October 2, 2019
Many people with Alzheimer’s disease take the drug donepezil (brand name Aricept) to help ease symptoms for a time. But those on the drug should be aware of a rare but potentially life-threatening side effect. The drug can cause muscles to break down, leading to a condition called rhabdomyolysis that can lead to kidney damage and even death.
The risk of hospitalization for rhabdomyolysis was more than double that for those taking Aricept compared to other Alzheimer’s drugs, a new study reports.
Still, the condition is very rare, and anyone taking Aricept should not stop taking it. But because rhabdomyolysis is potentially very serious, patients should be aware of the problem and seek medical care should symptoms arise.
The main symptom of rhabdomyolysis, or rhabdo as it is commonly called, is intense muscle pain or weakness that does not go away. Urine can also turn dark. Emergency treatment is needed to manage the condition and may require a week or longer stay in the hospital.
For the study, Canadian researchers analyzed data on 220,353 men and women over age 65 who had gotten a prescription between 2002 and 2017 for one of three Alzheimer’s drugs: donepezil, rivastigmine (Exelon) or galantamine (Razadyne).
There were 88 hospitalizations for rhabdo among 152,300 patients taking donepezil (0.06 percent prevalence), compared to 16 cases among the 68,053 patients taking one of the other drugs (0.02 percent prevalence).
The authors note that doctors should rule out rhabdo if someone on an Alzheimer’s drug comes to the hospital because of constant muscle pain. Still, the condition remains very rare (about 25,000 per year in the U.S. from all causes), and most of the cases in the current study were not life-threatening.
Other medications may also trigger the condition, including antipsychotic medications, which are also often prescribed to people with Alzheimer’s disease to allay symptoms like agitation and aggression. Cholesterol-lowering statin drugs have also been tied to an increased risk of rhabdo. It is possible that Aricept cannot trigger rhabdo alone. Further studies will be required to determine what other cofactors might act with Aricept to trigger rhabdo.
The condition more commonly arises after intense physical exertion, often in people who have not been training regularly. The condition can arise in military recruits undergoing basic training, and in people beginning high-intensity workouts at the gym.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Jamie L. Fleet, Eric McArthur, Aakil Patel, et al: “Risk of rhabdomyolysis with donepezil compared with rivastigmine or galantamine: a population-based cohort study.” CMAJ – Canadian Medical Association Journal, Sept. 16, 2019