Hazards may include:
(1) decreased activity of drug-metabolizing enzymes (cytochrome P450, other), causing accumulation of chemotherapeutic agent with increased toxicity
(2) increased activity of drug-metabolizing enzymes, causing increased clearance of the chemotherapeutic agent and decreased effectiveness
(3) toxic symptoms of the herbal therapy misinterpreted as toxicity from chemotherapy, resulting an unnecessary change in therapy
(4) interference with drug transporters (P-glycoprotein) which may decrease transport into cancer cells, resulting in decreased effectiveness
Herbs that can cause problems include:
(1) garlic (Allium sativum)
(2) ginkgo (Ginkgo biloba)
(3) Echinacea (Echinacea purpurea)
(4) ginsent (Panax ginseng)
(5) St. John's wort (Hypericum perforatum)
(6) kava (Piper methysticum)
A patient who is receiving cancer chemotherapy should be:
(1) asked about any herbal remedies
(2) instructed not to start any herbal remedies during chemotherapy
(3) instructed to stop any herbal remedies that could interfere with chemotherapy
(4) questioned about herbal use if unexpected side effects occur
(5) questioned about herbal use if chemotherapy is less effective than expected
