An Example of Drug Interactions
At Drugs.com there is a drug interaction checker. By typing the name of the chemotherapy drug in a box, you can receive a comprehensive list of possible drug interactions with both prescription and non-prescription drugs. Trying the drug "methotrexate", a popular chemotherapy choice for breast, head and neck, skin or lung cancers, also used for rheumatoid arthritis and severe psoriasis, brings up a total of 632 drugs known to interact with methotrexate. Of these, 165 are major interactions, 437 are moderate, and 30 are minor.
For example, in checking the list one finds these commonly used over the counter drugs on it: acetaminophen, alka-seltzer, ibuprofen, kaopectate, and sinutab. Commonly used presciption drugs like penicillin and percodan also made the list.
In the food and lifestyle interactions with methotrexate, there are cautions about using it in conjunction with caffeine and alcohol. The following herbs and nutritional supplements were mentioned as possibly problematic: black cohosh, chaparral, comfrey, DHEA, kava, pennyroyal oil, and red yeast rice.
Though checking online is not a substitute for medical counseling, it is possible to see the vast amount of research that has been done on this subject. At their worst, drug interactions can be fatal. At best, they can interfere with the positive effects of chemotherapy on cancer cells.