Like some 60 million Americans, I have been taking OTC drugs for heartburn medicines for years.
Two years ago, I checked with my gastroenterologist, and she prescribed two antacid prescription drugs-- one of them was a 300 mg ranitidine tablet.
In late September 2019, news media began reporting the voluntary recall of Zantac, and over-the-counter ranitidine. Chain pharmacies, grocery stores, and discount supermarkets pulled ranitidine from their shelves, and customers received letters about the ranitidine recall.
Why?
The U.S. Foodand Drug Administration (FDA)1 reported that some batches of ranitidine might contain low levels of an impurity, NDMA (N-nitrosodimethylamine). It’s a possible carcinogen—i.e., it may cause cancer.
The FDA news releases reported that it was testing ranitidine products from multiple manufacturers, and asked manufacturers to test their ranitidine products for NDMA.
Because not all ranitidine medicines were being recalled, the FDA recommended consumers should talk with their physicians about options and consider other anti-acid reflux products.
Beingconcerned, I emailed my gastroenterologist and searched the Web for more information about NDMA and ranitidine.
My gastroenterologist’s medical assistant emailed back that saying that I should check with my pharmacist.
I did. The pharmacist said ranitidine tablets were not contaminated, but the capsule forms could be. At home, I opened my new ranitidine prescription—I had received ranitidine capsules.
On my next visit to my pharmacist, I ask the pharmacy technician to check my ranitidine prescription to see if it was recalled. He said I needed to bring my ranitidine prescription back so they could check the manufacturer and lot numbers.
A week later, I returned with my ranitidine prescription.
I asked the pharmacy technician, could you check my prescription. His response was, “I don’t know how” and turned away.
Could I see the pharmacist?
He came to the counter, looked at my prescription, logged onto the pharmacy’s computer database, and checked the manufacturer and lot number of my ranitidine. My ranitidine was OK to use.
I returned home and searched the Web for more information and what “a possible carcinogen” meant.
I found the American Cancer Society’s webpage (http://www.cancer.org/) with useful explanations about determining carcinogens and information for consumers.
The American Cancer Society (AMC) 2 uses two agencies that assess chemicals that may cause cancer: assessment: The World Health Organization’s International Agency for Research on Cancer (IARC)3 and The U.S. Department of Health and Human Service’s National Toxicology Program (NTP)4. Both websites explain how they analyze agents and classify them under their carcinogen classification system.
The below discussion provides a brief overview.
The American Cancer Society points out that testing for causes of cancer is hard. Exposing people to possible sources, often called agents, to see if they get cancer is unethical. Scientists use data from diverse sources.
IARC uses scientific data from (1) Situations where people work, live, travel, or visit and might be exposed to agent that cause cancer; (2) Epidemiological studies—of populations of people with cancer and where they may have been exposed to agents; (3) Experimental laboratory studies of cancer—exposing laboratory animals to agents to see if they develop cancer; (4) Experimental studies of animals as to how cancer develops when exposed to agents.
For its classification, the NTP uses scientific data from (1) cancer studies of experimental animals; (2) studies of the mechanism of carcinogenesis--i.e., how cancer forms; and (3) cancer in humans (populations).
Classification of agents (chemicals, drugs, and other compounds) is complex. See each of the respective organization’s websites for details.
Briefly, IARC classifies agents as Group 1: carcinogen to humans; Group 2: Evidence of carcinogenicity in humans and animals ranges from positive. but not conclusive, to carcinogenicity evidence is not available in humans to carcinogenicity evidence in animals; (3)
Group 3: Agent cannot be classified as a carcinogen to humans; (4) Group 4: Agent probably not a carcinogen to humans—lack of carcinogenicity in humans and experimental animals.
The NTP classifies agents as (1) Known to be a human carcinogen; (2) Reasonably anticipated to be a human carcinogen; (3) delisted—i.e., for different reasons—human data inadequate, no U.S. residents exposed, or other reasons.
Both organizations provide reports of possible cancer-causing agents and ongoing reviews of other potential cancer-causing agents.
For more details, see the IARC and NTP websites.
Notes & Resources
1 U.S. Food and Drug Administration (FDA) website: https://www.fda.gov/home) provides links to diverse information on drugs. Scrolling to the bottom of the home page provided links to ranitidine recall and explanations as of 24 October 2019. Access 24 October 2019.
2 The American Cancer Society provides a brief discussion explaining something as a carcinogen or not. (https://www.cancer.org/cancer/cancer-causes/general-info/determining-if-something-is-a-carcinogen.html). Accessed Access 24 October 2019.
3 The International Agency for Research on Cancer (IARC) https://www.iarc.fr/cards_page/iarc-research/ Accessed 24 October
2019. IARC is a division of the World Health Organization
4 The US National Toxicology Program (NTP). https://ntp.niehs.nih.gov/ Accessed 24 October 2019. NTP is a program of the U.S. Department of Health and Human Services.
Past Blogs
Blog # 1. A Closer Look at Rabies.
Blog # 2. Do You Have A Rabid Animal in Your Yard?
Blog # 3 How to Protect Yourself and Your Children from Rabies?
Blog # 4. If You’ve Been Exposed to Rabies, What Is the Treatment?
Blog # 5. Exploring Zoonotic Diseases.