Donepezil, most commonly known as the brand name Aricept, is one of the more popular drugs used to treat symptoms of dementia and Alzheimer’s disease. Now, a new study finds that Aricept may lead to a rare condition known as rhabdomyolysis, which causes muscle breakdown.
Alzheimer’s and Cholinesterase Inhibitors
Currently, there are no drugs that can prevent or cure Alzheimer’s or dementia. But cholinesterase inhibitors have been approved by the U.S. Food and Drug Administration (FDA) to treat certain symptoms of the diseases, like memory loss and thinking problems, according to the Alzheimer’s Association.
Cholinesterase inhibitors help prevent the breakdown of acetylcholine, which plays a role in memory and learning. These drugs may delay some of the symptoms of dementia, but their effect is different for each person.
Aricept is one of the more popular cholinesterase inhibitors, and the second drug approved by the FDA for Alzheimer’s treatment. One study ranked Aricept as the most effective drug for delaying Alzheimer’s symptoms.
It has, however, been linked to various side effects, like nausea, diarrhea, loss of appetite, vomiting and muscle cramps. And in 2015, the Government of Canada issued a warning about Aricept’s link to rhabdomyolysis as well as a neurological disorder known as neuroleptic malignant syndrome (NMS).
Aricept and Rhabdomyolysis
The study focused on three cholinesterase inhibitors — donepezil (Aricept), rivastigmine (Exelon) and galantamine (Razadyne) — that are used to manage dementia symptoms.
The researchers, from Western University’s Schulich School of Medicine & Dentistry and Lawson Health Research Institute, examined data from ICES, which include administrative health services records for Canada’s Ontario population. They tracked how over 220,000 people aged 66 or older, who had a new prescription for donepezil, rivastigmine or galantamine, were managing their Alzheimer’s and dementia symptoms.
Donepezil (Aricept) in particular had twice as high of a risk of being hospitalized for rhabdomyolysis than the other cholinesterase inhibitors. In rhabdomyolysis, the breakdown of tissue releases muscle fibers into the blood, which can have a damaging effect on the kidney.
“The findings of this population-based cohort study support regulatory agency warnings about the risk of donepezil-induced rhabdomyolysis,” Dr. Jamie Fleet, a postgraduate resident in physical medicine and rehabilitation at McMaster University, and an author of the study, wrote.
If you’re taking Aricept, should you be worried? The good news is that the incidence of this happening is still quite low. The researchers calculated that hospital admissions for rhabdomyolysis in the population they examined occurred at about six in 10,000 prescriptions, or only 0.06 percent.
“Reassuringly, the 30-day incidence of a hospital admission with rhabdomyolysis after initiating donepezil remains low,” the authors wrote.
The researchers still aren’t sure why Aricept may contribute to the risk of this muscle condition, writing in the study that “the biological mechanism of donepezil-associated rhabdomyolysis is unknown.”
They did, however, note that acetylcholine, the chemical that Aricept intervenes, is associated with neuromuscular junction and muscle movement. “Theoretically, preventing the breakdown of acetylcholine may lead to abnormalities in muscle contraction and ultimately rhabdomyolysis,” the authors conclude.
More research will be needed to confirm the results and further understand the biological link between Aricept and rhabdomyolysis.