Alzheimer’s patients taking the antidementia treatment Namenda (memantine) are at high risk of developing pneumonia, and this risk is elevated in those using Exelon patches (rivastigmine), according to a recent study.
But, its researchers also noted, these medications are most often those used by people with advanced dementia, a “fragile” patient population.
Published in the Annals of Medicine, the study, “Use of antidementia drugs and risk of pneumonia in older persons with Alzheimer’s disease,” compared four antidementia treatments: donepezil, rivastigmine (oral and transdermal), galantamine, and memantine, in terms of their association with cases of pneumonia in users.
Investigators at the Kuopio Research Center of Geriatric Care at the University of Eastern Finland evaluated 65,481 Alzheimer’s patients, diagnosed in Finland between 2005 and 2011. The patients were part of the nationwide register-based study (MEDALZ) conducted by the university.
Pasi Lampela’s team compared the risk of pneumonia hospitalization or death among those taking Namenda, or an acetylcholinesterase inhibitor such as Exelon, with the risk seen in those taking the two other antidementia treatments. An acetylcholinesterase inhibitor prevents the breakdown of a neurotransmitter that influences brain function.
Researchers found the risk of pneumonia was 1.6 times higher among Namenda users (11,024 patients) and 1.15 times higher among Exelon patch users (9,709 patients), than among donepezil (brand name Aricept) users ( 26,416 patients). The use of oral Exelon (7,384 patients) and galantamine (brand names Razadyne and Razadyne ER) (10,948 patients) was not associated with an increased risk of pneumonia.
Pneumonia is one of the most common causes of hospitalization among Alzheimer’s patients.
When researchers adjusted the data to take into account variables such as additional diseases in patients or their use of psychotropic drugs, study results held up, they reported.
The research team believes that the increased risk of pneumonia among Namenda and Exelon-patch users may be explained in part by these treatments being used primarily by patients with advanced states of dementia. However, they also noted that these patients largely lived at home, according to a news release.
“The increased risk of pneumonia in this fragile group of aged persons should be taken into account,” the study concluded. “Memantine is associated with the highest risk in the comparison of antidementia drugs.”
Namenda and the acetylcholinesterase inhibitors Exelon, Aricept and Razadyne have been shown to halt the progression of Alzheimer’s.