2, 0 timer og 1, 5 timer og falder bieksponentielt med en middelterminal halveringstid på ca.
Plasma concentrations of total topotecan (i. e. lactone and carboxylate forms) and topotecan lactone (active moiety) peak at approximately 2.0 hours and 1.5 hours, respectively, and decline bi-exponentially with mean terminal half-life of approximately 3.0 to 6.0 hour.