The Indiana University School of Medicine and Regenstrief Institute study focused mainly on antacids like ranitidine and famotidine, the most popular medications prescribed in the US.
Sold under brand names as Axid, Pepcid, Tagamet and Zantac, these drugs are used to treat ulcers, acid reflux and other gastrointestinal disorders.
The study included 1,558 cognitively normal African-Americans aged 65 and older. After controlling for other possible factors, nearly 18 percent of H2A users studied exhibited signs of cognitive impairment.
"Taking these medications continuously appears to put older African-Americans at greater risk for the development of cognitive impairment," said Dr. Malaz Boustani, lead author of the study, published in the Journal of the American Geriatrics.
"We need to study this further to determine how acid blockers might be causing or creating this effect and if it occurs only in African-Americans," the author added.