Phenytoin – serum
Last updated: Sunday, 21, March, 2004
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5 mL blood in plain tube.
| Therapeutic Interval||40-80 µmol/L (10-20 mg/L).|
Therapeutic drug monitoring.
Steady state is not achieved for several days. Re-testing after a change of dose should be delayed for 48 hours.
The half-life is 7-60 hours (dose dependent).
This drug exhibits Michaelis-Menten kinetics, that is, as serum levels rise a stage is reached when a small increase in dose causes a large increase in serum levels.
|Reference||Glauser TA and Pippenger CE. Epilepsia. 2000; 41(8): 6-15.|