Title 9. INDICATIONS FOR TDM. PROTOCOL FOR TDM.pdf ✅

PHARMD GURU Page 1 INDICATIONS FOR TDM: INDICATIONS WHERE TDM IS IMPORTANT: 1) Drug efficacy difficult to establish clinically (phenytoin). 2) Suspected toxicity. 3) Inadequate therapeutic response. 4) Compliance concerns 5) Dosage change 6) Change in patients clinical state 7) Change in co-medications (Quinidine decreases digoxin clearance) 8) Manifestations of toxicity and disease state are similar (Theophyllin). INDICATIONS FOR TDM EXAMPLE PURPOSE A. PHARMACOKINETIC CONSIDERATIONS: Drugs with narrow therapeutic range. Lithium, Digoxin, Phenytoin, Gentamicin, valproic acid. To avoid dose related toxicity. Drugs showing conc- dependent kinetics within therapeutic range. Phenytoin, Antibiotics. Subtle adjustment of dose. To check bioavailability. - To explain non attainments of therapeutic outcome (or) Unanticipated dose related toxicity following administration of standard dose of drug. B. PHARMACODYNAMIC CONSIDERATIONS: Drugs showing wide inter- individual variation in metabolism. Tri-cyclic anti depressants (20 to 30 fold difference in anti- arrhythmics) To maintain plasma concentration within acceptable, therapeutic range. INDICATIONS FOR TDM. PROTOCOL FOR TDM


PHARMD GURU Page 4 4. COLLECTION OF BIOLOGICAL SAMPLE:  Biological sample should be obtained in such a manner that, it permits significant analysis of the drug concentration in biological fluids.  Biological samples should be withdrawn after the drug reaches the steady state.  For most of the drugs (given without a loading dose) steady state concentration is raised at least after five biological half-lifes.  However, under certain conditions, TDM can be conducted prior to the attainment of steady state concentration. Ex: In case of suspected toxicity. 5. LABORATORY MEASUREMENT: SPECIFIC METHODS: 1) Colorimetry 2) UV-spectrometry 3) Fluorescence spectrometry 4) Chromatography a) Gas chromatography b) HPLC c) HPTLC d) SFC 5) Capillary electrophoresis. 6) Immunoassay: a) RIA b) Enzyme Immunoassay:  ELISA: Enzyme linked immunoassay.  EMIT: Enzyme multiplies immune-technique.  FPIA: Fluorescence polarization.  NIIA: Nephelometric inhibition. 7) LC-MS: Least count mass spectrometry. 6. STUDY PROTOCOL FOR TDM: 1) Title of the study / project 2) Investigators  Chief investigator.  Joint investigator.