The elderly make up 12.7% of the U.S. population, but consume 34% of all prescription medications. As patients age, they undergo biological changes that affect the way medications are absorbed, distributed throughout the body, and eventually eliminated. There are also changes in the way medications act, down to the cellular level. These are known as pharmacokinetic and pharmacodynamic changes. The bottom line is that a therapeutic dose for a younger patient may be toxic for a senior. Therefore, a patient’s ability to tolerate a medication must be considered for each medication.
Dosing considerations include evaluation of kidney function, liver function, patient age, weight, and other factors. Medications that are removed by the kidneys can be problematic in the absence of renal function evaluation. This is evaluated by calculating the Creatinine Clearance (CrCl) and Glomerular Filtration Rate (GFR). Many prescribers will admit ball parking an estimate of kidney function by looking t the serum creatinine (SCr) level only.
The SCr can be normal, but the CrCl can be dangerously low when the other variables are applied. Likewise, a patient with reduced liver function, administered medications metabolized by the liver, can have disastrous unintended consequences. Many medications have maximum geriatric doses established in peer-reviewed literature. Others are deemed potentially inappropriate for use in the elderly. The work of Mark Beers, MD, revolutionized the way the elderly are treated with medications. “The Beers Criteria” or “The Beers List” is often cited whenever discussing elderly medication use.
The complexities of the medication regimen may have an effect on the ability to achieve therapeutic outcomes. Every medication added to the regimen not only increases the odds of drug interactions and adverse events, but also makes the regimen more difficult to follow.
Medication non-adherence rates range from 40-80% and account for up to a quarter of all nursing home admissions and 11% of elderly hospital admissions, according to recent literature.* Reasons for non-adherence vary from cost issues to patients who feel overmedicated and desire to make their own treatment decisions.
As mentioned, cost may influence whether or not a patient takes a medication as prescribed or not. While prescription drug plans cover many medications, many are not covered due to step therapy or formulary issues. Many patients fall into the sample medication trap, where they get started with samples, which are provided as a marketing tool by the pharmaceutical companies. Once the samples run out, patients sometimes find themselves paying huge sums out of pocket, rather than seeking equally effective, less-costly alternatives.
Inappropriate Prescribing for Older Patients
As mentioned previously, the Beers Criteria includes drugs that should be avoided in the elderly, as well as doses that should not be exceeded in others. Despite all of the effort to reign in inappropriate prescribing to the elderly, up to 25% of older patients still have at least one Beers Drug on their medication regimen.
Examples include some of the older antidepressants, like amitriptyline (Elavil); allergy and sleep aid, diphendydramine (Benadryl); long-acting anxiety agents like diazepam (Valium) and chlorazepate (Tranxene); and the weak narcotic-analgesic propoxyphene (Darvon, Darvocet). It is important to note that propoxyphene products were shown to be no more effective than Tylenol alone in several studies and has been recently recommended for removal in the U.S.
Other medications have recommended maximum daily geriatric doses, while others should be avoided in individuals with certain conditions, such as enlarged prostate or cognitive impairment. These medications, when given at higher than recommended doses or in the presence of certain conditions may lead to adverse effects, decompensation or worse.
When reviewing a client’s medications, consider the following ten questions, taken from the Medication Appropriateness Index (MAI):
- Is there an indication for the drug?
- Is the medication effective for the condition?
- Is the dosage correct?
- Are the directions correct?
- Are the directions practical?
- Are there clinically significant drug-drug interactions?
- Are there clinically significant drug-disease interactions?
- Is there unnecessary duplication with other drug(s).
- Is the duration of therapy acceptable?
- Is the drug the least expensive alternative compared with others of equal utility?
Senior Care Pharmacists, especially those who are Board Certified Geriatric Pharmacists (CGP) should be considered for referral in clients with suspected medication-related problems. A directory of practitioners is available at www.seniorcarepharmacist.com and at www.ccgp.org. These websites also include information on senior medication use, including free downloadable forms and informational fact sheets.
Advocare Care Management is the preeminent care manager in South Florida. We are advocates for seniors and have access to numerous resources, tools, connections, and advice. We serve all of South Florida including Broward, Miami-Dade, and Palm Beach counties. You can reach us anytime including the weekends, late nights, evenings, and holidays. Contact Advocare Care Management today and see how we can help you.
Reprinted with permission from Aginglife.org. Advocare Care Management makes caring for a loved one much easier.