Therapeutic drug monitoring- Descriptive questions and answers and mcqs

1. 1) What is Therapeutic drug monitoring (TDM) ?
Ans : Therapeutic drug monitoring (TDM) refers to the measurement of drug
concentrations in biological fluids with the purpose of optimizing a patient’s drug
therapy. During administration of a dosage regimen, concentration should be
maintained within the therapeutic window. TDM is an important tool utilized to
individualize dosage regimen by maintaining plasma or blood drug concentrations
within the therapeutic range.
2) What is need for therapeutic drug monitoring?
Ans :
TDM can be an important tool in selected situations. Some criteria of drug in TDM
are given below :
• Drug with narrow therapeutic index.
• Drug should exhibit non-linear pharmacokinetics.
• Should have a beneficial concentration response relationship between the blood
drug conc. and pharmacological effects with respect to both efficacy and toxicity.
• There should be no easily measurable physiological parameter.
TDM is used in two major situations
• To assist the optimization of drug therapy, including minimizing the risk of drug
toxicity.
•To identify a drug or substance this may be contributing to the presentation of a
medical emergency.
There are some common clinical situations where therapeutic monitoring of drugs
may be useful to confirm adequate serum concentrations where clinical response is
inadequate
 TDM can be used to assess the appropriateness of dosing regimen to maintain the
minimum concentration required to exhibit efficacy

2.  To avoid drug toxicity: maintaining a drug within the therapeutic range can help
to minimize the risk of toxicity
 To individualize dosing of some drug with an unpredictable dose-response curve
 To assess medication compliance
 To help predict a patient’s dose requirements.
 To minimize the time period needed for dosage adjustment.
 To identify poisons and to assess the severity of poisoning on an emergency basis
in a poisoned patient.
 To assist dose adjustment in various disease states where individual variations in
drug ADME is important.
3) What factors to be considered during the therapeutic drug monitoring?
Ans :
A number of factors may affect serum drug concentrations and need to be
considered when interpreting TDM results. Some of the factors explain below :
 Patient demography: The patient’s age, sex, body weight and ethnicity should be
considered when interpreting TDM results.
 Dosage regimen and duration of therapy: For a drug, sufficient time should
elapse to allow steady-state to be achieved before TDM is performed. If a loading
dose has not been given, this means at least 5 half-lives of the drug should elapse.
 Sampling time: The serum concentration of a drug depends on the time when the
blood drawn for a TDM assay was sampled in relation to the last dose.
 Patient compliance: If the concentration of the drug is lower than expected, The
possibility of non-compliance should be considered before a dose increase.
 Individual capacity to distribute/ metabolise / excrete the drug: Patients with
renal impairment have a reduced ability to excrete renally cleared drugs, and the
interpretation of TDM for renally- cleared drugs such as digoxin and

3. aminoglycosides should always be made in the context of the patient’s renal
function.
 Altered protein binding: Conditions such as malnutrition or nephropathy may
reduce the concentration of plasma protein. The strongly plasma protein bound
drugs such as phenytoin, a reduced albumin level may result in higher
concentration of unbound (free) drug. The measurement of both total drug
concentration and free drug concentration can be useful in that situation.
 Drug interaction: TDM results should be interpreted in the light of the patient’s
concomitant drug therapy. Example digoxin toxicity with drug amiodarone,
quinidineor verapamil.
 Pathological factors: The patient’s co-morbidites should be taken into
consideration when interpreting TDM result.
 Alcohol and tobacco use: Chronic use of alcohol increased clearance and
decreased serum concentrations of hepatic cleared drugs such as phenytoin
Cigarette smoking increases the hepatic clearances of theophylline.
 Medication and sampling errors: If TDM result is incompatible with drug
administration records, the possibility of a medication or sampling error should be
considered.
 Laboratory errors: In a laboratory error is suspected, the laboratory should be
contacted and asked to repeat the assay
4) What is Indian scenario for therapeutic drug monitoring?
Ans :
In India TDM is available in following two ways
Clinical pharmacological departments in large teaching hospitals
Generally HPLC is used in teaching hospital
Instrument available locally

4. Cost effective for many patients
Private medical laboratories
Private laboratories are use automated equipment and imported ready-to-use kits.
More expensive.
It does not provide clinical interpretation of results.
The final results are providing a therapeutic drug measuring service rather than
therapeutic drug monitoring There are a number of factors which influences the
use of TDM in India. Cost: The widespread availability of TDM in India will need
strong economic justifications but it’s quite expensive for India.
Alternative medical systems: Pharmacokinetic and pharmacodynamic interactions
between various drugs which difficult to assess the outcome of drug therapy and
the result of TDM assay.
Malnutrition: Nutritional deficiencies are common and may affect drug
pharmacokinetics Ethnic differences: Advanced research is needed to characterize
possible variations in therapeutic ranges in various Indian subpopulations.
Variations in bio-availability: Differences in formulation between brands of the
same drug may results in variations in bioavailability.
• Examples of drugs indicated for TDM
• Bronchodilators: Theophylline • Antibiotics: Aminoglycosides - Gentamicin,
Amikacin , Vancomycin
• Immunosuppressants: Cyclosporine
• Anticancers: Methotrexate
• Antiepileptics: Phenobarbital, Phenytoin, Valproate
• Cardiac Drugs: Digoxin, Procainamide, Lidocaine
• Psychoactive Drugs: Lithium.

5. 5) Limitations of Therapeutic Drug Monitoring?
Ans :
 Cost of TDM study
 Only broad therapeutic range drugs are benefitted
 insufficient or invalid data for suggesting target concentration range
 laboratory to laboratory variations in reports
 Active metabolite(s) of the drug may contribute to the therapeutic
effect, but the metabolite cannot be measured
 Variation or lack of accuracy and sensitivity of the drug assay
methods
 Data on serum concentration is not required for the drug with broad
therapeutic range.
 For certain drug, the value of serum concentration are less justifiable.
6) Applications of Therapeutic Drug Monitoring?
Ans :
• To determine safety of drugs.
• 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.
• To encourage professional interactions between members of the health teams
such as physician and pharmacist.
• To provide opportunity for clinical pharmacist to excel in therapeutic
challenge.
• To maximize the efficacy and minimize the side effects or toxicity.
• To improve clinical pharmacokinetics and to work as a vital segment of
health team in the area of pharmacotherapeutics.
• To establish relationship between concentration of drug in plasma and its
therapeutic or toxic effect.

6. • It provides additional input in pharmacotherapy.
Descriptive:
1. Define TDM
2.Give two uses of TDM.
3.Give any two factors to be considered during TDM.
4. What is the need of TDM?
5. Discuss the Indian scenario for TDM.
6. Write an illustrative note on TDM.
7.Discuss the factors to be considered during TDM.
8. Explain in detail factors affecting TDM
9. Define Drug Monitoring
10. What is the basic principle of TDM
11. What is the role of Pharmacist in health care delivery systems.
12. What are Limitations of TDM
13. Write the applications of TDM.
1) Write in details about Therapeutic Drug Monitoring.
2) what is Therapeutic Drug Monitoring and explains its objectives .
3) Explain the factors affecting Therapeutic Drug Monitoring.
4) Explain the factors to be considered during Therapeutic Drug Monitoring.
5) Explain the TDM and it's needs.
6) explains the objectives and limitations of TDM.

7. 7)Explain the objectives, needs and limitations of Therapeutic Drug Monitoring.
8)Define Therapeutic Drug Monitoring. enlist the factors affecting the TDM and
explain any four .
9) Give the applications of Therapeutic Drug Monitoring .
10) Discuss the Indian scenario of TDM.
MCQ’S on TDM
1) The basic principle of Therapeutic Drug Monitoring is to measure _________.
a) Patient's blood drug concentration b) Limited role in
drug toxicology
c) Patient urine drug concentration d) None of the above
2)_________ drug having a narrow therapeutic window in Therapeutic drug
monitoring .
a) Methotrexate b) Phenytoin
c) Theophylline d) All of the above
3) _______drug required for cardiovascular diseases in Therapeutic Drug
Monitoring .

8. a)Gentamycin b) Amikacin
c) Digoxin d) Tobramycin
4) _______drug shows steep dose response curve in TDM .
a) Lithium b) Phenytoin
c)Digoxin d) Theophylline
5) Therapeutic drug monitoring is used when
a) Pharmacological effect can be quantified
b) Therapeutic efficacy is difficult to access
c) Drugs with narrow therapeutic index
d) Both b and c
6) Therapeutic drug monitoring process consists of ______.
a) Decision to request drug level b) Biological sample
c) Laboratory measurement d) All of the above
7) The time required for the serum concetration of a drug to decrease by 50% is
called
a) Volume of distribution. b) Area under curve
c) Half-life d) Minimum effective
concentration
8) In earlier days TDM services began with _______ instrument .
a) HPLC b) GSC
c) HPTLC d) Column Chromatography
9) With the therapeutic drug monitoring patient benefits _______.
a) Medically b) Economical

9. c) Both a and b d) None of these
10) Multiple drug therapy _______ the probability of drug induced disease.
a) Increase b) Decreases
c) Does not affects d) None of these
11) A brach of clinical pharmacy / pharmacology that deals with measurement of
medication concentration in the blood , mainly drugs with narrow therapeutic
range is called as
a) Pharmacovigilance b) Pharmacotherapeutics
c) Therapeutic Drug Monitoring c) Pharmacoginomics
12) TDM commonly used to help clinicians monitor and maintain drug level
within :
a) Therapeutic window b) Below MEC(minimum
effective concentration)
c) Above MTC(Minimum Toxic Concentration). d) Both b & c
13) Therapeutic Index must be _______ for a drug to be usable:
a) >1 b) <1
c)=1 d) 0
14) Why we need TDM ?
a) Patient with impaired clearance of drug b) In-adequate therapeutic
response
c) Drugs whose efficacy is difficult to establish d) All of these
15) Minimum data requirements of TDM :
a) Dose regimen. b) Date nd Time last dose given /
Taken
c) Information on sample d) All of the above

10. 16) Loading dose is determined by
a) Bioavailability b) Volume of Distribution
c) Half - life d) Clearance
17) Maintenance dose is determined by
a) Bioavailability b) Volume of distribution
c) Half - life d) Clearance
18) Therapeutic Drug Monitoring is useful in drugs :
a) With wide therapeutic index b)With high protein binding
c) Which are not liable to interact d) In which metabolite is inactive
19) In India, the therapeutic drug monitoring was introduced in _________.
a) 1986 b) 1985
c) 1980 d) 1990
20) The Therapeutic Drug Monitoring is available for
a) Inpatient b) Outpatient
c) Both a & b d) None of the above
21) Describes the dosage range between the minimum effective therapeutic
concentration or dose, and the minimum toxic concentration or dose:
a)Therapeutic window b) ED 50
c) LD50 d) Margin of safety
22) Difference between usual effective dose and dose causing life threatening
effects is called:
a)Margin of safety b) Dosing interval
c) Dodge regimen d) Fraction of dose

11. 23) This new responsibility of pharmacists is to actively ensure that prescribed
drug therapy is_________.
a) Effective b)Safe
c) Economical d)All
24) With the therapeutic drug monitoring patient benefits_________.
a) Medically b) Economically
c) Both (a) and (b) d) None of these
25) Adverse reactions of drugs are a major public health problem and account
for___% of
admissions to hospital medical services.
a) 10-20 b) 3-5
c) 6-8 d) None of these
26) It has been stated in the different studies that with more careful prescribing and
monitoring_____ % of these adverse reactions could be prevented.
a) 20-230 b) 40-50
C) 60-80 d) None of these
27) Hospitalized patients receive an average of __________ drugs.
a) 2-3 b) 8-10
c)5-6 d) None of these
28) Nursing home patients receive an average of________ medications.
a) 5-9 b) 1-3
c) 10-13 d) None of these

12. 29) Multiple drug therapy________ the probability of drug induced disease.
a) Increases b) Decreases
c) Does not affect d) None of these
30) Unit dose drug distribution systems have significantly reduced the occurrence
of_____.
a) ADR's b) Side effects
c) Medication errors d) None of these
31) _______is necessary for the pharmacist to assess the therapy.
a) Skill b) Knowledge
c) Proper Training d) positive attitude.
31) A monitoring plan usually consists of a combination of______parameters.
a) Objective b) Subjective
c) Both (a) and (b) d) None of These
32) For a problem involving drug administration,_______may be the professional
who can
best solve the problem.
a) Physician b) Nurse
c) Pharmacist d) None of These
33) Monitoring determines the_______ of the dosage regimen.
a) Quality b) Efficacy
c) Safety d) None of These
34) Pharm-D course is a ____ year doctoral course.
a)6 b)4

13. c) 3 d) None of These
35) The basic principle of TDM is to measure
a. Patient's blood drug concentration.
b. Limited role in drug toxicology.
c. Patient's urine drug concentration
d. None of above.
36) TDM process consists of
a. Decision to request drug level.
b. biological sample.
c. Laboratory measurement
d. All of the above.
Multiple Choice Questions:
1. This new responsibility of pharmacists is to actively ensure that prescribed drug
therapy is.........
(a) Effective
(b) Safe
(c) Economical
(d) All

14. 2. With the therapeutic drug monitoring patient benefits............ .
(a) Medically
(b) Economically
(c) Both (a) and (b)
(d) None of these
3. Adverse reactions of drugs are a major public health problem and account for
of............% admissions to hospital medical services.
(a) 10_20
(b) 3-5
(c) 6_8
(d) None of these
4. It has been stated in the different studies that with more careful prescribing and
monitoring............% of these adverse reactions could be prevented.
(a) 20-230
(b) 40-50
(c) 60-80
(d) none of these
5. Hospitalized patients receive an............average of drugs.
(a) 2-3
(b) 8-10

15. (c) 5-6
(d) None of these
6. Nursing home patients receive an average.........of medications.
(a) 5-9
(b) 1-3
(c) 10-13
(d) None of these
7. Multiple drug therapy.............the probability of drug induced disease.
(a) Increases
(b) Decreases
(c) Does not affects
(d) None of these
8. Unit dose drug distribution systems have significantly reduced the occurrence
of...........
(a) ADR's
(b) Side effects
(c) Medication errors

16. (d) None of these
9. ..............is necessary for the pharmacist to assess the therapy.
(a) Skill
(b) Knowledge
(c) Proper Training
(d) positive attitude
10. A monitoring plan usually consists of a combination of...............parameters.
(a) Objective
(b) Subjective
(c) Both (a) and (b)
(d) None of These
11. For a problem involving drug administration ............. may be the professional
who can best solve the problem.
(a) Physician
(b) Nurse
(c) Pharmacist

17. (d) None of These
12. Monitoring determines the. ........... of the dosage regimen.
(a) Quality
(b) Efficacy
(c) Safety
(d) None of These
13. Pharm-D course is......... year doctoral course.
(a) 6
(b) 4
(c) 3
(d) None of These