Verification of using saliva as an alternative to serum for topiramate monitoring

Abstract

This study aims to verify the correlation between serum and saliva topiramate concentrations in Thai patients with epilepsy. Twenty-six subjects were patients aged 17 - 56 years old who were under treatment with topiramate. Their blood and saliva samples were collected before and 2 h after topiramate administration. Topiramate concentrations in serum and saliva samples were measured using turbidimetric immunoassay. Using the regression equation of y = 0.878x - 0.545 where x and y are topiramate concentrations in serum and saliva, respectively (r = 0.919, p < 0.001) based on the data previously reported, saliva topiramate concentrations of the 26 patients were used to calculate serum topiramate concentrations. Calculated serum topiramate concentrations were compared with the actual or measured serum topiramate concentrations using paired t-test. It was shown that there was no significant difference between the calculated and measured topiramate concentrations in serum of these patients. Results of the present study support the use of saliva as an alternative to serum for monitoring topiramate therapy.