• loading;
  • mania;
  • pharmacokinetics;
  • titration;
  • valproate

Objective:  This double-blind pilot study compares the effectiveness and incidence of adverse effects of oral loading versus titration schedules of valproate in acute mania.

Method:  Consecutive new admissions for an acute manic episode were prescribed either an oral loading dose (20 mg/kg/day; n=5; mean age=33.4) or slower titration dose (10 mg/kg/day; n=6, mean age=30.6) of valproate for 7 days without other psychotropic agents, with the exception of benzodiazepines. Daily outcome measures included: serum valproic acid levels, the Young Mania Rating Scale (YMRS), the Brief Psychiatry Rating Scale (BPRS), the Clinical Global Impression Scale (CGI) and the Adverse Effect Rating Scale.

Results:  The mean serum valproic acid levels were significantly higher in the loading group when compared with the titration group after 1 and 2 days following the initiation of treatment (p < 0.05). After 3 days of treatment there was a trend for the group that received the loading regimen to have slightly more improvement in YMRS scores compared with the titration group. Side-effects were minor for both treatments, however, a higher incidence of side-effects was reported in the titration group, with 50% of patients reporting sedation most likely because of increased use of benzodiazepines.

Conclusion:  This suggests that a loading dose of valproate is likely safe and may provide an earlier onset of antimanic effects in patients with bipolar disorder. Future studies with larger sample sizes are indicated.