Serum monitoring of carbamazepine in patients with epilepsy and clinical implications

Abstract

Carbamazepine is a drug with a narrow therapeutic range that requires clinical monitoring, since its toxic effects are not easily predictable, and the therapeutic level can vary. Our study aimed to monitor the serum level and determine the concentration/dose relationship of carbamazepine in people with epilepsy, analyzing its clinical implication. It is observed that 90.48% of the study volunteers present serum level values (4.3–10.4 mg/L) within the therapeutic range (4–12 mg/L); 7.14% present supratherapeutic levels (12.7–14.4 mg/L), 2.38% subtherapeutic (0.93 mg/L). The findings indicate a negative correlation (r = -0.616; r2 = 0.379; p = 0.001), between the dose (mg/day) and the dose ratio (mg/L/mg/day); and a positive correlation (r = 0.544; r2 = 0.296; p = 0.002), between the dose (mg/day)-serum concentration (mg/L). ANOVA and Tukey’s test mean difference is significant (p<0.05). It is concluded that there is a positive and significant linear correlation between daily doses and serum carbamazepine concentrations, which should be considered to individualize the dose and optimize clinical results.

Serum concentrations of valproic acid in people with epilepsy: Clinical implication

“…The value of the Mann-Whitney U Test for the median serum concentrations (p = 0.952 α>0.05) was not different between the male and female sex groups. In this investigation, the patients voluntarily donated a single blood sample after three months of treatment, the purpose of which was for the drugs to reach the concentration in the steady state (Css); and the time of extraction was carried out at a minimum concentration (Alvarado et al, 2020;Alvarado et al, 2022a;Alvarado et al, 2022b;Guk et al, 2019;Hernández-Jerónimo et al, 2022). In a previous study carried out by Cotuá et al (2017), it is indicated that the blood sample is taken before the morning dose of the drug, whose serum concentration obtained is called the minimum, basal, trough or pre-dose concentration.…”

“…Descriptive, cross-sectional, and prospective recruitment for convenience and non-randomized study (Alvarado et al, 2021a;Alvarado et al, 2022a;Bonalde et al, 2021).…”

“…A single blood sample was collected from each volunteer who attended for control and as part of normal medical practice (Alvarado et al, 2022b). The extrac-tion of the blood sample was carried out in the morning before the VPA dose (Minimum concentration); 3 mL of venous blood was collected in Vacutainer tubes, BD Bioscience previously coded (Alvarado et al, 2022a;Alvarado et al, 2022b;Guk et al, 2019;Hernández-Jerónimo et al, 2022).…”

“…The patients who attended the medical control were informed of the objectives and importance of the study, and all those who agreed to participate in the study met the following selection criteria: patients receiving monotherapy with valproic acid (1500-2000 mg/day) or in combination AVP with carbamazepine (CBZ) and AVP plus phenytoin (PHT); with no less than three months of treatment, comply with the dose and frequency of administration of anti-epileptics, and not self-medicate (Alvarado et al, 2019;Alvarado et al, 2022a;Alvarado et al, 2022b).…”

“…Epilepsy is a chronic neurological disorder prevalent in developing countries, including Latin America, whose treatment must be through precision medicine, which is based on ethnicity, genotype/phenotype profile, and therapeutic drug monitoring, whose purpose is to maintain serum concentrations within the therapeutic index, minimizing adverse reactions and optimizing pharmacological therapy (Alvarado et al, 2018;Alvarado et al, 2022a;Alvarado et al, 2022b). Various anti-epileptic drugs (AEDs) are used in the treatment of this disease, including valproic acid (VPA).…”