Clinical pharmacology of Lamictal
Absorption
Lamictal is quickly and totally absorbed when given orally, and plasma concentrations have an apparent linear relationship to dose.
Distribution and metabolism
The drug is approximately 55% bound to plasma proteins. The liver metabolizes Lamictal to inactive glucuronide conjugates that are excreted in the urine.
The half-life of Lamictal taken alone is about 25 hours, but it rises to 70 hours in patients also taking valproate. In patients also taking hepatic enzyme–inducing AEDs, the half-life of Lamictal drops to 14 hours.
Steady state
Steady state is reached after 3 to 15 days, depending on whether Lamictal is taken with enzyme-inducing AEDs, valproate, or neither.
