Two weeks of it took 30 percent off a leukaemia drug's exposure
Clearance of imatinib sped up by 43 percent. In five patients on irinotecan the active form fell 42 percent, and the bone-marrow suppression that marks a working dose eased with it.
What the study found
Two weeks of it took a third off a leukaemia drug's blood level
Two weeks of St John's Wort sped up clearance of the leukaemia drug imatinib by 43 percent, cutting total exposure by 30 percent. In five patients on the chemotherapy drug irinotecan, the active form fell 42 percent, and the bone-marrow suppression that marks a working dose eased with it.
The caveat · Imatinib tested on healthy people
The imatinib study used twelve healthy volunteers given single doses, not patients whose disease was being controlled. The irinotecan study had five patients and its 42 percent estimate runs anywhere from 14 to 70 percent. Neither measured whether any cancer did worse.