Irinotecan (CPT-11) an anticancer prodrug is a potent inhibitor of acetylcholinesterase but is rapidly catalyzed to its active metabolite SN-38 97-ethyl-10-hydroxycamptothecin) a potent inhibitor of topoisomerase I.
CPT-11 is hydrolysed by carboxylesterases in human pig and rabbit. Horse BChE hydrolyses 200 times faster CPT-11 than human BChE