Comparison of Serum Total Valproic Acid Levels and %CDT Values in Chronic Alcohol Addictive Patients in an Italian Clinic: A Retrospective Study

Background

Valproate is a broad-spectrum anticonvulsant that is effective in the treatment of tonic-clonic, myoclonic and absence seizures as well as in partial seizures as a second-line drug. It has been widely demonstrated in the literature that the effect of valproate on type-A γ-aminobutyric acid (GABA-A) receptors may reduce relapse to ethanol abuse. This retrospective study evaluated a 3-year period in which 42 patients from the Department of Alcoholism and Substance Abuse (DASA) were treated with valproate.

Objectives

We compared different serum total valproic acid (VPA) concentrations, and the effectiveness of this drug in maintaining alcohol abstinence was evaluated by percentage of carbohydrate deficient transferrin (%CDT) values.

Method

CDT is a biochemical marker used for identifying regular high alcohol consumption and monitoring abstinence in outpatients during treatment. Serum concentrations of valproate were divided into four groups: <10, 10–30, 31–50, and >50 µg/mL.

Results

This study shows that a mean serum total VPA concentration >30 µg/mL is more effective in maintaining alcohol abstinence than a lower one (p < 0.05). In this study, mean serum total VPA concentrations between 31 and 50 µg/mL showed the same effectiveness as higher ones (>50 µg/mL); in fact, there was no significant difference in mean %CDT values between these two groups (p > 0.05). After at least 12 months’ treatment with valproate, mean platelet counts increased by 12 × 10³/μL compared with baseline (254 ± 63 vs 242 × 10³/μL, p > 0.05, respectively) in patients with mean serum total VPA levels <10 μg/mL; increased by 8 × 10³/μL from baseline (253 ± 59 vs 245 × 10³/μL, p > 0.05, respectively) in patients with levels between 10 and 30 μg/mL; decreased by 2 × 10³/μL from baseline (265 ± 63 vs 267 × 10³/μL, p > 0.05, respectively) in patients with levels between 31 and 50 μg/mL, and decreased by 48 × 10³/μL from baseline (215 ± 56 vs 263 × 10³/μL, p < 0.05, respectively) in patients with levels >50 μg/mL.

Conclusion

A mean serum total concentration lower than the currently accepted therapeutic level (50–100 µg/mL) may have the same effectiveness in maintaining alcohol abstinence with a lower risk of presenting side effects.