Nifedipine potentiates gabapentin antinociception in rats

To evaluate the involvement of Ca++ channels in Gabapentin antinociception. In healthy male albino rats formalin (50 microliters, 5%) was injected at the planter surface of the paw. Pain score was calculated. Antinociceptive effect of (10, 30 mg/kg) gabapentin and (3, 10 mg/kg) nifedipine alone and on co-administration of sub analgesic doses was studied 30 minutes after formalin injection and reduction in pain scores was calculated. Gabapentin (30 mg/kg) and nifedipine (10 mg/kg) reduced the pain score in formalin injected rats. Gabapentin (10 mg/kg) and nifedipine (3 mg/kg) given alone did not modify pain score, however, on co-administration they significantly reduced the pain score. Study provides evidence of involvement of Ca++ channels in gabapentin antinociception.