Loading
St John's wort is a herbal antidepressant whose active ingredient hyperforin switches on the liver enzyme CYP3A4 and the P-glycoprotein pump, cutting blood levels of irinotecan's active metabolite by 42% and imatinib by about a third. It is contraindicated with most tyrosine kinase, CDK4/6 and PARP inhibitors, and its effect lasts two weeks after stopping.
Hypericum perforatum induces CYP3A4 and P-glycoprotein through the pregnane X receptor. In a crossover pharmacokinetic study of five patients (Mathijssen et al., JNCI 2002), St John's wort reduced plasma levels of SN-38, the active metabolite of irinotecan, by 42 percent, enough to reduce efficacy; it lowers imatinib exposure by about a third and is contraindicated with most tyrosine kinase inhibitors, CDK4/6 inhibitors, PARP inhibitors, antiemetics such as aprepitant, and many antidepressants (serotonin syndrome). Its effect persists for two weeks after stopping. Depression in cancer patients should be treated with evidence-based psychotherapy or antidepressants chosen for their interaction profile. St John's wort is the clearest example of why oncology teams must ask about supplements at every visit.
Hyperforin activates PXR, increasing transcription of CYP3A4 and ABCB1, which accelerates clearance of drugs that are substrates of these systems.
The drug that started the targeted therapy era in 2001, turning chronic myeloid leukaemia into a manageable condition with near-normal life expectancy.
Irinotecan is a topoisomerase-blocking chemotherapy central to bowel and pancreatic cancer regimens (FOLFIRI, FOLFIRINOX, NALIRIFOX) and to salvage therapy in childhood sarcomas; it carries the same warhead as the deruxtecan ADC payloads.
Query for this technology: (TITLE:"St John's wort: an interaction to avoid" OR ABSTRACT:"St John's wort: an interaction to avoid") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about St John's wort: an interaction to avoid, not a curated reading list.
Shares Dietary supplements during cancer treatment: interactions and harms, Evidence-based integrative oncology, Imatinib, Toxicity and quality of life are undervalued and the tags complementary, supportive-care.
Shares Dietary supplements during cancer treatment: interactions and harms, Evidence-based integrative oncology, Misinformation and unproven therapies and the tags complementary, supportive-care.
Shares Dietary supplements during cancer treatment: interactions and harms, Evidence-based integrative oncology, Misinformation and unproven therapies and the tags complementary, supportive-care.
Shares Dietary supplements during cancer treatment: interactions and harms, Evidence-based integrative oncology, Misinformation and unproven therapies and the tags complementary, supportive-care.
Shares Dietary supplements during cancer treatment: interactions and harms, Evidence-based integrative oncology, Misinformation and unproven therapies and the tags complementary, supportive-care.
Shares Dietary supplements during cancer treatment: interactions and harms, Evidence-based integrative oncology, Misinformation and unproven therapies and the tags complementary, supportive-care.
Shares Dietary supplements during cancer treatment: interactions and harms, Evidence-based integrative oncology, Misinformation and unproven therapies and the tags complementary, supportive-care.
Shares Evidence-based integrative oncology, Psycho-oncology and distress screening, Toxicity and quality of life are undervalued and the tags complementary, supportive-care.