Valproic Acid

Excreted Unchanged %
<5
Half-Life (Normalesrd) Hours
6-15/Unchanged
Plasma Protein Binding %
80-90
Volume Of Distribution L/Kg
0.19-0.23
Dose For Normal Renal Function
500 mg q24h for 1 wk
Second Dose
Second Dose: 500-1000 mg q24h
Adjustment For Renal Failure Method
D
Adjustment For Renal Failure Gfr, Ml/Min >50 [Recommended Level]
100% [D]
Adjustment For Renal Failure Gfr, Ml/Min 10-50 [Recommended Level]
100% [D]
Adjustment For Renal Failure Gfr, Ml/Min <10 [Recommended Level]
100% [D]
Supplement For Dialysis [Recommendation Level]: Ihd
IHD: Dose after dialysis, [D]
Supplement For Dialysis [Recommendation Level]: Pd
PD: Dose for GFR <10, [B]
Supplement For Dialysis [Recommendation Level]: Crrt
CRRT: None, [D]
References
Koch-Weser J, Browne TR. Drug therapy: Valproic acid. N Engl J Med. 1980; 302: 661-6.[PMID: 6766529] / Kane SL, Constantiner M, Staubus AE, Meinecke CD, Sedor JR. High-flux hemodialysis without hemoperfusion is effective in acute valproic acid overdose. Ann Pharmacother. 2000; 34: 1146-51. [PMID: 11054983] / Sztajnkrycer MD. Valproic acid toxicity: overview and management. J Toxicol Clin Toxicol. 2002; 40: 789-801. [PMID: 12475192] / Zaccara G, Messori A, Moroni F. Clinical pharmacokinetics of valproic acid&#151; 1988. Clin Pharmacokinet. 1988; 15: 367-89. [PMID: 3149565]
Toxicity Notes
Hepatic failure. Pancreatitis. Protein binding decreased in uremia. Because binding is concentration dependent, more free drug at high levels. Dialysis and CRRT may be effective for overdose.