Study: Patient Adherence to Alzheimer’s Drugs Needs Improvement

While there are currently no treatments capable of curing Alzheimer’s disease, a class of drugs called acetylcholinesterase inhibitors are commonly prescribed to dementia patients to help slow the progression of the disease. As with any medication, it’s important that patients adhere to a dosage schedule in order to receive the full benefit of the drug.

A new study conducted by researchers at Indiana University Center for Aging Research and the Regenstrief Institute, has found that patient adherence to Alzheimer’s medications may be lacking. The results of the post-marketing study were published in the Journal of the American Geriatrics Society.

All three of the acetylcholinesterase inhibitors looked at in the study have been approved by the FDA, and require a period of four to six weeks in order to build the patient up to the most effective target dose. According to the researchers on the current study, after 18 weeks only 50 patients of the 196 patients were still taking the acetylcholinesterase inhibitors.

“While these medications do not change the course of the disease, by not getting patients to target doses, we aren’t optimizing the potential benefits these medications may provide,” said primary author Dr. Noll Campbell, IU Center for Aging Research and Regenstrief Institute scientist. “Unlike the clinical trials conducted by drug companies for FDA approval, this study was conducted with participants who were taking an average of 8 other medications – what we would call a ‘real-world’ population – individuals who are sicker than those who typically participate in drug company trials. Having a better understanding of those to whom the drugs are targeted may provide us with greater insight into how to increase benefits and reduce risk.”

Around half of those patients in the study experienced side effects associated with the medications – such as pain, dizziness, vomiting and diarrhea – early on in treatment, which contributed to their decision to stop taking the medications. Cost of medication also played a role in long-term medication adherence; patients were less likely to stop using the drug donepezil, which is often covered under US drug plans.

Patients prescribed one of the other acetylcholinesterase inhibitors, galantamine and rivastigmine, showed a 14 and 17 percent rate of stopping the medication due to cost reasons, respectively. Some of these patients switched to donepezil, and were continued to be monitored in the study to investigate the overall tolerability of the Alzheimer’s medication.

“Physicians should be aware of the impact of side effects, many of which are shared with other medications that the patient is taking, on both the adherence to the medication and quality of life,” said Campbell. “While these drugs aren’t the answer to Alzheimer’s disease, improving tolerability and adherence may reduce the complications of the disease.”

Overall, 53 percent of patients taking donepezil reached their target dose over the 18 week study period. This is compared to 19 percent for rivastigmine and 5 percent for galantamine.

“The current US drug trial approval process is just too long – typically 17 years – and inefficient with only a 14 percent hit rate from discovery to successful delivery,” said Dr.
Malaz Boustani, founder of the Indiana Clinical and Translational Sciences Institute’s IU Center for Health Innovation and Implementation Science and senior author on the publication. “We need to test the efficacy of drugs in real-world populations – as we did in this study – at the earliest phase of clinical trials.”