Researchers Study Link Between Pneumonia Risk and Antidementia Drugs

According to the Alzheimer’s Association, pneumonia is the most commonly identified cause of death for individuals with Alzheimer’s disease and dementia. A team of researchers in Finland recently studied the association between certain antidementia drugs and the increased risk of pneumonia.

There are 5.4 million Americans living with Alzheimer’s disease, which is the sixth leading cause of death in the United States overall, and the fifth leading cause of death for those ages 65 years and older. Alzheimer’s is one of the costliest chronic diseases, and in 2016, an estimated $236 billion will be spent on healthcare, long-term care, and hospice costs for those with the disease. Alzheimer's is the most common form of dementia; it is not considered a normal part of aging, because it is more of a progressive condition with marked loss of memory and intellectual abilities, which worsens over time. Confusion, disorientation, and mood and behavioral changes are some of the markers of Alzheimer’s disease, along with symptoms such as difficulty speaking, swallowing, and walking.

While researchers still don’t fully understand the reasons behind why brain cells in individuals with Alzheimer’s disease stop functioning properly, they have found that it has to do with a buildup of plaques, which are protein deposit fragments in the brain, and other twisted proteins, or tangles, which block normal communication between brain cells. Some buildup of plaques and tangles is a normal part of aging, but individuals with Alzheimer’s disease experience these changes to a much greater degree. Along with mental and behavioral changes, individuals with this severe form of dementia experience physical changes that make them susceptible to infections such as pneumonia, falls, bedsores, malnutrition, and more. Pneumonia is the fourth leading cause of hospitalization among individuals with Alzheimer’s disease, as those suffering with the condition are more vulnerable to lung infections and other severe infections.

As such, researchers from the University of Eastern Finland recently conducted an investigation into the risk of pneumonia in Alzheimer’s disease patients taking certain antidementia drugs. Their study, the first of its kind, was recently published in the journal Annals of Medicine, and in it they looked at two groups of medicines often prescribed to slow the advance of Alzheimer’s disease and dementia symptoms.

The first was Cholinesterase inhibitors (AChEI), a group of drugs that include donepezil, rivastigmine, and galantamine, which help in improving cognitive function for individuals with mild to moderate dementia, but give only marginal benefits to those with more severe forms of the disease. The second was memantine, which is an antidementia drug that works in a different way to improve behavior, daily activities, and global function, and gives some benefit to those with moderate to severe dementia.

The team researched the risk of pneumonia associated with the use of AChEI drugs and memantine in 65,481 people diagnosed with Alzheimer’s disease that had been using one of these drugs from 2005 to 2011. Along with prescription data, the team looked at data on pneumonia diagnoses from hospital discharges as well as causes of death registers. The AChEI drug donepezil was the most frequently used antidementia drug, followed by rivastigmine, memantine, and galantamine. The researchers found that the risk of pneumonia was higher among users of rivastigmine and memantine, though upon analysis, only the transdermal patch of rivastigmine was associated with higher pneumonia risk.

Nonetheless, the authors noted that their findings may have less to do with the drugs themselves and more to do with the relative health of the patients on these medications. “The risk of pneumonia among those who used memantine monotherapy was 1.6 times higher than the risk of those on donepezil,” the authors explained in their paper. “Memantine is well tolerated and has less adverse effects than AChEIs, so it is likely that the drug itself is not associated with increased pneumonia risk. Use of memantine is associated with disease severity, and therefore the increased risk for pneumonia may be due to more advanced stage of dementia. This may also explain higher pneumonia risk associated with concomitant use of AChEI and memantine compared with donepezil use found in sensitivity analyses. In addition, the use of memantine was more common among the eldest population than among younger persons.”

The Alzheimer’s Association notes that while there is currently no cure for Alzheimer’s disease, medications and treatments are available to slow the progression of disease symptoms and improve quality of life for those with dementia.