On a caregiver-related email-based discussion list, an article on the link between dementia and antacids was mentioned. The specific antacids mentioned were the family that includes Zantac, Pepcid and Tagamet. Like antihistamines, these histamine-2 receptor antagonists are anti-cholinergic. People with dementia are not supposed to take anti-cholinergic medication. This is the first I've heard that there's an increased risk of getting dementia if one takes an anti-cholinergic (or histamine-2 receptor antagonist).
I found a good article on the subject in the LA Times, and have copied it below (along with the link to the article on the web). Following that is the PubMed abstract for the study being covered in the newspaper article.
http://www.latimes.com/news/nationworld ... nes-nation
Acid inhibitors may raise dementia risk
A study of elderly blacks indicates that those who are chronic users are more likely to develop the disease. The drugs inhibit a chemical involved in memory.
By Thomas H. Maugh II
Los Angeles Times Staff Writer
August 4, 2007
Elderly African Americans who are chronic users of acidinhibiting medications in the family that includes Zantac, Pepcid and Tagamet have 2 1/2 times the normal risk of developing dementia, Indiana researchers reported Friday.
The drugs block production of stomach acid by inhibiting so-called histamine-2 receptors; a pump in the stomach releases hydrochloric acid when stimulated by histamines.
But they also inhibit the brain's cholinergic system, which is involved in memory and cognition. Low levels of cholinergic activity have previously been linked to dementia.
There have been hints that the drugs, known as histamine-2 receptor antagonists, might be linked to dementia, but previous studies have come down on both sides of the question, said Dr. John Morris of Washington University in St. Louis, who was not involved in the study.
"This is certainly not the final word on the potential risk of these drugs," he said. "But what it tells us is that, for older adults, drug use should be considered very carefully."
Dr. Constantine G. Lyketsos, a psychiatrist at Johns Hopkins University, who was also not involved in the study, said: "This is one of the medicines we worry about when people with Alzheimer's are taking them. It can make memory worse and lead to confusion. Whether they will make it more likely that someone will develop Alzheimer's or dementia is still an open question."
GlaxoSmithKline, which manufactures Tagamet and Zantac, did not return calls seeking comment.
The study did not look at other races, and there was not enough data to suggest a risk from a different family of acidinhibiting drugs called proton pump inhibitors, which includes Prilosec, Nexium and Prevacid.
The histamine-2 receptor antagonists are among the most commonly prescribed medications in the United States, with more than 16 million prescriptions dispensed in 2005 in addition to over-the-counter sales. They are used to treat ulcers, acid reflux and other gastrointestinal disorders.
The study, published in the Journal of the American Geriatrics Society, was conducted by Dr. Malaz Boustani, a geriatrician at the Indiana University School of Medicine. He said he noticed that a significant number of his hospitalized patients appeared confused when they were taking medications to reduce acid reflux.
To explore the link, he looked at 1,558 black Indianapolis residents who had taken part in other studies through the school. None had dementia when the study began.
Each member was surveyed for use of the histamine antagonists and other drugs at the beginning of the study, at the end of three years and at the end of five years. The team also physically checked their medications.
The researchers found that, when they controlled for possible confounding factors, those taking the drugs were 2.42 times more likely to have dementia, which is marked by confused thinking, poor memory and impaired reasoning powers.
Boustani said he was not yet prepared to suggest that people stop taking the drugs. The proton pump inhibitors, he noted, are associated with an increased risk of osteoporosis, so that "if you switch, you then might deal with other alternatives.
"This is a very limited study in a specific population, but it picked up a signal that really needs to be confirmed," Boustani said. "The picture is really not clear yet."
Journal of the American Geriatrics Society. 2007 Aug;55(8):1248-53.
The association between cognition and histamine-2 receptor antagonists in african americans.
Boustani M, Hall KS, Lane KA, Aljadhey H, Gao S, Unverzagt F, Murray MD, Ogunniyi A, Hendrie H.
Indiana University Center for Aging Research, and Regenstrief Institute Inc., Indianapolis, IN, and Department of Medicine, School of Pharmacy, Unviersity of North Carolina, Chapel Hill, North Carolina, USA.
OBJECTIVES: To evaluate the association between histamine-2 receptor antagonist (H2A) exposure and incident cognitive impairment in a community-based sample of African Americans.
DESIGN: Five-year longitudinal observational study.
PARTICIPANTS: A sample of 1,558 community-dwelling African Americans aged 65 and older with no baseline cognitive impairment living in Indianapolis, Indiana.
OUTCOME MEASURE: Incident cognitive impairment, defined as incident dementia, cognitive impairment without dementia, or poor cognitive performance, as determined using combined cognitive assessments that included the Community Screening Instrument for Dementia, a comprehensive clinical assessment including informant interview, and neuropsychological testing.
EXPOSURE: Trained interviewers assessed the use of prescription and over-the-counter H2As using in-home inspection of medications and report of participants and informants.
RESULTS: Incident cognitive impairment occurred in 275 (17.7%) participants. After controlling for age, education, baseline cognitive score, the use of anticholinergics, and history of diabetes mellitus and depression, continuous use of H2As was associated with greater risk of incident cognitive impairment than for nonusers (odds ratio=2.42; 95% confidence interval=1.17-5.04).
CONCLUSION: H2As might be a risk factor for the development of cognitive impairment in African Americans. This finding requires confirmation from future studies.
PubMed ID#: 17661965