Twice‐daily dosing of valproate with divalproex

Equivalent doses of enteric‐coated divalproex were substituted for valproic acid in 15 epileptic patients who were on a three‐ or four‐times‐a‐day dosing schedule. After 2 wk the dosing regimen was changed to twice‐daily divalproex dosing, and plasma levels were determined during the 12‐hr period after the morning dose. Peak absorption was reached at 4 hr; extended plateaus were noted thereafter. The mean fluctuation between low and high plasma values for the group was 46%, with a decrease of less than 50% of peak levels in 9 of the 15 patients at a sampling time just before the second dose. Breakthrough seizures did not occur as a result of twice‐daily dosing. Clinical Pharmacology and Therapeutics (1983) 34, 501–504; doi: 10.1038/clpt.1983.204