title: Conversion from delayed-release sodium valproate to extended-release sodium valproate: initial results and long-term follow-up.
abstract: OBJECTIVE
  The goal of our study was to evaluate clinical and serum valproic acid concentration changes in patients following overnight conversion from delayed-release sodium valproate (VPA-DR) to the same daily dosage of extended-release sodium valproate (VPA-ER).
  
  
  METHODS
  Epilepsy patients on VPA-DR were offered the chance to convert to VPA-ER. Thirty patients were converted to twice-daily dosing and 11 were converted to once-daily dosing. Trough levels of valproic acid were measured prior to the change and 2 weeks after conversion. Short-term and long-term clinical data were evaluated.
  
  
  RESULTS
  Patients successfully converted from VPA DR to VPA-ER. No significant difference in percentage change in serum trough valproic acid level was observed when comparing dosing frequency of VPA-DR, total daily dosage of VPA, conversion to once-daily versus twice-daily VPA-ER, or presence of enzyme-inducing agents. Mean seizure count per month prior to conversion was 3.35 versus 3.29 following conversion. Improvements in tremor, weight gain, and nausea/vomiting were noted.
  
  
  CONCLUSIONS
  Overnight conversion to VPA-ER was well tolerated by all patients. Long-term results were favorable, with 77.5% of patients remaining on drug. Seizure counts and adverse events remained the same or were improved in both short-term and long-term evaluations. Dosing of VPA-ER either once-daily or twice-daily is acceptable.
authors: Penn State Milton S. Hershey Medical Center, 500 University Drive, Hershey, PA 17033, USA. pmccabe@psu.edu
authors: Paul H
authors: PH
authors: McCabe
authors: Nancy C
authors: NC
authors: Michel
authors: Cathy D
authors: CD
authors: McNew
authors: Erik B
authors: EB
authors: Lehman