Therapeutic Drug Information

Clinical Biochemistry

These ranges were replaced with ranges in MASS units on April 2007 and then to National Pathology Harmonisation Ranges in April 2012.
Click here to view the new ranges.

Drug	Therapeutic Range	Units	Half life	Sampling Time	Time to Steady state
Carbamazepine	15 - 50	umol/L	12 hrs	pre-dose	2 - 6 days
Digoxin	1.0 - 2.5	nmol/L	36 - 48 hrs	At least 6hrs post-dose	5 - 7 days
Lamotrigine	4 - 30	umol/L	20 - 30 hrs	pre-dose	4 - 15 days
Phenobarbitone	65 - 170	umol/L	96 hrs	pre-dose	10 - 25 days
Phenytoin	40 - 80	umol/L	7 - 42 hrs	pre-dose	7 - 35 days
Theophylline	55 - 110	umol/L	3 -13 hrs	pre-dose (or see below)	2 -3 days
sampling time:	oral dosing - pre and/or 2 - 4 hrs post dose infusion - sampling at least 2 hrs into a 24hr infusion
Valproic acid	350 - 700	umol/L	8 - 20 hrs	pre-dose	2 - 4 days

N.B. Toxic effects for some drugs may be observed at the upper limit of therapeutic levels.
N.B. To aid interpretation, time of sampling relative to the dose must be specified.

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