Aging & Health A to Z
Basic Facts & Information
People 65 years old and older take prescribed medications more frequently than any other age group in the United States. Most older adults take several medicines to treat chronic illnesses. Health care providers may also prescribe medications to older adults to help prevent certain illnesses.
Medications Work Differently in Older Adults
Medication dosages are generally determined by clinical trials done in relatively young, healthy people. These dosages may not be appropriate for older adults, because changes can occur with age that can affect how our bodies deal with drugs.
Changes in metabolism and body composition as we age can affect how well a medication works. These changes can also affect the appropriate dosage of the medication. Both the effectiveness and dosage of medications can be affected by diseases and conditions that develop later in life, and the medicines we take for them.
For example, liver and kidney function decrease with age. This can slow down the metabolism of a medication and its elimination from the body. What’s more, weight gain often occurs as we age and muscle mass decreases. This affects how your body distributes medication to its different parts.
Changes in the Body
To work effectively, medications must be:
- Absorbed into the body (usually through the stomach and intestines)
- Distributed to where they are needed
- Metabolized (chemically changed to become effective or to be eliminated from the body)
- Eliminated from the body (usually through the urine)
These age-related changes can affect the appropriate dosage, depending on the person. When these changes decrease absorption or distribution of the medicine, a higher dose may be needed. On the other hand, changes that decrease its metabolism and elimination may mean that you’ll need a lower dose.
When taking medications, these factors will make sure you have the best outcome:
- When the correct medication is prescribed for the correct condition.
- When the medication is right for you and your condition.
- When you take the proper dose for the length of time your healthcare provider recommends.
Unfortunately, these guidelines are not always black and white. Many factors influence medication treatment. For example, a person may be on medicines for other conditions, in addition to the new one just prescribed. This could result in the new medication not working the way it should, or there may be an interaction between the medications.
Multiple Medical Conditions
Older adults often have multiple medical conditions. These may affect how medications are absorbed, metabolized, or eliminated. Obesity and diseases that cause fluid retention also change how your body responds to certain medicines. Older adults with memory problems may have increased sensitivity or unusual reactions to certain medications.
Effects of Food and Beverages on Medications
Medications may be affected by food, beverages, and other medications that you take at the same time. For example, some antibiotics are not absorbed well when taken with foods, beverages or other medications that contain a lot of calcium, magnesium, or iron (such as antacids, vitamins, or dairy products). Certain foods, such as grapefruit juice, can also change the metabolism of medications. This makes the medicine build up in the body.
Some medications can slow down the metabolism of other medications. Others can speed up the process. Different medications may interact with each other, sometimes with serious consequences. Usually, there is a correct dose for a new medication that you are prescribed. However, medication interactions can cause the dose of a new medicine to be too high or too low. If a new medication interacts and slows down the metabolism of a medication that you are already taking, you may begin to have side effects that are new to you.
Read all prescription and warning labels carefully. You will find the following information:
- Instructions on how to take the medication
- what it should or should not be taken with
- the potential for medication interactions
Other factors may affect how the body deals with medications. For example, medication metabolism seems to be affected by cigarette smoking, drinking caffeinated or alcoholic beverages, changes in diet, and viral infections.
Many older adults cope with more than one medical condition at the same time. Often, managing these medical conditions can mean that you may need many different medications.
When older adults take five or more medicines, it is called “polypharmacy.” With polypharmacy, the medicines can interact with each other and with your body in harmful ways. For example, the medications can increase negative side effects or decrease desired effects.
An example of a negative side effect is frailty, which is a problem linked to aging. Someone who is frail can be weak, have less endurance, and be less able to function well. Frailty increases the risk for falls, disability, and even death. In addition to frailty, the risk for falls and delirium also increases when you take multiple medications.
In a recent study published in the Journal of the American Geriatrics Society, older adults who took more than 10 medications were twice as likely to become frail within three years as people who took less than five medications. Reducing the number of medications prescribed could be a promising approach for lessening the risks for frailty for older adults.
Primary care providers know about the negative effects that taking multiple medications can cause. But unless you tell them about all the medicines you’re taking, they may not realize what’s causing your problem. Tell all your healthcare providers about all of the prescriptions you are taking, no matter which provider prescribed them to you. Be sure to mention any drugstore supplements or other medications you take on your own.
Tell your healthcare provider about all the medicines that you are taking. (If you are caring for an older adult, you will want to do the same with their healthcare providers.) Discuss vitamins, supplements, and other over the counter medications, as well as any prescribed by other healthcare providers. Then you and your provider can figure out whether one or more drugs might be changed or stopped.
Sometimes, one of the medications you’re taking may cause new symptoms, or make symptoms you already have get worse. This could potentially lead to what is called a “prescribing cascade.” This is when a side effect of a medication is mistaken for a new medical condition, so your healthcare provider uses a new medicine to treat the side effect of the other medication. This can lead to being prescribed even more medications and having even more side effects. Therefore, it is very important that your healthcare provider review all of your medications and consider their side effects before prescribing any new medications.
The Commission for Certification in Geriatric Pharmacy says that for older adults, “Any new symptom should be considered a drug side effect until proven otherwise.”
Updated: January 2018
Posted: March 2012