If you are currently being treated with any of the following medications, you should not use glutamine supplements without first talking to your health care provider.
Cancer Therapy -- Glutamine may increase the effectiveness and reduce the side effects of chemotherapy treatments with doxorubicin, methotrexate, and 5-fluorouracil in people with colon cancer. Similarly, preliminary clinical studies suggest that glutamine supplements may prevent nerve damage associated with a medication called paclitaxel, used for breast and other types of cancers.
However, laboratory studies suggest that glutamine may actually stimulate growth of tumors. Much more research is needed before it is known whether it is safe to use glutamine if you have cancer.