Safety evidence on the administration of L. (bladderwrack) extract and lamotrigine: data from pharmacokinetic studies in the rat.

is often incorporated in weight loss dietary supplements to improve weight loss in overweight adults. Obesity is a common condition in epilepsy patients and is indeed increasing in refractory epilepsy and in patients under polytherapy. Since lamotrigine (LTG) is a first-line antiepileptic drug, used in monotherapy or adjunctive therapy, the main objective of this work was to investigate the potential pharmacokinetic-based interactions between and LTG in rats. In a first pharmacokinetic study, a single oral dose of extract (575 mg/kg, p.o.) was co-administered with a single-dose of LTG (10 mg/kg, p.o.). In a second study, rats were orally pretreated with extract (575 mg/kg/day, p.o.) for 14 days and received LTG (10 mg/kg, p.o.) on the 15th day. In the control groups, rats received water instead of the extract. After LTG administration, blood samples were taken until 96 h post-dose, and LTG concentrations measured in plasma were submitted to a non-compartmental pharmacokinetic analysis. The co-administration of extract and LTG caused no significant changes in the drug kinetics. However, the repeated pretreatment with extract significantly reduced the peak concentrations of LTG and caused a slightly decrease in the extent of systemic drug exposure. Overall, based on these results, no significant clinical impact is expected from the administration of dietary supplements and LTG.