Short-term effects of Garcinia cambogia extract on the pharmacokinetics of lamotrigine given as a single-dose in Wistar rats

Garcinia cambogia supplements are widely used for weight loss. Knowing that epilepsy patients are at greater risk of developing overweight/obesity, the investigation of herb-drug interactions involving antiepileptic drugs of narrow therapeutic index is fully justified. This work was planned to assess potential pharmacokinetic-based interactions between G. cambogia extract and lamotrigine (LTG) through two independent pharmacokinetic studies. In the first study (co-administration study), rats were orally co-administered with a single-dose of G. cambogia extract (821 mg/kg) and LTG (10 mg/kg). In the second study (pre-treatment study), rats were orally pre-treated for 14 days with G. cambogia extract (821 mg/kg/day), being LTG administered (10 mg/kg) on the 15th day. Rats of the control groups received water instead of the extract. Following LTG administration, blood samples were collected until 96 h post-dose, and plasma LTG concentrations were determined and submitted to a non-compartmental analysis. Globally, no statistically significant effects were identified in the co-administration study of G. cambogia extract and LTG. In the 14-day pre-treatment study, a statistically significant decrease in the rate of systemic exposure to LTG and an increase of apparent volume of distribution were found. Even so, a minor or no clinical impact is expected from the administration of G. cambogia dietary supplements and LTG.