[Valproic acid and protein supplements: possible clinically relevant drug interaction]

Area of Science:

• Pharmacology
• Clinical Pharmacy
• Drug Interactions

Background:

• Valproic acid (VPA) is a critical medication with a narrow therapeutic index (50-100 µg/mL).
• High pharmacokinetic variability in VPA is often linked to plasma protein binding unsaturation (PPBU).

Purpose of the Study:

• To investigate a potential interaction between valproic acid and protein supplements.
• To understand how protein supplement administration affects VPA plasma concentrations.

Main Methods:

• A case report detailing a 60-year-old patient undergoing VPA treatment.
• Analysis of plasma VPA concentrations before and after administration with a protein supplement.
• Monitoring VPA levels after adjusting the timing of VPA and protein supplement intake.

Main Results:

• A notable decrease in plasma VPA concentrations was observed when co-administered with a protein supplement.
• Separating the intake of VPA and protein supplements led to VPA serum concentrations returning to the therapeutic range.

Conclusions:

• Protein supplements may interact with valproic acid, potentially affecting its therapeutic efficacy.
• Timing VPA and protein supplement administration separately is crucial for minimizing fluctuations in plasma VPA levels.