Title: Correlation of serum level of carbamazepine with seizure control and adverse drug reactions among epileptics in Ibadan, Nigeria.
Background: Epilepsy is a chronic neurological disorder requiring long-term treatment. Seizure control requires adequate blood levels of anti-seizure drugs. Carbarmazepine is one of the most prescribed antiepileptic drugs in Nigeria. This study was carried out to investigate the correlation between serum levels of carbamazepine and seizure control and adverse drug reactions among epileptics in Ibadan, Nigeria.
Methods: In a cross-sectional study, sixty-nine patients with confirmed diagnosis of epilepsy who had been on treatment with carbamazepine alone or in combination with phenytoin for at least one month were enrolled into the study and divided into two groups based on seizure control. Drug level in pre-dose (steady state) venous blood was analyzed using high performance liquid chromatography.
Result: The mean serum concentration of carbamazepine (CBZ) and carbamazepine-epoxide (CBZ-EP) was 13.5±9.3ìg/mL and 6.34±12.61ìg/mL respectively. Patients with good seizure control had mean serum CBZ concentration of 12.7 ± 9.2ìg/mL versus 15.02 ± 9.7ìg/mL among patients with poor seizure control (P=0.33). The serum concentration of CBZ-EP in patients with good seizure control was 8.05 ± 15.2ìg/mL while it was 3.11 ± 3.5ìg/mL in the second group (P=0.122). Drowsiness was the commonest adverse drug reaction (26.1%) and it did not necessitate withdrawal of the drug. Conclusion The study showed that serum level of carbamazepine does not correlate with seizure control and adverse drug reactions.