Salivary free concentrations of anti-epileptic drugs: an evaluation in a routine clinical setting.
OBJECTIVE
This study was aimed at correlating the salivary and serum free concentrations of anti-epileptic drugs (carbamazepine, phenytoin and sodium valproate) in a population of neurological patients in a routine clinical setting.


METHODS
Twenty-seven paired serum/saliva specimens from 22 patients: 10 for carbamazepine, 8 for phenytoin and 9 for sodium valproate were obtained to study these correlations. Salivary and serum free concentrations of anti-epileptic drugs, anti-epileptic drug dosing history, and associated information were collected prospectively. The salivary and serum free concentrations of the anti-epileptic drugs were simultaneously quantified using fluorescence polarization immunoassay (TDx analyzer).


RESULTS
For both carbamazepine and phenytoin there was a strong correlation between the salivary and serum free concentrations, 0.99 and 0.98, respectively. The mean ratio of salivary to serum free carbamazepine concentration was 1.02 +/- 0.11 and 0.82 +/- 0.15 for phenytoin. A poor correlation between salivary and serum free concentration was observed for sodium valproate (0.70) with a mean ratio of salivary to serum free concentration of 0.48 +/- 0.27.


CONCLUSIONS
Monitoring of free salivary concentrations of anti-epileptic drugs, particularly phenytoin and carbamazepine proved to be a realistic alternative in this routine clinical setting.
al Za'abi
Mohammed
M
Department of Clinical Pharmacology & Therapeutics, Sultan Qaboos University Hospital, P.O. Box 35, Al-Khod, Muscat-123, Sultanate of Oman.
Deleu
Dirk
D
Batchelor
Chris
C
D000293:Adolescent; D000328:Adult; D000368:Aged; D000554:Ambulatory Care Facilities / Q000706:statistics & numerical data; D000927:Anticonvulsants / Q000097:blood / Q000378:metabolism*; D016903:Drug Monitoring / Q000379:methods; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000097:blood / Q000188:drug therapy / Q000378:metabolism; D011446:Prospective Studies; D012463:Saliva / Q000378:metabolism*
D000927:Anticonvulsants