Researchers have set out to study whether the concurrent use of two common types of drugs for people with Alzheimer’s could end up creating a need for more medication prescriptions, including some that are high-risk for older adults with dementia.
By examining the health records of more than four million older adults on Medicare, the researchers will study whether prescribing drugs such as cholinesterase inhibitors and antimuscarinic drugs (a type of anticholinergic drugs used to treat urinary incontinence), could increase people’s risk taking drugs like antipsychotics, which are linked to increased risk of death for older adults with dementia.
Rajender Aparasu, a researcher of the study and a professor at the University of Houston College of Pharmacy, suggested the prescriptions of a cholinesterase inhibitor and an anticholinergic drug can trigger a domino effect which “is going to worsen the dementia state [of patients]. And it is going to lead to increased use of antipsychotics, which are generally used for patients with behavioral symptoms and [it] might also increase the use of memantine, which is generally used for severe dementia patients.”
After all, Aparasu said cholinesterase inhibitors and anticholinergic drugs may not mix well and lead to a series of side effects.
For example, cholinesterase inhibitors such as donepezil, commonly known under the brand name Aricept, are approved by the Food and Drug Administration to treat the symptoms of people with Alzheimer’s. Donepezil may slow down cognitive decline by stopping an enzyme from breaking down acetylcholine, a chemical that helps nerve cells send messages between one another. Nerve cells can then better sustain their connections with higher levels of acetylcholine.
While donepezil can temporarily ease the symptoms of Alzheimer’s for some people with the disease, it can also lead to side effects that include urinary incontinence as people lose control of their bladder.
Subsequently, clinicians may use anticholinergic drugs to treat the problem. According to Aparasu, therein lies the potential cascade of negative effects for people with Alzheimer’s. The two types of drugs work in opposite actions. While cholinesterase inhibitors increase levels of acetylcholine, anticholinergic drugs block the action of the chemical.
Previous research shows that anticholinergic drugs may increase older adults’ risk of cognitive decline. Aparasu and colleagues have also found in a past study that anticholinergic drugs are linked to increased risk of death among nursing home residents with depression.
“If cholinesterase inhibitors are increasing the risk of prescribing anticholinergics, and if those two medications are combined … what happens in terms of the patients’ outcomes?” Aparasu asked.
He said the team hopes to better inform doctors about the effects of the drug interactions and improve the quality of medication prescribed, so “they can take care of patients without hurting them.”