Ranitidine is a medicine used for the short-term treatment of heartburn. Available in supermarkets and pharmacies, a prescription is only needed when a higher dose of the medicine is required over a longer period of time.
Ranitidine (sold under brand names Zantac, Rani 2, and Ausran) is currently in the news because regulators have found that most formulations are contaminated with a chemical called NDMA, which is as a probable carcinogen.
When was it developed?
Ranitidine was first reported in the scientific literature in 1976, and became available in 1981.
Peptic ulcer disease had been a significant health issue affecting millions of people around the world and at the time of ranitidine coming to market, approximately four million people in the United States had active peptic ulcers, which resulted in 6,000 deaths per year.
At one stage, ranitidine, as sold under the Zantac brand name, was the best selling drug in the world.
However, the drug is now off-patent (available in cheap generic formulations) and is included on the World Health Organisation’s (WHO) list of essential medicines as an anti-ucler medicine.
How and why is it used?
Antacids work by either neutralising acid or reducing the production of stomach acid.
Ranitidine reduces the amount of acid produced in the stomach and is part of a larger family of drugs called H2-histamine receptor antagonists.
It is a type of antihistamine, but not the type used for treating allergies. This is because the chemical histamine, although involved in allergic reactions, also stimulates the production of stomach acid. So blocking the effect of histamine also reduces the production of stomach acid.
Ranitidine is commonly used to relieve the symptoms of heartburn and indigestion but has also been used in the past to treat more serious conditions, such as peptic ulcers.Dragana Gordic/Shutterstock
In recent times, longer lasting medications called proton pump inhibitors, that are more effective at reducing acid production, have largely replaced ranitidine for more serious conditions.
The most common formulations of ranitidine sold in pharmacies are oral tablets. For those patients who have difficulty swallowing, the medicine is also available as effervescent tablets (fast dissolving in a glass of water) and as a pre-prepared oral liquid.
What’s the link with cancer?
Ranitidine is currently in the news after the Australian Therapeutic Goods Administration (TGA) issued an alert stating many formulations of the drug were contaminated with a chemical called N-nitrosodimethylamine, abbreviated as NDMA. This should not be confused with the illegal party drug MDMA (ecstasy), which is a completely different chemical.
Contamination of ranitidine formulations is a problem because the World Health Organisation lists NDMA as a probable carcinogen, meaning it may cause cancer.
But it’s important to note most people are exposed to NDMA as part of their normal lives. NDMA can be found in cooked and smoked meats, from smoking cigarettes, beer, and even some toiletry and cosmetic products.
It’s not clear how the ranitidine formulations have become contaminated with NDMA. A similar chemical, dimethylamine, is used in the synthesis of ranitidine, and it may be possible some NDMA is created when the drug is made. Alternatively, ranitidine may be broken down, producing NDMA, during storage.
It will be important to determine the source of the contamination if new formulations are to be made free from NDMA.
The response in many countries has been the recall of ranitidine formulations. In the United States, the companies Sandoz and Apotex have voluntarily withdrawn their brands from sale. In Canada, the government has asked companies to stop distributing the medicine.
On September 17, Australia’s TGA said it anticipated a recall of ranitidine and until then would be working with international regulators and companies to investigate the problem. The TGA also announced it was doing batch testing of products to determine the extent of the contamination in Australia.
What if you’re currently taking ranitidine?
If the medicine works for you and you wish to keep taking it, there is no immediate health risk. The only issue is from long-term use and could mean a possible increase in your risk of cancer later in life.
If you do wish to stop taking ranitidine, your pharmacist or general practitioner will be able to recommend other heartburn medicines that may be effective for you.
Authors: Nial Wheate, Associate Professor | Program Director, Undergraduate Pharmacy, University of Sydney