TESTS IN FOCUS

Therapeutic Drug Monitoring Information for Clinicians​

DrugSample typeTime of Sample Collection
​​​​Therapeutic Ranges ​ ​
​ ​ ​
Valproic Acid

​​​​ 

​​​
​ ​ ​
​ ​
Trough​​​​50 - 100 µg/ml ​ ​ ​​ ​ ​
TegretolTrough​​​​4-12 µg/ml​​ ​ ​ ​ ​
PhenytoinTrough​​​​10-20 ug/ml
PhenobarbitalTrough
​​​​10-40 ug/ml ​ ​ ​ ​ ​

 

Gentamicin

Peak testing (exactly 1 h after start of infusion of 3rd dose, or 1st dose in critically ill patients) Trough

Adults Multiple daily do​se

Peak: 4-10 ug/ml

Trough: 1-2 ug/ml​

​Adult Once daily dose

Trough <1 ug/ml


Pediatrics trough conc.: <2ug/ml
VancomycinTrough concentrations should be obtained prior to the fourth or fifth dose.
​Therapeutic concentration >10 ug/ml
​ ​
Trough 15-20 ug/ml

 

Amikacin

Peak testing (exactly 1 h after start of infusion of 3rd dose, or 1st dose in critically ill patients) Trough

​Amikacin-Once daily dose

Trough = <1.0 ug/ml Peak = 56-64 ug/ml​

​​Amikac​​​in-Multiple daily dose

Trough = 5-10 ug/ml Peak = 15-30 ug/ml

 

 

Cyclosporin

 

 


Trough​

Post renal transpla​nts: Upto 2 months 200-300 ng​/ml

3 months 200 ng/ml

4-12 months 80-180 ng/ml

Post liver transplants:

≤ 1 month 350-450 ng/ml

2-6 months 250-350 ng/ml

>6 months 170-240 ​ng/ml

Post bone marrow transplants:

First 3-4 weeks 200-

300 ng/ml

Until 3 months 100-

200 ng/ml

TacrolimusTrough​​Target range for trough sample 3-20 ng/ml ​ ​ ​
Toxic >20 ng/ml

 

Methotrexate


​Trough or sample collected after 72 hrs of therapy

​​​​ 

Non-toxic concentration <0.1 umol/l

Lithium

​ 

 

​ ​
Trough (Predose or after 12 hours post dose)
​​Therapeutic Range: 0.6 - 1.2 mmol/l​
​ ​ ​
Toxic: >2.0mmol/l
TheophyllinePeak testing (after 2-4 hours post dose) Trough
​​​​Therapeutic Range 10-20 ug/ml
​ ​ ​ ​ ​
DigoxinPeak (after 8 hours post dose) Trough
​​Therapeutic Range 0.6-1.2 ng/ml
​ ​ ​
Toxic >2.0ng/ml
​​​​​​​Special instruction: Mention drug dosing frequency, route and sample is trough or peak. Mention STAT on the request slip if results are needed shortly. ​ ​ ​ ​ ​ ​ ​ ​


  • Where trough is predose sample