Antinociceptive activity of sodium valproate in mice after chronic treatment.

1. Mice were given sodium valproate (0.71%) in the drinking fluid for 21 days. The antinociceptive activity, locomotor activity and body temperature changes were recorded at 7, 14 and 21 days. The possible carryover antinociceptive effects were also determined after valproate withdrawal for up to 3 days after 7-, 14- and 21-day treatment. 2. The antinociceptive activity was present only on days 7, 14 and 21 and, on withdrawal of the drug, the antinociceptive activity disappeared. 3. Thus, with this regimen of valproate administration, there was no persistent antinociceptive activity (carryover effect). There were essentially no effects of valproate on the locomotor activity and body temperature of mice. The antinociceptive effects were due to the presence of the drug and disappeared on valproate's withdrawal.

Evaluation of the antiinflammatory activity of sodium valproate in rats and mice.

1. Treatment of rats with sodium valproate (100, 200 and 400 mg/kg i.p.) reduced the paw oedema induced by carrageenan by 36, 15 and 48%, respectively, within 3 h . 2. The effect produced by the higher dose (400 mg/kg) was equivalent to that produced by indomethacin (100 mg/kg). At 100 and 400 mg/kg, sodium valproate decreased the granuloma formation by a significant level. Similar doses of sodium valproate did not affect the rectal temperature in yeast-fevered mice, except with a dose of 200 mg/kg, which showed a significant decrease at 180 and 240 min posttreatment. 3. In comparison, sodium salicylate reduced the hyperthermia very significantly throughout the study period. 4. In normothermic mice, the rectal temperature changed only with a 400 mg/kg dose, but did not respond to lower SV doses. 5. The results indicate that sodium valproate, useful clinically as an epileptic drug, may have a potential therapeutic use as a mild antiinflammatory agent.