Therapeutic drug monitoring
Also written as: TDM — Therapeutic drug monitoring
The practice of measuring antiseizure medication levels in blood to optimize dosing and minimize toxicity.
Full Definition
Therapeutic drug monitoring (TDM) in epilepsy involves measuring serum concentrations of antiseizure medications to guide dosing decisions. This practice is most commonly used with older medications like phenytoin, carbamazepine, and valproic acid, which have well-established therapeutic ranges. TDM is particularly valuable when assessing medication adherence, investigating breakthrough seizures, evaluating drug interactions, or managing toxicity. However, clinical response should always take precedence over laboratory values, as some patients may be well-controlled with levels outside the traditional therapeutic range.
Usage
Usage note: Less commonly used with newer antiseizure medications that have wider therapeutic windows.
In Context
- "Therapeutic drug monitoring revealed subtherapeutic phenytoin levels, explaining the breakthrough seizures." — Clinical assessment note
- "The patient's symptoms of ataxia prompted therapeutic drug monitoring, which showed toxic carbamazepine levels." — Emergency department report