Mechanism of drug interaction between a Kampo medicine, byakkokaninjinto, and tetracycline in rats

<i>In vitro</i> study of interaction between quinine and <i>Garcinia kola</i>

“…Some authors have reported that G. kola reduced ciprofloxacin absorption in vitro [6], and reduced both the C max and AUC when co-administered with ofloxacin in humans [4,5]. Some authors have also reported a herb -drug interaction in which a Kampo preparation which contains various herbal medicines and metal cations such as calcium, magnesium and aluminum caused significant reduction in plasma tetracycline and ciprofloxacin concentrations in healthy volunteers through complex formation [8,9]. A significant pharmacokinetic interaction between quinine (an antimalarial medicine) and G. kola in healthy volunteers has earlier been reported and the results were suggestive of interference with quinine absorption since parameters indicative of interference with elimination were not significantly altered [7].…”