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.