Therapeutic level monitoring of anti-epileptic drugs

Therapeutic level monitoring of anti epileptic drugs

1. Therapeutic Drug Monitoring of Antiepileptic Drugs-I

2. Individualization of treatment Variability is the law of life, and as no two faces are the same, so no two bodies are alike, and no two individuals react alike and behave alike under abnormal conditions which we know as disease. Sir William Osler

3. Early era of antiepileptic drugs Potassium bromide Fixed dose combination: 100mg + 300mg

4. The reference range Lower limit: below which a therapeutic response is relatively unlikely to occur Upper limit: upper limit above which toxicity is relatively likely to occur The reference range is not a therapeutic range

5. Problems Plasma concentrations of drugs correlate much better than dose with the clinical effects There is substantial pharmacokinetic variability and thus large differences in dosage are required in different patients There is no laboratory markers of clinical efficacy or toxicity

6. I t is important to treat the patient and not the blood concentration.

7. I ndividual therapeutic concentration The concentration, or range of concentrations, which has been empirically found to be associated with an optimum response in an individual patient . It provides a useful reference value for informing management decisions should a modification in the clinical status of a patient occur over time .

8. Indications for therapeutic monitoring At treatment onset when target dose is reached Suspected toxicity Poor seizure control after long term abstinence Pregnancy Change of formulation Suspected drug interaction or altered metabolism

9. What and how to measure? Trough level Serum concentration Salivary level Unbound drug concentration

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