Cassia angustifolia and tacrolimus interaction in a liver transplant patient, a case report

Abstract

Cassiaangustifolia isaspeciesofplant fromtheSennafamilythathastraditionally beenusedasalaxativeindifferentherbalproductsandcommercialmedicines.Even thoughtherearefewdocumenteddrug–plant interactions, theuseofC.angustifolia withdifferent drugsmay have additive effects, such aswithother laxatives or potassium-depletingdiuretics. Itsusealso increasesperistalsiswhich,may reduce drugabsorption.Thecombinationwithdigoxinhasbeenassociatedwithanincreased riskofdigoxintoxicity,probablyduetoanincreaseinplasmadigoxinconcentrations andhypokalaemia.Wepresentacasewithsupratherapeutictroughconcentrationof tacrolimus, animmunosuppressiveagent, andaherbal product ina liver transplant patient after concomitant intake of tacrolimus and a herbal product based on C.angustifolia,suggestingapossibledrug–lantinteractionthroughbyP-glycoprotein. Weobservedanincreaseinthepatient’sbloodconcentration2.8-foldandthearea under thecurveat steadystate2.1-fold. This interactioncouldbeof clinical relevance,giventhedose-dependentsideeffectsof tacrolimus, suchasnephrotoxicity, neurotoxicity,hypertension,hyperglycaemia,orelectrolytealterations.