Ketotifen is an antimalarial prodrug of norketotifen with blood schizonticidal and liver-stage efficacy. - Milner E; Sousa J; Pybus B; Auschwitz J; Caridha D; Gardner S; Grauer K; Harris E; Hickman M; Kozar MP; Lee P; Leed S; et al. (European journal of drug metabolism and pharmacokinetics, 2012)