In 1976, Tagamet (cimetidine) was approved in Britain, and three years later the FDA followed suit. It was the first drug designed to treat heartburn and ulcers by reducing the production of stomach acid, rather than simply trying to neutralize it with antacids. It worked very well. Its inventors, Smith, Kline and French (now part of Glaxo) were rewarded for their effort; Tagamet became the first $1 billion selling drug ever.
Ten years later, Prilosec (omeprazole) was launched by AstraZeneca, and it became one of the best selling drugs in history. Prilosec reduced stomach acidity, but by a different mechanism (it is a proton pump inhibitor, PPI, while Tagamet and others block a form of histamine that enhances acid production), and this class of anti-ulcer drugs was found to be superior to the Tagamet class. It is now on the World Health Organization s list of essential medicines.
But, the PPI class has been occasionally criticized for real or theoretical problems, including osteoporosis, an increased risk of C. diff infection, and the possibility of other infectious agents surviving in a less acidic stomach. Furthermore, there have even been claims that PPIs may increase the incidence of Barrett's esophagus (BE) , an erosion of the esophagus by stomach acid, which can then progress to esophageal adenocarcinoma.
ACSH s Dr. Gil Ross says,There is something strange going on here, since one of the uses of PPIs was to prevent esophageal cancer. It is difficult to rationalize how the same drug can both increase and decrease this rate.
Yet, this is exactly what is being discussed lately. In her October 25th op-ed in the New York Times entitled The Dangers of Eating Late at Night, Dr. Jamie Koufman, a specialist in acid reflux, says, The number of people with acid reflux has grown significantly in recent decades. Reflux can lead to esophageal cancer, which has increased by about 500 percent since the 1970s. And anti-reflux medication alone does not appear to control reflux disease.
Dr. Koufman cited a 2104 Danish study, which claims that PPIs do not not protect against Barrett's esophagus: No cancer-protective effects from PPI's were seen. In fact, high-adherence and long-term use of PPI were associated with a significantly increased risk of adenocarcinoma or high-grade dysplasia. While the authors do acknowldge that there could be confounders in their results that will require more study, Dr. Koufman maintains that the real culprit is late night eating.
This is unlikely to be resolved anytime soon, especially since other studies have observed a decrease in the progression of BE to esophageal cancer, and have recommended: We suggest that all patients with this condition, even those with no oesophagitis or symptoms, should be encouraged to continue long term PPI therapy.
More from Dr. Ross: The Danish study referred to failed to adequately control for a key factor in esophageal disease: alcohol intake. A letter in today s Times by an ENT Dr. at Mt. Sinai, Jonathan Aviv, summarizes the situation fairly well:
In fact, there is a role for medication in the treatment of acid reflux disease, and patients should not stop taking their medications without consulting their physicians.
The Danish study s authors acknowledged that they were unable to control for risk factors for esophageal cancer like alcohol consumption, which can alter the findings significantly. But numerous other studies suggest that P.P.I. s may give a protective effect against the precursor to esophageal cancer as well as to esophageal cancer itself.
I d like to emphasize this point: patients on PPIs should not fear this ostensible risk and should not discontinue their medication without discussing it with their doctor.