Joensuu, Finland—The risk of developing pneumonia for patients on antidementia drugs is greatest for those using memantine, although rivastigmine patches also appear to increase the likelihood, recent research suggests.

Looking at cases of the lung infection leading to hospitalization or death, patients using memantine or rivastigmine patches had a 1.6 and 1.15 times higher risk of pneumonia, respectively, although no elevated risk was documented for those taking rivastigmine orally, states a report in the Annals of Medicine.

On the other hand, use of donepezil or galantamine was linked with the lowest risk of pneumonia, according to a nationwide register-based study, the Finnish Medication and Alzheimer’s disease trial called MEDALZ, conducted at the University of Eastern Finland. Study authors tout their research as the first to compare the risk of pneumonia associated with different antidementia drugs and drug forms.

For the study, researchers compared the risk of pneumonia among users of different antidementia drugs, focusing on 65,481 Alzheimer’s disease patients, all living at home in Finland, during 2005-2011.

Results indicate that the risk of pneumonia was higher in persons using the rivastigmine patch, adjusted hazard ratio (HR) 1.15, and memantine, HR 1.59, compared with donepezil users. No increased risk was seen with oral rivastigmine, HR 1.08, or galantamine, HR 0.91.

Researchers note that the results were not affected by adjustment for comorbid conditions, use of psychotropic drugs, or inverse probability of treatment weighting.

Background information in the article points out that, while no cure for Alzheimer’s diseases currently exists, the progression of the disease can be slowed down by antidementia drugs, such as memantine and acetylcholinesterase inhibitors such as donepezil, galantamine, and rivastigmine. It also states that Alzheimer’s disease patients have an elevated risk of pneumonia, which is a common cause of death in that population.

“The increased risk of pneumonia in this fragile group of aged persons should be taken into account,” study authors advise. “Memantine is associated with the highest risk in the comparison of antidementia drugs.”

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