Therapeutic Drug Monitoring
THERAPEUTIC DRUG MONITORING (TDM):
- Refers to individualization of drug dosage by maintaining plasma or blood drug concentrations within targeted therapeutic range or window.
Principle:
- Based on a drug’s close relationship between plasma drug level & it’s clinical effect.
THERAPEUTIC WINDOW:
- Is the minimum dosage necessary for a patient to benefit from the main effects intended of a specific drug.
- TDM measures drug concentrations & clinically interprets its effects.
- Mainly, individualizing therapeutic regimens for optimal patient benefits.
DRUG PRE-REQUISITES:
TDM testing is performed for drugs with certain qualities:
- For drugs with lower therapeutic index.
- Eg: Digitalis, aminoglycosides, gentamycin, TCA’s, theophylline, Lithium, anti-epileptics, Immunomodulators & antiarrhythmics.
- For drugs with wider variations in pharmacokinetics.
- For drugs with known correlation between serum concentration & drug response or toxicity.
TDM UNAPPLICABLE DRUG GROUPS:
- Not used for drugs whose effect are easily measured.
- Eg: Anti-hypertensives – Via BP monitoring
- Anti-coagulants (Warfarin) – Bleeding time monitoring.
- Anti-Diabetics – Metformin
- Not used for drugs producing active metabolites (activated inside body).
Exam Important
THERAPEUTIC DRUG MONITORING
THERAPEUTIC WINDOW:
- Is the minimum dosage necessary for a patient to benefit from the main effects intended of a specific drug.
TDM testing is performed for drugs with lower therapeutic index.
- Eg: Digitalis, aminoglycosides, Gentamycin, TCA’s, theophylline, Lithium, anti-epileptics, Immunomodulators & antiarrhythmics.
TDM testing is not performed for whose drugs whose effect are easily measured.
- Eg: Anti-hypertensives – Via BP monitoring.
- Anti-coagulants (Warfarin) – Bleeding time monitoring.
- Anti-Diabetics – Metformin.
Don’t Forget to Solve all the previous Year Question asked on Therapeutic Drug Monitoring
