Oxcarbazepine - Profile of a new anticonvulsant (Trileptal)

In February 2000 the antiepileptic drug (AED) oxcarbazepine (OXC, Trileptal) has been approved for treatment in Germany. Thus, there is a new AED available for adults and children from the age of six years on with focal epileptic seizures with and without secondary generalisation. OXC is appropriate for mono- and add-on-therapy. From the chemical structure, there is much similarity to the well-known carbamazepine (CBZ), the only difference is the presence of a keto group in the tricyclic ring of the molecule, that results, however, in a metabolism of OXC as »pro-drug« to the effective metabolite monohydroxy derivative and in a reduction of auto-and hetero-induction. In contrast, CBZ is mainly metabolised to an epoxide which is suggested to be responsible for most of the related side-effects of this drug. According to scientific data, the effectiveness of OXC is comparable to well established AED, such as CBZ, valproate, phenytoin or lamotrigine, while OXC is considered to be better tolerated than some of the more »traditional« AEDs. The most common side effects of OXC are dizziness, vertigo, nausea, drowsiness, allergies with rash, and hyponatremia, which is, in general, clinically asymptomatic. According to our own observations, a fast dosage increase or conversion from CBZ to OXC is - in contrast to common recommendations - often poorly tolerated. Thus, we suggest a more cautious dosage adaptation. Drug interactions are less frequent compared to the potent hepatic enzyme inductor CBZ, nevertheless OXC may reduce the effectiveness of hormonal contraception. The treatment costs of OXC are twice to three times higher than CBZ, but still remain significantly below the level of the majority of the new AEDs.