OPTIMIZATION AND ASSESSMENT OF TDM AT TERTIARY CARE: AN INDIVIDUALIZATION PROCESS

Abstract

Epilepsy is a chronic disease that may require antiepileptic drug (AED) therapy. TDM is a process which starts from taking the sample from the patient till its interpretation of results. A single quantifiable value of drug level in a patient makes the dosage regimen in chronic therapies when narrow therapeutic drugs are used. It is the goal of TDM to use drug concentration to manage a patient’s medication regimen and optimize outcome. Clinicians routinely monitor pharmacodynamics by directly measuring physiological indices of therapeutic responses e.g. lipid concentrations, blood glucose, blood pressure, clotting tests. For many drugs there is either no readily available measure of effect or it is insufficiently sensitive. It is an integral part of pharmacotherapy which starts from the decision to request a drug level in a biological sample in a clinical laboratory and is followed by clinical interpretation for the validity of therapeutic management. Commonly used conventional antiepileptic drugs are Phenytoin, Carbamazepine, Valproic acid, Phenobarbitone. These drugs have complex pharmacokinetic properties leading to fluctuate their serum concentration in the systemic compartment at a given therapeutic dose. The present study was done along with the lithium to integrate their therapeutic, subtherapeutic and toxic concentratinos retrospectively. 855 levels of blood samples were tested, 76 were inconclusive comprising of 8.9%. Out of total 275 lithium samples 80% were in the therapeutic range of 0.3 to 1.2 mEq/Litre. 250 samples of Phenytoin were assessed and 41.20% had therapeutic level. 106 samples of Carbamezepine had a varied percentage of sub-therapeutic, therapeutic and toxic levels. Only 3.77% of levels were above 12 micrgram/ml and 16.03% levels were inconclusive. Out of 151 levels of Valproic acid 50.98% levels fall between 70-90 microgram/ml. Although phenobartritone is not prescribed commonly only 73 samples were assessed and 47.94% comprised in the therapeutic range of 10-20 microgram/ml.