Primidone and Tegretol

In the database of official manuals used in the service creation an interaction registered by statistical results of studies was found, which can either lead to negative consequences for the patient health or strengthen a mutual positive effect. A doctor should be consulted to address the issue of joint drug administration.

Using primidone together with carBAMazepine may alter the effects of carBAMazepine. Contact your doctor if your condition changes or if you experience loss of seizure control. If your doctor does prescribe these medications together, you may need a dose adjustment or special test to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

MONITOR: Coadministration with primidone may decrease the plasma concentrations of carbamazepine and increase concentrations of its active 10,11-epoxide metabolite. The mechanism is primidone induction of CYP450 3A4, the isoenzyme responsible for the metabolism of carbamazepine to carbamazepine-10,11-epoxide (CBZ-E). In one case report, carbamazepine levels were persistently low and subtherapeutic in a 15-year-old boy receiving carbamazepine and primidone for the treatment of partial complex seizures. Increasing the carbamazepine dosage only modestly increased serum levels but did not control the seizures. Adequate control was achieved only after gradual withdrawal of primidone, which led to a substantial increase in carbamazepine serum levels, a reduction in CBZ-E levels, and a 60% reduction in total carbamazepine clearance. Conversely, carbamazepine has also been reported to decrease the plasma concentrations of primidone and increase levels of phenobarbital derived from primidone. In clinical and pharmacokinetic studies, primidone levels were typically lower when the drug was administered with carbamazepine than when administered alone, and phenobarbital levels generally higher. The proposed mechanism is carbamazepine induction of the metabolism of primidone to phenobarbital.

MANAGEMENT: Serum drug levels and seizure control should be monitored more closely when carbamazepine or primidone is added to or withdrawn from a stabilized anticonvulsant regimen, and the dosages adjusted as necessary.

Primidone

Generic Name: primidone

Brand name: Mysoline

Synonyms: n.a.

What is Primidone?

Tegretol

Generic Name: carbamazepine

Brand name: Carbatrol, Epitol, Equetro, Tegretol, Tegretol XR, Tegretol, Tegretol XR

Synonyms: n.a.

What is Tegretol?