Modafinil, is a wake-promoting drug approved by Food and Drugs Administration (FDA) for narcolepsy and sleep-apnoe syndrome. Although the mechanism underlying its arousal action remains elusive, it is known to increase glutamatergic, histaminergic, noradrenergic and dopaminergic transmission and decrease GABA release in different regions of the brain, which are all known to be involved in pathophysiology of epilepsy. In the present study, the effects of modafinil on pentylenetetrazol (PTZ) induced convulsive epilepsy were investigated in rats. Five experimental groups were formed for this purpose and each group was administered five different doses of modafinil (1, 2, 4, 45, 180 mg/kg, i.p) for seven days. All groups were administered PTZ (80 mg/kg, i.p) 2 hours after the final dose and the epileptic seizure activity was evaluated. According to the results; we detected that modafinil delayed the onset of the first myoclonic jerk and decreased the total major seizure period between 2-180 mg/kg doses and did not affect the major seizure onset period at any of the doses administrated. These results imply that modafinil exerts a dose dependent antiepileptic effect on PTZ induced convulsive epilepsy in rats (Tab. 1, Fig. 3, Ref, 42). Text in PDF www.elis.sk.