Influence of lithium on the anticonvulsant activity of carbamazepine

The present study was undertaken to see whether the recently reported synergism between lithium and carbamazepine (CBZ) in mania also extends against convulsions. The anti-convulsant effect of various doses of CBZ was assessed in albino rats pretreated with vehicle or lithium salt (0.54 mEg/kg/day, p.o. for 9 days). The animals were subjected to 3 tests: maximum electro shock seizures (MES); minimum electro convulsive thresholds (MET) and pentylenetetrazol (PTZ)-induced convulsions: abolition of hind limb extension after electro shock, increases in the MET for appearance of neck jerk and absence of convulsions for one hr after PTZ were taken as parameters of the anticonvulsive effect respectively. In the MES and MET tests lithum did not alter the anticonvulsive effect of CBZ. Lithium, however, potentiated the anticonvulsant effect of CBZ against PTZ-induced convulsions.