McCaskill's push for FDA review of herb/chemotherapy interactions called an intrusion into doctor/patient relationship

By Hank Schultz

- Last updated on GMT

"Much of the currently available data on herb-drug interactions is based on in vitro studies," said Stefan Gafner, PhD chief scientific officer of the American Botanical Council. Image: iStockPhoto
"Much of the currently available data on herb-drug interactions is based on in vitro studies," said Stefan Gafner, PhD chief scientific officer of the American Botanical Council. Image: iStockPhoto

Related tags Food and drug administration Dietary supplement Pharmacology

Industry stakeholders called Sen. Claire McCaskill’s recent call for FDA scrutiny of supplement interactions with chemotherapy treatments unnecessary and an intrusion on doctor/patient relationships.

Mike Greene, vice president of government relations for the Council for Responsible Nutrition, said what Sen. McCaskill, the senior Senator from Missouri and the ranking Democrat on the Senate Special Committee on Aging, is seeking is best handled as part of a doctor/patient relationship and should not be the purview of regulators. Those supplements and natural foods which have demonstrated drug interactions, such as St Johns Wort or grapefruit, are generally well known.

“Cancer is serious so when an individual is afflicted with this disease it is important that the lines of communication be open to their physician or other health care providers,”​ Green told NutraIngredients-USA. “All of what a patient is taking needs to be communicated to their physician.”

Dan Fabricant, PhD, CEO and executive director of the Natural Products Association, took a similar stance. Improvements in getting a complete and accurate patient history, including a patient’s supplement intake, could certainly help guide a physician. But FDA is not the tool to make this happen, he said.

“Does Sen. McCaskill really want the FDA to do what doctors took an oath to do?  It’s absurd to suggest that the FDA should get between a doctor and a patient,”​ Dr Fabricant said.

There’s not a product or supplement on the planet that is designed to interact with cancer patients undergoing chemotherapy. Plenty of foods such as grapefruit juice can cause potential interactions in patients taking prescription drugs and that’s why it’s important for anyone thinking about taking a supplement to speak first with a doctor,” ​he added.

Potential for confusion

Stefan Gafner, PhD chief scientific officer of the American Botanical Council, did say that McCaskill has touched upon a question that is potentially confusing for both doctors and their patients, but said that it is one that is unlikely to cause a safety concern.

“I have heard from physicians and pharmacists alike that they do not know where to find data on herb-drug interactions. Much of the currently available data is based on ​in vitro studies using isolated liver enzymes involved in metabolizing active pharmaceutical drugs, but most often, these tests on isolated enzymes may point to a potential for herb-drug interactions which ultimately turn out to lack clinical relevance,”​ Dr Gafner said. The issue, he said, is that some interactions of herbs with chemotherapy drugs that look to have the potential to cause problems in theory, such as a echinacea and docetaxel, have proved not to cause problems in practice.

Dr added that there are a number of resources available for clinicians to consult concerning potential herb/drug interactions. These include the ABC Clinical Guide to Herbs​, the Natural Products Comprehensive Database​, the American Herbal Products Associations Botanical Safety Handbook​, 2nd edition, and a database maintained by Dr Francis Brinker, ND.

Loren Israelsen, president of the United Natural Products Alliance, echoed both McCaskill’s and Gafner’s concerns: “We share the senator’s concern that cancer patients receive appropriate treatments with the most information possible. The questions surrounding the interactions between foods, supplements and medications, including in cancer treatment, is not a new topic, and it continues to be a matter of interest  for doctors and their patients. A fair amount of research has been done on this issue over the last 15 years, and more is in process,” ​he said.

"There are two additional considerations that we should all focus on: informed use of supplements by patients and informed health care providers, who know which supplements their patients are using. When patients fear their doctors will be dismissive of supplement use, patients may not tell them. This is understandable, and so we hope all sides will work together to create a treatment environment where open communication is the rule,”​ Israelsen added.

Sen. McCaskill and supplements

Sen. McCaskill has become increasingly vocal against the presence of “fraudulent or unsafe dietary supplements”​ in the marketplace.

She opened an inquiry into brain health supplements​ last summer by sending letters to the FDA and 15 major retailers after launching an inquiry into products, regulations, and retailers in the dietary supplement industry that specifically market to seniors using claims about improving memory and treating dementia and Alzheimer’s disease.

She also called on the FDA to suspend sales of supplements containing vinpocetine and picamilon​ pending an investigation. When the Agency was perceived to not be acting quickly enough, Sen McCaskill wrote to the 10 retailers to ask them to voluntarily remove any picamilon supplements​.

Earlier this year she requested a comprehensive list of enforcement actions​ taken by the Department of Justice related to the dietary supplement industry.

Greene said CRN has tried to shy away from a combative stance with Sen. McCaskill and instead has tried to foster on an ongoing dialogue with her staff in an attempt to address her concerns.

“We are in ongoing communication with her staff.  We have worked with her office on her other concerns such as product claims and Alzheimer’s, and we are going to try to be as helpful as we can with these latest concerns,” ​Greene said.

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