To the Editor.
—We read with interest the article by Rosenfeld et al1 concerning valproic acid loading during intensive monitoring. We published an article about this interesting problem,2 reporting our pharmocologic experience with a single loading dose of valproate sodium. The study population consisted of five nonepileptic inpatients who received a single loading dose of 20 mg/kg of a solution of valproate sodium, first orally and then, five days later, rectally. Blood levels were measured more often than in the study by Rosenfeld and coworkers, ie, 10, 30, 60, and 120 minutes and 24 hours after administration. We observed that maximal concentration was higher after oral administration (105 mg/L) than after rectal administration (70 mg/L); the time to achieve serum concentrations of the drug greater than 50 mg/L was shorter orally (18 minutes) than rectally (58 minutes). For both types of administration, there were no variations in serum
Giroud M, Dumas R. Pharmacokinetics of Valproate in Adults After a Single Loading Dose. Arch Neurol. 1989;46(1):13–14. doi:10.1001/archneur.1989.00520370015008