Medications for Alzheimer disease: Nursing pharmacology

Alzheimer disease is the most common cause of dementia, and although there’s no cure, certain medications can be used to help mitigate some of the symptoms and improve the client’s quality of life.

Now, these medications can be broadly divided into two classes; acetylcholinesterase inhibitors and NMDA receptor antagonists.

Starting with acetylcholinesterase inhibitors, these include rivastigmine, galantamine, and donepezil. Acetylcholinesterase inhibitors are taken orally, while rivastigmine can be taken in the form of a transdermal patch as well as orally.

Once absorbed into the bloodstream, they travel to the brain. Here, they inhibit the enzyme acetylcholinesterase, which normally breaks down the neurotransmitter acetylcholine.

As a result, acetylcholine builds up in the synaptic cleft, causing increased and prolonged effects. And since there's some evidence suggesting that Alzheimer disease is related to low levels of acetylcholine in the brain, acetylcholinesterase inhibitors can help improve symptoms.

However, increased acetylcholine levels can also cause cholinergic side effects like miosis, blurred vision, headaches, dizziness, and drowsiness.

At the same time, in the airways, acetylcholine triggers bronchoconstriction and increases bronchial secretions, which can manifest with dyspnea and a persistent cough.

In the cardiovascular system, acetylcholine slows down the heart rate and reduces blood pressure, which can result in bradycardia, heart block, hypotension, and even cardiac arrest.

In the gastrointestinal tract, these medications can cause increased motility and secretions, leading to nausea, vomiting, cramps, diarrhea, increased salivation, and involuntary defecation, or even gastrointestinal bleeding.