified the epileptiform activity in rats administered with pentylenetetrazole (PTZ). A) Total spectral power acquired in the frequency ranges of 0–32 Hz; error bars represent SEM. B) Representative EEG traces obtained in 10-seconds epochs during basal recording and post-administration of vehicle or MFQ and PTZ. C) Duration, D) Amplitude and E) Frequency of the epileptiform activity induced by PTZ. MFQ significantly modified these parameters. *p < 0.05 statistically significant compared with the control group (vehicle + PTZ). #p < 0.05 statistically significant compared with the basal recording. The total spectral power was analyzed using a Nonparametric Kruskal-Wallis analysis followed by Student Newman Keuls test. The duration, amplitude, and frequency were compared with a Mann–Whitney rank sum test. Vehicle + PTZ (n = 8), MFQ 40 mg/kg + PTZ (n = 8).