1. The pharmacokinetics of the enantiomers of vigabatrin were investigated after oral administration of a single 50 mg kg‐1 dose of the racemate to two groups of six epileptic children (I: 5 months‐2 years, II: 4‐14 years). 2. The mean (+/− s.d.) values of maximum plasma concentration and area under the plasma concentration‐time curve of the R(‐) enantiomer were significantly higher than those of S(+) vigabatrin in both groups: R(‐) Cmax: 21 +/− 6.6 (I)‐41.3 +/− 13.9 (II) vs S(+) Cmax: 13.9 +/− 4.5 (I)‐23.8 +/− 12.2 (II) mg l‐1; R(‐) AUC: 106 +/− 28.5 (I)‐147 +/− 34 (II) vs S(+) AUC: 90.9 +/− 27.9 (I)‐117 +/− 26 (II) mg l‐1 h. In group I, the half‐life of the R(‐) isomer was significantly shorter than that of the S(+) isomer; in group II, the half‐lives were comparable. 3. For the R(‐) enantiomer the area under the curve, and the elimination half‐life increased linearly with age. 4. During chronic administration (50 mg kg‐1 vigabatrin racemate twice a day for 4 days), the morning trough plasma drug concentrations did not increase.

No abstract

We have evaluated whether vitamin B₆ and C metabolism may be altered by infection in the elderly. Vitamin B₆ and C biochemical status has been assessed for times over a period of 21 days (days 0, 7, 14, and 21) in 18 subjects ≧75 years. The subjects were divided into 3 groups: group I (8 subjects with acute infection), group II (4 malnourished subjects), and group III (6 control subjects). Vitamin B₆ status was determined by plasma pyridoxal-5’-phosphate (PLP) and erythrocyte aspartate aminotransferase activation coefficient (α-EAST), and vitamin C status by plasma ascorbic acid. During the 3 weeks, vitamins Be and C values were significantly different between groups: at days 7 and 14, PLP values were significantly higher in group III than in both groups I and II, and α-EAST values were significantly higher in group I than in both groups II and III. Plasma ascorbate values were significantly lower in group I than in both groups II and III. These data suggest that an acute catabolic state like infection may influence vitamin B₆ and C metabolism. Nevertheless, more work is needed to assert that vitamin B₆ and C supplementation may be useful during infection.

No abstract

1 Lamotrigine is a new antiepileptic drug, chemically unrelated to currently used antiepileptic medication. Its pharmacokinetics can be influenced by concomitant antiepileptic medication. 2 This study was performed to assess the pharmacokinetic profile of lamotrigine in three groups of children treated with different types of comedication: drugs known to induce, to inhibit or to have no clinically significant influence on drug metabolism, respectively. 3 Thirty‐one children aged 6 months to 5 years were included and received a 2 mg kg−1 single oral dose. Lamotrigine plasma profiles were different between the three comedication groups. The half‐lives (mean±s.d.) were: 7.7±1.8 h, 21.9±6.8 h, 44.7±10.2 h in the ‘inducer’, ‘other’ and ‘inhibitor’ groups respectively. 4 Patients were then dosed to steady state, with the dosage adjusted on the basis of the single dose pharmacokinetics to achieve a minimum plasma concentration between 1.5 and 3 mg l−1. The mean minimum plasma concentration for the three groups was 2.54±1.28 mg l−1 at steady state. 5 Dosage of lamotrigine can be optimised with knowledge of the metabolic effects of antiepileptic comedication.