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A drug used to help Alzheimer’s disease symptoms was associated with a small increased risk of hospitalization. Getty Images
  • New research finds a common drug to treat Alzheimer’s disease symptoms may increase the risk of a condition called rhabdomyolysis.
  • Rhabdomyolysis occurs when muscle fibers break down.
  • The overall risk remains low.

New research finds a drug used to treat symptoms of Alzheimer’s disease is associated with a two-fold increased risk of developing a condition that can lead to kidney failure.

According to the study published in the Canadian Medical Association Journal today, using donepezil (Aricept) increases the risk of hospitalization for rhabdomyolysis, a painful condition caused by the death of muscle fibers, compared with other cholinesterase inhibitors.

“Health Canada and the U.S. Food and Drug Administration have issued warnings about the risk of rhabdomyolysis with donepezil use. We wanted to examine this issue further, using a much more rigorous study design and following the outcomes of over 150,000 older adults who newly started donepezil,” study author Dr. Amit Garg, PhD, and Professor at Western University’s Schulich School of Medicine & Dentistry in Ontario, Canada, told Healthline.

Researchers at Western University analyzed data from publicly funded administrative health services records in Ontario via the ICES databank. They looked at information for more than 220,000 participants 66 years or older in Ontario, Canada, with a recent prescription for donepezil (Aricept), rivastigmine (Exelon) or galantamine (Razadyne), three cholinesterase inhibitors typically used to manage Alzheimer disease and other dementia.

Garg’s findings suggest that donepezil is associated with a two-fold higher risk of hospitalization for rhabdomyolysis or 0.06 percent risk, compared to the two other commonly prescribed dementia drugs at 0.02 percent risk.

While the overall risk was small, it was statistically significant.

“Reassuringly, the chance of being hospitalized with rhabdomyolysis after starting donepezil remains very low, and patients should not be alarmed,” Garg said.

He cautioned that people should never stop taking their prescription drugs without speaking to a doctor first. “We didn’t assess risk and benefits in this study. Rather we only wished to better understand one type of risk with these drugs.”

Cholinesterase inhibitors are a type of drug that treat dementia by blocking the normal breakdown of acetylcholine, the body’s main neurotransmitter which helps nerve cells communicate with each other.

Recent research finds it’s not clear whether these drugs can improve quality of life, reduce psychological symptoms like depression and anxiety, or even delay the point at which people will need full-time care.

Although experts emphasize that no change in symptoms is also considered an improvement.

According to Keith Fargo, PhD, director of scientific programs and outreach at the Alzheimer’s Association, when side effects do occur, “They’re fairly minimal. The cholinesterase inhibitors are very well tolerated and you’re typically talking about a little gastrointestinal upset for most people. This tends to eventually resolve, lots of medications can affect people this way.”

Regarding the risk of rhabdomyolysis, “it’s very rare, something like a fraction of 1 percent — and even in those who had it, it wasn’t severe,” he said. “I think that the fact that we have medications that can do anything for people with Alzheimer’s disease is a blessing, and the benefits of these drugs, although not as great as we’d like, appear to outweigh the very small risk of side effects.”

According to Dr. James Elder III, DO, internist at Texas Health Harris Methodist Southwest Hospital Fort Worth and Texas Health Physicians Group, rhabdomyolysis is characterized by the breakdown of muscle tissue that releases material from inside the muscles to the bloodstream.

These materials include a building-block of muscle called myoglobin, which may cause myoglobinuria — a condition that can result in life-threatening kidney failure.

Causes of rhabdomyolysis “can include electric shock, crush injuries, heat-related injury like heat stroke, and the use of some medications,” Elder said.

“Although rhabdomyolysis may occasionally be life-threatening, by far the majority of cases are not. Recovery is generally full and complete in non-fatal cases. Treatment is generally supportive: increased hydration — either by IV in a hospital or orally at home for mild cases, correction of electrolyte imbalances, if they occur and very rarely dialysis,” he said.

Elder explained that symptoms of rhabdomyolysis can include muscle pain or weakness, especially in muscles of the thighs, shoulders, and low back. Sometimes it accompanied by dark reddish-brown urine, muscle swelling, fatigue, fast heartbeat, and increased thirst.

Stopping or slowing Alzheimer’s disease has been a struggle for the medical community, and even these drugs may not do much to help combat the disease.

Recent studies show that the overall benefits of taking cholinesterase inhibitors may be slight for patients with Alzheimer’s disease. Researchers from the Institute for Quality and Efficiency in Health Care in Cologne, Germany, pointed to galantamine as an example.

They reviewed studies that found the medication had improved thinking skills and memory in only about 14 out of 100 people who used it, and believe that other drugs of this type have a similar effect on cognitive performance.

Rivastigmine, available orally and as a patch, shows very weak evidence that it can improve cognitive function. This weak effect was only observed with the patch.

“They stop cognition from getting worse for a period of time. They don’t last forever — six months to a year is what the average person can expect and you don’t significantly get worse in terms of your cognition during that period,” said Fargo.

New research finds that donepezil, a type of Alzheimer’s disease drug called a cholinesterase inhibitor, can double the odds of being hospitalized with a condition called rhabdomyolysis.

Rhabdomyolysis is when muscle cells break down and in severe cases can cause kidney damage. However, the odds of experiencing this condition are still very low.

Experts say the most common side effect for this class of drugs is stomach upset, which usually resolves over time.