Concentration of antiepileptic drugs in persons with epilepsy: a comparative study in serum and saliva

Aim of the study: The monitoring of antiepileptic drugs (AEDs) in clinical setting is important for measuring the efficacy of drugs and their safety and in personalizing drug therapy. We investigated the levels of AED, carbamazepine (CBZ), phenytoin (PHT) and phenobarbital (PHB), to understand their association in saliva compared with those in serum during the therapy. Materials and methods: In this study, we performed a prospective study of 116 persons with epilepsy (PWE; mean age 26.90 +/- 11.83 years). Serum and saliva samples were collected at trough levels from the patients, who were under the treatment of CBZ, PHT and PHB either alone or in combination of these drugs for at least three months. The drug levels were assessed by high-performance liquid chromatography. Results and conclusions: The number of males (n = 88; 75.86%) was higher than females (n = 28; 24.14%) among the recruited patients. The intake of CBZ, PHT and PHB was observed in 49.14%, 68.10% and 38.79% of PWE, respectively. The levels of these AEDs showed a significant correlation (p < 0.05) between serum and saliva. Interestingly, the levels of mono-therapy or bi-therapy showed a significant association (p < 0.05) between serum and saliva, however, there was no significant association in case of poly-therapy. This is the first report in the Indian population on simultaneous estimation of the three commonly used AEDs, such as CBZ, PHT and PHB in serum and saliva implicating their associations, either in mono-therapy or bi-therapy in PWE.