“ Caffeine (1–7.5 mg/kg) significantly reduced the antinociceptive effects of levetiracetam (25 …/kg) (first phase P = 0.002, second phase P < 0.001) and sumatriptan (2.5 mg/kg) (first phase P = 0.014, second phase … = 0.027); dose-dependent inhibition was observed in the second phase.”