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THERAPEUTIC DRUG MONITORING
Therapeutic drug monitoring allows clinicians to more accurately titrate drug dosages, thus enhancing
individualization of therapy.
With the development of improved analytical techniques, the
clinician is able to predict the therapeutic or toxic
effects by monitoring the relationship between serum
concentrations and response of the patient.
Therapeutic drug monitoring can be a useful adjunct to patient therapy by facilitating drug dosage
adjustments
and reducing the risk of adverse effects associated with higher serum concentrations. Examples of drugs
for which
therapeutic drug monitoring may be indicated are shown below.
Testing for many therapeutic drugs is performed at
HealthLink Lab. What is not available here, we send to Quest
Laboratories in Atlanta.
IMPORTANT: Do not use serum separator tubes for the
therapeutic drug monitoring or toxicological
analyses. The gel barrier material will bind to lipophilic
substances, resulting in a falsely low drug
concentration report. Collect the specimen in a tube with no
anticoagulants or preservatives. Use a pipet
to transfer serum to a plastic vial.
|
HalfLife
|
Therapeutic Range
|
|
Generic Name
|
Trade Name
|
(Hours)
|
At Steady State*
|
|
ANTIEPILEPTICS
|
Primidone |
Mysoline®
|
6-20
|
5-12 mg/L |
|
|
Phenobarbital |
Luminal®
|
4 days
|
1540 mg/L |
|
|
Phenytoin |
Dilantin®
|
8-60
|
10-20 mg/L |
|
|
Carbamazepine |
Tegretol®
|
20-30
|
4-10 mg/L |
|
|
Clonazepam |
Clonopin®
|
19-60
|
10-80 mg/L |
|
|
Ethosuximide |
Zarontin®
|
30-60
|
40-100 ug/L |
|
|
Valproic Acid
|
Depakene®
|
6-15
|
50-100 mg/L |
|
CARDIAC DRUGS
|
Digoxin |
Lanoxin®
|
30-40
|
0.5-2.0 ng/mL
|
|
|
Digitoxin |
Digitoxin |
4-10 days
|
10-30 mg/L |
|
|
Procainamide |
Pronestyl®
|
2.5-5
|
4-10 mg/mL |
|
|
Quinidine |
Quinidine Sulfate
|
5-12
|
2-5 mg/L |
|
|
Lidocaine |
Xylocaine®
|
5-5 |
1.5-5.0 mg/L |
|
|
Disopyramide |
Norpace®
|
3-11
|
5 mg/L |
|
|
Tocainide |
Tonocard®
|
11-17
|
4-10 mg/L |
|
ANTIBIOTICS |
Chloramphenicol |
Chloromycetin®
|
1-4 |
10-25 mg/L (peak)
|
|
|
Gentamicin |
Garamycin®
|
2 |
5-10 mg/L (peak)
|
|
|
Tobramycin |
Nebcin®
|
2-4 |
5-10 mg/L (peak)
|
|
|
Amikacin |
Amikin®
|
2-3 |
20-25 mg/mL (peak)
|
|
|
Vancomycin |
Vancocin®
|
6 |
30-40 mg/mL (peak)
|
|
PSYCHOTHERAPEUTIC
|
Lithium |
Lithane®
|
8-15
|
0.8-1.2 mEq/L
|
|
AGENTS
|
Amitriptyline |
Elavil®
|
17-40
|
120-250 ng/mL**
|
|
|
Nortriptyline |
Aventyl®
|
15-93
|
50-140 ng/mL |
|
|
Imipramine |
Tofranil®
|
6-24
|
150-250 ng/mL**
|
|
|
Desipramine |
Norpramin®
|
12-76
|
50-300 ng/mL |
|
MISCELLANEOUS
|
Theophylline |
Aminophylline®
|
4-6 |
10-20 mg/mL |
|
DRUGS |
Salicylate |
Aspirin |
3-6 |
50-100 mg/L (analgesic)
|
|
|
|
|
|
100-300 mg/L |
|
|
|
|
|
(antiinflammatory)
|
*REPRESENTATIVE DRUGS FOR WHICH THERAPEUTIC DRUG MONITORING MAY BE
BENEFICIAL.
Halflife values are listed to guide in setting sample collection time for steadystate concentration and
pertain to adult dosages only.
For pediatric values call the laboratory.
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