Alzheimer’s Drugs Increase Risk for Falls, Hip Fracture, Pacemakers

One of the major abnormalities in Alzheimer's dementia is that the brain lacks enough acetylcholine, a neurotransmitter associated with short term memory. Drugs that help remedy this deficit have been on the market for many years. While it was known that these drugs also can have effects on the heart, the extent of the risk has not been fully appreciated. A new study documents a clear and important risk from these medications.

The Problem

Neurotransmitters last only seconds. Acetylcholine is dissolved by an esterase. Aricept, Exelon, and Razadyne all work the same way. These dementia drugs block the esterase, allowing the acetylcholine to last longer, so it has more “punch” even if there is less of it.

The problem is that acetylcholine is also an important transmitter in other parts of the body. In parts of the body where there is no deficit of acetylcholine, giving it more punch with these drugs can cause an excess of acetylcholine effect. In the heart, this leads to slow heart rate—bradycardia—which can decrease the heart’s pumping action.

Inadequate heart pumping leads to less oxygen delivered to the brain, then fainting. Fainting leads to falls, and falls lead to hip fracture, a very serious event, especially in older people.

Even if bradycardia does not lead to falls, it can lead to an Emergency Room visit or a hospital admission and insertion of a cardiac pacemaker. In most studies evaluating a new drug, otherwise healthy people are subjects. How often these undesirable events occur in real-world (unselected) populations had not been systematically studied.

The Study

Researchers looked at data from records of older people with dementia in Ontario, Canada. They identified over 19,000 people who were treated with one of these drugs, and compared them to over 61,000 age-matched people who were not.

The outcomes they felt might be associated with drug use were:

Syncope (fainting)
Bradycardia (excessively slow heart rate)
Placement of a permanent heart pacemaker
Hip fracture (which was associated with falling)
Subjects who received one of the drugs were about 75% more likely to have syncope (adjusted hazard ratio [HR] 1.75); 70% more likely to have bradycardia (HR 1.69); about half again as likely to need a pacemaker (HR 1.49); and about 20% more likely to suffer a hip fracture (HR 1.18).

Implications

Many believe these drugs are useful for Alzheimer’s dementia, but the extent of their value is often debated. The researchers who did this study remind readers that “Treatment decisions [for dementia] need to be individualized and should involve a discussion with patients and their caregivers about the expected benefits and potential risks of treatment.”


Source : seniors-health-medicare.suite101.com