A comparative pharmacokinetic study of conventional and chewable carbamazepine in epileptic patients.

Abstract

Using an open substitution study design, conventional carbamazepine (Tegretol, CBZ‐C and a chewable carbamazepine formulation (Tegretol Chewtabs, CBZ‐CHEW) were compared in 12 patients with severe intractable epilepsy. During a dosing interval, no significant differences were observed with respect to trough or peak serum concentrations of CBZ and CBZ‐10,11‐epoxide (CBZ‐E), the active metabolite. The area under the serum CBZ concentration‐time curve for a dosing interval was (mean +/− s.e. mean) 146 +/− 10 mumols l‐1 h on CBZ‐ C and 143 +/− 9 mumols l‐1 h on CBZ‐CHEW. The two formulations, therefore, have a similar pharmacokinetic profile and could be used interchangeably in the management of patients with epilepsy.

Comparative Pharmacokinetic Study of Chewable and Conventional Carbamazepine in Children

“…dependent side effects were recorded when CHEW was substituted for CONV. Our data confirm those collected by Patsalos (1990), Patsalos et al (1990), Chan et al (1985), and Maas et al (1987) in adults.…”

“…Few data are available concerning the tolerability and the pharmacokinetic profile of CHEW. In adults, (Patsalos, 1990;Patsalos et al, 1990) reported no differences in terms of efficacy and tolerability between CHEW and conventional (CONV) CBZ. Maas et al (1987) reported the interchangeability of the two galenic formulations in terms of their pharmacokinetic profiles.…”

Antiepileptic drugs—best practice guidelines for therapeutic drug monitoring: A position paper by the subcommission on therapeutic drug monitoring, ILAE Commission on Therapeutic Strategies

“…The rate of carbamazepine absorption is relatively slow, variable, and formulation dependent. The time required to reach peak serum concentrations (T max ) following single oral doses of immediate‐release tablets, chewable tablets, and suspension is in the range of 2–9 h, 1–7 and 0.5–4 h, respectively (Chan et al, 1985; Graves et al, 1985; Maas et al, 1987; Patsalos, 1990a). The bioavailability of carbamazepine is 75–85%, although the lack of an injectable formulation precludes precise determination of the exact value.…”

Bioequivalence of Carpine Tablets Containing Carbamazepine

“…Carbamazepine can exhibit erratic absorption after oral ingestion, with peak serum concentration (C max ) achieved within 2-8 hours. 3 The rate of absorption can differ markedly with different pharmaceutical formulations. Plasma protein binding of carbamazepine is 76% and may be decreased in newborns.…”

“…4 The active metabolite of carbamazepine, carbamazepine-10,11-epoxide, has been implicated and analyzed in carbamazepine toxicity. 3 It is generally accepted that seizure control is most effective when the plasma concentration of carbamazepine is kept within the range of 4-12 mg/L; concentrations exceeding the upper limit have been associated with toxic effects. 5 Transient, dose-related, central nervous system and gastrointestinal adverse effects including nausea, drowsiness, ataxia, vertigo, and diplopia may occur in as many as 50% of the patients whose concentrations are within the upper half of the therapeutic range, particularly with dose initiation and titration.…”