This document provides information on therapeutic drug monitoring, including sample information required for accurate interpretation and therapeutic ranges for various drugs. It discusses therapeutic drug monitoring for anti-seizure drugs like carbamazepine and valproic acid, cardiac drugs like digoxin and lidocaine, aminoglycoside antibiotics like amikacin and gentamicin, lithium for bipolar disorder, methotrexate for cancer treatment, theophylline, immunosuppressants for transplant patients like cyclosporine and tacrolimus, and various sample collection and testing methods. The goal of therapeutic drug monitoring is to ensure drug levels are within therapeutic ranges to achieve efficacy while avoiding toxicity.

1. THERAPEUTIC DRUG
MONITORING

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3. INTRODUCTION
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12. Sample Information Required for Accurate Interpretation
• Time of sample in relation to last dose
• Duration of treatment with the current dose
• Dosing schedule
• Age, gender
• Other drug therapy
• Relevant disease states
• Reason for request (e.g. lack of effect, routine
monitoring, suspected toxicity)

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19. Drug Indication Therapeutic Range
Carbamazepine psychomotorseizures, tonic-
clonic seizures, and mixed
seizures
4 – 10 μg/mL
Ethosuximide absence (petit mal) seizures 10 – 150 μg/mL
Primidone Improving seizure control and
reducing the risk of toxicity
2.5 – 20 μg/mL
Phenobarbital Febrile seizures and neonatal
seizures
15 – 40 μg/mL
Phenytoin Tonic-clonic
Seizures.
10 – 20 μg/mL
Valproic Acid Used to treat petit mal,
tonic-clonic, and myoclonic
seizures.
50 – 100 μg/mL

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23. • CLASS I – BLOCK THE FAST SODIUM CURRENT
CLASS II – BLOCK THE EFFECTS OF CATECHOLAMINE'S
CLASS III – PROLONG ACTION POTENTIAL AND HENCE REFRACTORINES BY BLOCKING K+
CLASS IV – BLOCK THE CARDIAC CALCIUM
NOTE: DIGOXIN AND DIGITOXIN DO NOT FALL NEATLY INTO ANY OF THESE CATEGORIES, THOUGH THEY
ARE UNDOUBTEDLY CARDIAC AGENTS

24. Drug Indication Therapeutic Range
Digitoxin congestive heart failure,
supraventricular tachycardia
10 – 30 ng/mL
Digoxin CHF AND SVT 0.9 – 2 ng/mL
Disopyramide Antiarrhythmic 1 – 30 μg/mL
Lidocaine DO 1.5 – 5 μg/mL
NAPA (N-acetylprocainamide) DO 10 – 30 μg/mL
Procainamide DO 4 – 12 μg/mL
Quinidine DO 0.5 – 8 μg/mL

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28. Drug Indication Therapeutic Range
Amikacin Most often used to treat severe
infections with multidrug
resistant gram-negative bacteria
Peak:* 15 – 30 μg/mL
Trough:* 1 – 10 μg/mL
Gentamicin Given to patients with
potentially life-threatening
bacterial infections. Excess
dosage can cause kidney
and auditory nerve damage
Peak: 5 – 10 μg/mL
Trough: 1 – 2 μg/mL
Netilmicin Used to treat serious
infections, particularly those
resistant to gentamicin
Peak: 1 – 12 μg/mL
Tobramycin Pseudomonas aeruginosa Peak: 5 – 10 μg/mL
Trough: 0.5 – 2 μg/mL
Vancomycin gram-positive cocci Peak: 30 – 40 mg/mL
Trough: 5 – 10 mg/mL

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32. ANTIMANICS
Antimanics Drugs Peak:
Indication Therapeutic Range
Lithium Used to treat bipolar disorders
to supplement other
antidepressant drugs
0.6 – 1.2 mmol/L
Test Methods
Immunoassay is the most common method used for monitoring these drugs.

33. ANTINEOPLASTICS
Antineoplastic Drugs Indication Therapeutic Range
Methotrexate Used in the treatment of
neoplast disorders
Peak: 0.1 – 2600 μmol/L
Test Methods
Immunoassay is the most common method used for monitoring these drugs.

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35. Drug Indication Therapeutic Range
Caffeine For use in the quantitative
analysis of caffeine levels
in human serum in subjects
undergoing therapy with
caffeine, especially in cases
of neonatal apnea
Peak: 1 – 30 μg/mL
Theophylline Used to relax smooth
muscles in bronchi and
pulmonary blood vessels
10 – 20 μg/mL

37. Drug Indication Therapeutic Range
Cyclosporine Aids in the management of cyclosporine therapy in
kidney, heart, and liver transplant patients
50 – 350 μg/L
Everolimus Aids in the management of certican therapy in
and heart transplant patients
3 – 8 μg/mL
Mycophenolic Aids in the management of mycophenolate mofetil
therapy in transplant patients
1 – 4 μg/mL
Tacrolimus Aids in the management of tacrolimus therapy
in kidney, heart, and liver transplant patients
3 – 15 μg/L
Sirolimus Aids in the management of rapamune therapy in
kidney transplant patients.
3 – 15 μg/mL

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