Limited study should be a reminder to pharmacists
Many elderly Americans still are being prescribed potentially inappropriate medications, according to a study published in the August issue of the Archives of Internal Medicine.
The study should be a red flag reminding pharmacists to take a second look at an elderly person’s medications, says Nicole Brandt, PharmD, CGP, BCPP, assistant professor of geriatric pharmacotherapy and director of clinical and educational programs at the Peter Lamy Center on Drug Therapy and Aging. The center is located in the department of pharmacy practice and science at the University of Maryland School of Pharmacy in Baltimore. "Many of these drugs may not be entirely effective for older individuals compared to other drugs, and they may also have more side effects and potentially lead to other negative consequences," she says.
Researchers look at a PBM
To examine the number of potentially inappropriate medications being prescribed to the elderly, researchers conducted a retrospective cohort study using the outpatient prescription claims database of a large national pharmaceutical benefit manager (PBM), AdvancePCS of Irving, TX, and Scottsdale, AZ. The researchers compared the database with the Beers revised list of medications that should usually be avoided in elderly patients.
"In the whole scheme of things, [the drugs on the list] have been deemed inappropriate medications because there are other, safer alternatives for older individuals," Brandt says. "Other drugs are available that have fewer side effects, have fewer drug interactions, and have a better efficacy profile."
In the study, the researchers found that 162,370 subjects (21%) filled a prescription for one or more drugs of concern. Amitriptyline and doxepin accounted for 23% of all claims for Beers list drugs, and 51% of those claims were for drugs with the potential for severe adverse effects. More than 15% of subjects filled prescriptions for two drugs of concern, and 4% filled prescriptions for three or more of the drugs within the same year. The most commonly prescribed classes were psychotropic drugs and neuromuscular agents.
Amitriptyline in older individuals is very anticholinergic, Brandt says. "You could monitor for anticholinergic activities, but the key thing is that a lot of our older individuals have memory problems. This potentially could worsen it and cause them to be delirious."
Other agents in the realm of tricyclic antidepressants aren’t as anticholinergic and can be just as beneficial without having as many side effects, which include dry mouth, confusion potential, constipation, and worsening of glaucoma, she adds. "They seem to be tolerated a little bit better in terms of their side effect profile."
Amitriptyline common for diabetic neuropathy
Ruth Emptage, PharmD, assistant professor of clinical pharmacy, pharmacy practice and administration at The Ohio State University School of Pharmacy in Columbus, agrees that there are other choices in most of the cases of the medicines that are on the Beers list of inappropriate drugs. Amitriptyline might not be a bad choice for some of these patients, but limitations in the study do not make it possible to know for sure, she says.
The researchers admit that the study has several limitations:
- The results reported may overestimate potentially inappropriate prescribing for the uninsured.
- Certain drugs may be used at very low doses as last-resort treatments for the management of pain (amitriptyline) or urinary incontinence (doxepin).
- These data provide no direct insight into the outcomes associated with the use of prescription drugs.
- The researchers cannot be certain that the drugs prescribed and dispensed were actually consumed.
- Finally, and most importantly, there are no data on the reasons why certain prescription choices were made by a specific clinician for a specific patient.
Amitriptyline is listed as an antidepressant, but it may not necessarily be used for that property, Emptage says. "It appears to be the agent most effective for treating diabetic neuropathy. I’m sure that in some of the cases [with the elderly patients], amitriptyline is not the best; but some of the alternatives for diabetic neuropathy aren’t all that effective, or the formularies may not cover them."
The PBM’s preferred formularies may definitely affect which medications the elderly patients are being prescribed, she says. The researchers conclude that the "common use of potentially inappropriate drugs should serve as a reminder to monitor their use closely.
The key is to remember that you are dealing with a cohort of older individuals, Brandt suggests. "Is this person really tolerating the drug? [Older individuals] are more sensitive to these side effects. They are more likely to experience these adverse effects or use additional concomitant medications that can be problematic."