Therapeutic Drug Monitoring (TDM) involves analyzing drug concentrations in blood to ensure medication doses remain within a therapeutic range to be effective while avoiding toxicity. TDM is important for drugs with a narrow therapeutic index, where small changes in dose can cause harm, and when patient factors like kidney or liver disease may impact drug levels. TDM guides dosage adjustments and is used to monitor patient compliance, detect drug interactions, and diagnose suspected overdose or toxicity. The goal of TDM is to individualize drug therapy for each patient based on their circulating drug concentrations.

1. THERAPEUTIC DRUG
MONITORING
By-
Dipesh Adesh Gamare
Final Year B. Pharmacy
Roll no. 934

2. Therapeutic Drug Monitoring
Therapeutic Drug Monitoring (TDM) involves the analysis,
assessment, and evaluation of circulating concentrations of drugs in
serum, plasma, or whole blood.
Purpose of therapeutic drug monitoring is to ensure the medication dose is
at therapeutic range and not in toxic range

3. a
 At appropriate time interval of drug administration, there is a need to
estimate the patient's plasma drug concentration.
 Adequate information should be known on the pharmacological and
pharmacokinetic profiles of the administered drugs
 There should be adequate and relevant information on the patient's
profile such as demographic data, laboratory, clinical status and other
clinical evidence.
 There is needed to interpret the plasma drug concentration for the
individualization of drug regimen according to need of patients.
BASIC PRINCIPLES OF THERAPEUTIC DRUG MONITORING

4.  Prevention of ineffectiveness and toxic effects it is important to monitor the drug that
has narrow therapeutic range.
 Optimization of dosage according to therapeutic response seen patients.
 There is importance of therapeutic drug monitoring for the drugs such as theophylline
which shows abrupt dose response curve.
 Therapeutic drug monitoring is also important to detect the changes in pharmacokinetic
parameters of drugs in certain patients due to disease or any influence condition.
 Monitor the patient compliance but the major limitation is that it is costly and generally
used in clinical trials only.
 Useful for those drugs whose therapeutic effects cannot be readily assessed by clinical
observation.
 Therapeutic drug monitoring indicating to established relationship between
concentration of drugs in plasma and its therapeutic or toxic effects.
OBJECTIVES AND SIGNIFICANCE/INDICATIONS OF THERAPEUTIC DRUG
MONITORING

5.  Therapeutic drug monitoring is important for those drugs which follow non-linear
kinetics.
 Therapeutic drug monitoring is important to investigate unexpected lack of efficacy.
 TDM is indicated in renal disease: There is alteration in plasma concentration of drug as
alter in the dose of drug. This relationship is affected by the renal disease. In which high
plasma concentration is associated with renal impairment which leads to toxicity even in
small increased in the dose of drug. It is mostly seen with the drug which has narrow
therapeutic index such as in case of digoxin, lithium and aminoglycoside antibiotics.
Drug interactions- For example, administration of thiazide increases the plasma
concentration of lithium.
Diagnosis of suspected toxicity and decides for the case of drug abuse.
TDM is also used in guiding purpose for withdrawal of drug therapy.

6.  There is indication of TDM if the consequences of overdosing and underdosing are
serious.
 TDM is indicated if there is a small difference between a therapeutic and toxic dose
range.
 TDM is indicated if there a certain change in the physiologic state of patient that may
unpredictably influence the circulating drug concentrations.
 TDM is indicated because of drug interaction such cases where the patient is on more
than two drugs.
 There is need of TDM to establish therapeutic regimen in several physiological
conditions like pregnancy, neonate, children, elderly and pathological conditions such as
renal disease hepatic disease, etc.
 There is need of TDM when unexpected lack of efficacy or toxicity.
 TOM helps in monitoring patent compliance.
NEED OF THERAPEUTIC DRUG MONITORING

7.  TDM is unnecessary performed for wide therapeutic range drug.
 TDM is also unnecessarily or no need to perform for those drugs
whose pharmacological effects can be clinically quantified.
 It is not applicable for those drugs who follows linear kinetic.
 Clinical outcome cannot be correlated to either dose or plasma
concentration for certain drugs.
Limitations of Therapeutic Drug Monitoring

8. 1) Collection of Patient Data
2) Statement of Therapeutic Goals
3) Selection of Drug Therapy
4) Establishment of Monitoring Parameters
5) Identification and Confirmation of Problems
6) Communication of Findings
FACTORS AFFECTING THE THERAPEUTIC DRUG MONITORING

9. 1. Monitoring of certain drugs theophylline, valproic acid, methotrexate is associated
with the increased efficacy and decreased incidences and side effects.
2. Monitoring determines the safety of the dosage regimen.
3. Appropriate interpretation of drug concentration measurements is used in the
monitoring for dosage adjustment that minimizes the proportion of patient with serum
concentration outside the therapeutic range.
4. Monitoring encourages professional interactions between members of the health teams
such as physician and pharmacist.
5. It provides an opportunity for clinical pharmacist to excel in therapeutic challenges
and to work as a vital segment of health team in the area of pharmacotherapeutics.
6. It provides additional input in pharmacotherapy.
APPLICATIONS OF THERAPEUTIC DRUG MONITORING: