Caffeine impairs anticonvulsant effects of levetiracetam in the maximal electroshock seizure threshold test in mice.

Objectives: Caffeine is the most widely used psychoactive substance in the world. Animal studies indicate that acute caffeine exposure at high doses may induce seizures and diminish the anticonvulsant activity of antiepileptic drugs (AEDs) at much lower doses. The aim of the current study was to assess the effect of caffeine on the anticonvulsant action of levetiracetam (LEV) and vigabatrin (VGB).

Methods: The anticonvulsant activity of LEV and VGB was examined in the maximal electroshock seizure threshold test in mice (MEST test). All drugs were administered intraperitoneally by single injections, and caffeine was applied at doses capable of interfering with AEDs. Effects of caffeine exposure on AEDs were also investigated in tests of memory and motor performance.

Results: Caffeine reduced the protective effect of LEV against electroconvulsions. Total brain concentration of LEV was unaffected by caffeine as well as inversely; LEV had no significant impact on the brain caffeine concentration, suggesting a pharmacodynamic nature of the interaction between LEV and caffeine in the MEST test. VGB at applied doses did not affect the convulsive threshold. Administration of VGB, but not LEV, alone or in combination with caffeine, impaired memory retention. In the chimney test, the combined treatment with AEDs and caffeine did not cause motor coordination impairment.

Conclusions: It is suggested that caffeine may negatively affect the anticonvulsant action of LEV in patients with epilepsy.