Polypharmacy, the prescribing of multiple drugs for an individual patient, is most common in older adults, who tend to have more illnesses for which medications are prescribed. Adults aged 65 years and older represent 12% of the population but consume 30% of all prescription medications. Among persons older than age 65 years, the rate of nonprescription (over-the-counter) drug use is seven times that of the general population. The incidence of adverse drug reactions increases with advancing age and the number of drugs taken. Deteriorating vision and cognitive function cause older adults to make many mistakes when taking medications, often with serious consequences. Up to 10% of all hospital admissions for patients over 65 years of age involve medication toxicity.
Clinicians contribute significantly to the problem if they prescribe medications without considering changes in drug metabolism that occur with aging. Renal and hepatic function decrease with advancing age, slowing the clearance of medications. Increases in the proportion of body fat and decreases in the proportion of body water that occur with aging lead to an accumulation of fat-soluble medications in adipose tissue and increases in the concentration of hydrophilic medications in the blood.
Polypharmacy can occur in younger patients as well. As the number of symptoms and diseases increases in an individual, so does the risk of polypharmacy and the attendant risk of overmedication and adverse effects.
While elderly people (those over 65 years of age) form a relatively small percentage of the entire American population, they represent approximately 33% of prescription drug, and 40% of over-the-counter (OTC) drug consumers. Studies show that those 65 and older fill, on average, between 12 - 17 prescriptions per year. Furthermore, the percentage of the population that is over 65 is growing and will increase dramatically over the next 5 - 10 years.
Polypharmacy (taking several medications at the same time) has, in recent years, become the subject of close observation, particularly in elderly people - most of whom are taking more than 1 drug at a time. Studies show that in many cases, elderly people are taking more medication than they need or were prescribed, and/or are taking medications that react negatively with each other, resulting in higher medical bills, ineffective treatment and serious drug-related illnesses.
Sometimes people begin to take medications (without telling their physicians) that were prescribed for them months earlier, and which they did not finish and have left over in their medicine cabinet. These medications may have a serious drug interaction with a medication that was recently prescribed. While someone may need a number of different medications to control co-existing conditions like high blood pressure, heart disease and diabetes, polypharmacy in the elderly can have serious consequences - as shown by the observation that 10% of emergency hospital admissions are from elderly people having negative reactions to their medications.
In many cases polypharmacy occurs because elderly people often see more than 1 doctor. Each doctor they see may prescribe medications for treatment without knowing the person's drug history, and because they don't know the history, they may be prescribing inappropriate medications.
These problems result from a variety of factors, including the physician's failure to ask enough questions and the patient's lack of understanding that their drug regimen may need to be monitored for dangerous interactions.
It is important to note that the communication breakdown between doctor and patient can be influenced by external factors. Many doctors, for example, are so overbooked that they simply don't have the time to perform examinations and review a patient's drug history. At the same time, many elderly people are unable to access a primary care physician - one "main" doctor who is able to keep track of their history, including their medications and visits to specialist physicians. In addition, many people are intimidated by doctors, and this results in unasked questions and unvoiced concerns. Patients should either bring all the medications they are taking with them every time they see a physician or should bring a printed list of these medications.
In clinical terms, an adverse drug reaction means that the drug taken causes an undesired effect. ADRs in elderly polypharmacy are mainly caused by multiple drugs reacting with each other (leading to conflicting or ineffective results). ADRs can also cause allergic reactions and/or side effects such as confusion and unsteadiness (both of which can lead to falls), depression and irregular heart beat. ADRs can be difficult to diagnose since the side effects can mimic the symptoms of aging or an existing illness.
Since the body changes as it ages, older people respond differently to medications than younger people - drugs tend to be much harder on older systems. For example, many medications are processed by the kidneys, yet natural aging can decrease kidney function by 40 - 50%. With polypharmacy, the elderly person's kidneys may not be able to process all of the medications running through the body, leading to strained kidneys as well as a "build up" of drugs which can result in drug toxicity.
Even though an individual may need to take medications to treat illnesses like diabetes and high blood pressure, these conditions may lower the elderly person¹s ability to absorb and process medications resulting again in a "build up" of drugs in the body causing drug toxicity.
Following a drug regimen (compliance) can be incredibly difficult since certain drugs need to be taken at certain times, or more than once a day or with food or after meals. The more medications a person is required to take, the more likely they are to forget to take them. Compliance can be particularly difficult in elderly people who may have vision problems (they may not be able to read labels properly or distinguish between pills, for example) or may already be suffering from confusion as a result of adverse drug reactions.
If you are caring for an elderly person, being aware of polypharmacy and its complications can go a long way to preventing medication-related complications. You can also help your care recipient by suggesting (or doing) the following: