One of the more frequent questions I am asked by patients is whether they can continue to take, or should start taking, certain vitamins, herbals, or other complementary medications with their cancer therapy. It is estimated that at least 60% of cancer patients engage in complementary or alternative medical practices and with an increase in availability of both products and information, this is likely on the rise. Limitations in quality literature and concerns over lack of US Food and Drug Administration (FDA) oversight, along with questionable product purity and accurate labeling, have made many healthcare professionals rightfully hesitant to make helpful recommendations to patients beyond “use at your own risk.”
Two of the trials were negative in terms of benefit, two determined ginger was similar in benefit to metoclopramide, and three trials demonstrated some benefits.
Ginger’s proposed antiemetic mechanism of action is through possible competitive antagonism at the 5-HT3 serotonin receptors, via the rhizome constituents that can stimulate saliva, bile, gastric secretions, and galanolactone. It is not metabolized by the CYP enzyme system, making drug interactions unlikely, though reports have shown ginger may increase concentrations of tacrolimus. Along with the known side effect of gastrointestinal upset and dermatitis, increased bleeding is a rare but serious effect. The increased risk of bleeding is due to inhibition of thromboxane and platelet aggregation. Though this effect appears to be dose- and formulation-dependent, patients at risk for bleeding, especially those on antiangiogenesis inhibitors or anticoagulants, should avoid its use given that safer options are available for the treatment and prevention of CINV. Possible increases in blood glucose have also been reported.
So, where, if anywhere, does ginger fit into prevention of nausea in patients receiving chemotherapy? Given the limited data, evidence-based literature supporters would argue against its use in practice. However, patients without bleeding risk or diabetes who desire incorporation of ginger into their preventative treatment may be able to do so without harmful effects, after understanding the risks and benefits.