Drug levels in the blood (anti-epileptic drug: Trileptal®)

Oxcarbazepine (Trileptal®, Novartis Pharma GmbH) the keto derivative of carbamazepine, and its active metabolite (10-OH oxcarbazepine, or MHD) have distinctive anti-epileptic properties. Trileptal is suitable both for monotherapy and for combination treatment with other anticonvulsants. Its effectiveness has been demonstrated in generalised tonic and tonic-clonic seizures, with and without secondary generalisation.

The mechanism of action of oxcarbazepine and its major metabolite is only partially understood. It is assumed that both substances (similar to the structurally related carbamazepine and its active metabolite carbamazepine epoxide) stabilise overstimulated neural membranes, inhibit neural discharges and decrease the spread of synaptic pulses.

Pharmacokinetics
Oxcarbazepine is very rapidly and almost completely absorbed (95%) when taken. Immediately following absorption, it is reduced to a 10-monohydroxy derivative, the major active metabolite. This metabolite is the pharmacologically active component in humans.
The kidneys carry out over 95 % of the elimination of oxcarbazepine and the 10-hydroxy derivative. Only a small part of 10-hydroxy oxcarbazepine is converted into the inactive metabolite (dihydroxy carbamazepine).

Test material
1 ml of serum (shelf life of the samples: one week at 2-8 °C, with deep-frozen storage required for longer periods)

Therapeutic range
Dose adjustment is required, depending on the efficacy of and tolerance to the drug.

Reference values
Oxcarbazepine: < 3.0 µg/ml
10-OH oxcarbazepine: 5-30 µg/ml

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