Due to the lack of clinical pharmacists in the health system, plasma drug quantitation is used in Mexico to assess dosage titration, compliance, and toxicity during the treatment of patients with antiepileptic medications such as valproic acid (VPA). However, pharmacokinetic principles are not taken into account. To provide the necessary recommendations, this study investigated the intrapatient relationship between dosage and plasma VPA concentrations in different age groups, assessed the effect of co-medication that induces enzymes, and assessed the effectiveness of the monitoring procedure implemented in a pediatric hospital. A pediatric hospital in Hidalgo, Mexico, conducted this one-year retrospective observational study. In this retrospective investigation, VPA plasmatic concentration data were included from pediatric patients aged 1 to 15 years who had been conclusively diagnosed with epilepsy. The statistical analysis of the data was performed using Microsoft Excel®. A total of 260 patient files were examined. Serum levels were found to be constant in just 56.5% of the individuals. In 22% of patients, plasma VPA levels were found to be sub-therapeutic, and 15% had hazardous levels. Based on this study, children under the age of five years appear to be a diverse group for the factors studied. However, the change in plasma concentrations was not statistically significant (P < 0.05). We suggest that the optimum therapeutic outcome can only be assessed by tracking pharmacokinetic parameters for changes that occur in each patient, rather than merely using trial-and-error dosage because clinical pharmacists are not well-known in Mexico.
