THE EFFECT OF REPEATED-DOSE ACTIVATED-CHARCOAL ON THE PHARMACOKINETICS OF SODIUM VALPROATE IN HEALTHY-VOLUNTEERS

Aims We investigated the effects of repeated-dose charcoal administere d several hours after sodium valproate on the pharmacokinetics of a si ngle dose of the drug in healthy volunteers. Methods The pharmacokinet ics of sodium valproate were studied in seven healthy volunteers after administration of a syrup (300 mg) on two occasions, one of which was followed by administration of repeated doses of oral charcoal startin g 4 h after the drug up to 32 h (total dose 80 g). Results Valproate w as rapidly absorbed with maximum concentrations Ih after administratio n. The area under the plasma concentration-time curve to 48 h (AUG (0, 48 h)) was 408 +/- 114.5 (s.d.) mg l(-1) h in the control phase and 39 8 +/- 108.6 mg l(-1) h after charcoal and the t(1/2) elimination was 2 0 +/- 6.8 h in the control phase, and 22 +/- 9.2 h after charcoal (NS) . Conclusions Repeated-dose activated charcoal does not appear to enha nce the rate of elimination of sodium valproate after therapeutic dose s of the drug and any beneficial effect of charcoal in overdose may be to prevent absorption of valproate still present in the gut.