Most older people are taking several medications for the treatment of chronic illnesses. More and more often, drugs are also used to prevent many diseases of older adults. People 65 years old and older are prescribed drugs more frequently than any other age group in the United States.
Drug treatment has become much more complex over the past 20 years. New drugs become available every year, and new uses are found for existing drugs. Physicians must keep up to date on these changes and many others, including changes in Medicare payment for drugs and managed care policies about what drugs are available in each plan, scientific advances in understanding drug interactions, changes of many drugs from prescription to over-the-counter, etc.
In addition, there is an evolving boom in a class of medications called nutriceuticals. Nutriceuticals include nutritional supplements, alternative medicines, and herbal preparations that are sold over-the-counter, without the rigorous government review and approval required for prescription drugs (see also Complementary and Alternative Medicine). Very little information is available about the use of nutriceuticals in older adults-and particularly when other medications are being taken.
Changes in Drug Treatment as We Age
For drug treatment to be successful, the correct drug must be administered for the correct condition, for the correct patient, and at the right dose for the right period of time. Unfortunately, this is not always easy. Many factors influence drug treatment. For example, a person may be taking drugs for diseases other than the one currently being treated. This could result in the new drug not working the way it should, or it might set up the possibility of a serious interaction between drugs.
Drug dosages are generally determined by clinical trials done in relatively young, healthy people. These dosages may not be appropriate in older adults because changes associated with age can affect how our bodies deal with drugs, which in turn can affect how the drug works as well as the appropriate dosage. These age-related changes include changes in metabolism and body composition, as well as in the effects of conditions that develop as we age and the medications we take for these conditions.
Bodily changes
To work effectively, drugs must be:
- absorbed into the body (usually through the gut)
- distributed to where they are needed
- metabolized (ie, chemically changed)
Some drugs are first changed to an active form(s) and then to an inactive form that can be eliminated.
- eliminated from the body (usually through the urine)
Bodily changes as we age can affect any of these factors. For example, lean body mass and fluid levels decrease with age, while fat reserves increase. This affects how drugs are distributed. Liver and kidney function decreases with age, which slows down drug metabolism and elimination.
These bodily changes associated with aging can change what constitutes the appropriate dosage for any particular person. When age-related changes decrease absorption or distribution of the drug, a higher dosage may be needed. On the other hand, age-related changes that decrease drug metabolism and elimination may mean that a lower dosage may reach the same effect. An example of the latter is morphine, a narcotic commonly used for severe pain. Morphine has higher blood concentrations and slower elimination in older adults compared with younger adults. Therefore, older adults need only half the dosage of younger people to get the same level of pain relief.
Multiple illnesses
Older adults often have disease conditions that can affect how dugs are absorbed, eliminated, or metabolized. For example, diseases of the gut may decrease drug absorption, so that a larger dosage is required to get the same effect. In contrast, liver or kidney disease may slow down drug elimination, which is why lower dosages are often prescribed for patients with these conditions. Obesity and diseases that cause fluid retention also change drug distribution. Older adults with dementia may have increased sensitivity or unusual reactions to drugs that affect the nervous system.
Food or medications
Drugs can also be affected by food and other medications that are being taken at the same time. For example, some antibiotics (eg, ciprofloxacin) are not absorbed as well when they are taken with things that contain a lot of calcium, magnesium, or iron (eg, antacids, vitamins, or dairy products). Absorption of other antibiotics (eg, amoxicillin) can be increased when taken with antacids.
Some drugs can slow down the metabolism of other medications. For example, fluoxetine (Prozac®) is an antidepressant that is safe and useful in young, healthy adults, but it may not be the best choice for older adults who are taking multiple medications because it can slow down the metabolism of many other drugs. Certain foods, for example, grapefruit juice, can also slow down the metabolism of medications. Other drugs, such as St. Johns wort, can speed up drug metabolism.
Different medications can also interact with each other, sometimes with serious consequences. When drug interactions happen, dosages of a new medicine that are usually correct may be too high or too low. Also, if a new drug interacts and slows down the metabolism of a drug that you are already taking, you may begin to have side effects of the drug that you have been taking all along without having had these problems before.
You should read all prescription labels carefully for warnings on how to take the drug, what it should or should not be taken with, and the potential for drug interactions.
Other factors
Other factors also affect how the body deals with drugs. For example, cigarette smoking, caffeinated or alcoholic beverages, changes in diet, and viral infections seem to affect drug metabolism. There are also differences in drug metabolism between men and women. For example, oxazepam (a drug used for anxiety) is metabolized faster in older men than in older women.
Balancing Drug Treatment
In older adults, drug treatment must be balanced between over-treatment and under-treatment. Over-treatment can result from the use of too many drugs, so that the drugs interact or cause side effects. Over-treatment also refers to use of the wrong medication or the wrong dose. There are numerous causes for over-treatment. Older adults often have multiple chronic diseases for which they are taking multiple medications. Many older adults also see multiple doctors and use multiple pharmacies, so that no one doctor or drug store knows all the drugs that someone is already taking. The consequences of over-treatment include side effects, duplication of drug therapy, decreased quality of life, and unnecessary costs.
Adverse Drug Reactions
Adverse drug reactions include overdoses, side effects, and harmful interactions between drugs. They are among the most serious consequences of inappropriate drug treatment among older adults. Each year, at least 35% of older adults living in the community experience an adverse drug reaction.
Drugs that affect the heart, nervous system, muscles, or bones are most commonly involved in adverse reactions. Not surprisingly, these are the drugs used most commonly in older adults. Other drugs commonly involved in adverse drug reactions are those that are toxic at dosages near the dosage used for treatment. There are also personal characteristics that place certain older adults at greater risk of adverse drug reactions.
Risk Factors for Adverse Drug Reactions in Older Adults
- Having six or more chronic diseases
- Taking twelve or more doses of medication (of any type) per day
- Taking nine or more medications total
- Having had a prior adverse drug reaction
- Being older than 85 years
- Having decreased kidney function
Having multiple risk factors further increases the overall risk of having an adverse drug reaction. However, some signals can indicate when special attention is needed to avoid a drug interaction.
Adverse effects of heart drugs
Heart drugs are a common group of medications that sometimes cause adverse reactions. Digitalis (ie, digoxin) is probably the heart drug most commonly linked to adverse reactions, usually because it may be started at too high a dosage in older people. In older adults, lower dosages of digitalis are generally needed because of bodily changes in water and muscle mass, as well as decreased drug elimination. Overdoses of digitalis typically cause several unpleasant side effects, including nausea, loss of appetite, and mood changes. Fortunately, in most people being treated with digitalis for either mild heart failure or leg swelling, it can be safely withdrawn. Your physician can tell you if any symptoms might be related to taking digitalis, and whether it should be stopped or the dosage adjusted.
Other heart drugs commonly associated with adverse reactions are diuretics (ie, water pills). Diuretics are commonly used for high blood pressure and can cause dehydration and low potassium, sodium, and magnesium in the blood. This may make you feel weak, tired, and run down. It helps to drink plenty of fluids (at least eight glasses a day). You should have your blood checked at regular intervals.
The drugs sometimes prescribed to prevent irregular heartbeats can also cause problems. Because these antiarrhythmics are toxic at dosages near the dosage used for treatment, careful dosing and monitoring of blood levels are required. Side effects include drowsiness, slurred speech, confusion, and numbness and tingling in the arms and legs. Not all antiarrhythmic drugs cause these problems, but the chance of side effects is high enough that you should always check with your healthcare provider if something doesn't feel right to you.
Adverse effects of drugs used for depression and anxiety
Drug treatment for depression or anxiety can also cause adverse reactions as we get older. Some antidepressants can make you sleepy and increase your risk of a drop in blood pressure or other side effects, such as having difficulty urinating, problems with heart rhythm, or confusion. Some anti-anxiety drugs (eg, benzodiazepines) might result in a lack of coordination or other movement problems among older adults.
Adverse effects of pain relievers
Older adults use pain relievers more frequently than any other age group. Many pain relievers (eg, aspirin or ibuprofen) can cause stomach upset, which can be decreased by taking the pills with meals and by drinking plenty of fluids. Although acetaminophen is metabolized and eliminated from the body more slowly in older adults, dosage adjustments are not usually necessary. Pain relievers that are narcotics can cause constipation, which may require the use of stool softeners or enemas (see also Palliative Care - Hospice).
Adverse effects of blood thinners (anticoagulants)
Common blood thinners are warfarin, coumadin, heparin, and aspirin. These drugs are used to slow the coagulation of blood, to prevent clots from forming in the blood vessels and causing heart attacks or strokes. However, this slower clotting means that scrapes, cuts, nose bleeds, surgery, and internal injuries can bleed for a longer time than usual. A fairly common side effect of long-term administration of blood thinners is a bleeding stomach ulcer. These drugs should be used cautiously in people who have ulcers, tend to heal slowly (eg, hemophiliacs and diabetics), or have an increased risk of falling. Aspirin is not a good first-choice pain reliever in people already taking other anticoagulants. The metabolism of most anticoagulants does not change as we age, so changing the dosage is not usually needed.
Confusion caused by drugs
An episode of sudden confusion, called delirium, is often due to medications. Medications such as narcotics, antidepressants, antipsychotic agents, drugs used to relieve intestinal spasms, as well as many nonprescription drugs (eg, antihistamines) can affect the nervous system and contribute to confusion. People with Alzheimer's disease are especially susceptible. These drugs may also cause more subtle changes, such as a decreased ability to take care of oneself by causing subtle declines in mental function.
Ways to Prevent Over-Treatment
The key to preventing drug interactions and over-treatment (ie, too many drugs or inappropriate ones) is communication. You and your doctor should review all medications that you are taking on a regular basis. This includes medications that other healthcare providers have prescribed, as well as over-the-counter drugs, vitamins, nutritional supplements, and herbal remedies. This can help your doctor adjust your treatment plan to avoid over-treatment. Your doctor can also record all medications in your records, so that hospitals and specialists will have a good idea of your current treatment plan if the situation arises.
If you start seeing a new doctor, it is a good idea to get a copy of your records from your old doctor and take them with you. It is also a good idea to put all the medications you are taking (including over-the-counter drugs, vitamins, etc) in a bag and take them to your first visit. This "brown-bag" inventory lets the doctor see exactly what you are taking so that any expired, unnecessary, or inappropriate medications can be discontinued, and so that he or she can ask you about any potential side effects or problems.
Your pharmacist can also explain the potential for drug interactions and provide advice on how to take each drug. It is best if you use the same pharmacy for all prescriptions, so that the pharmacist has a record of everything that has been prescribed for you. Some drug-store chains also maintain a computer record of all prescription sales, so that any store in the chain has a full record of all your prescription purchases at any of their other stores throughout the country.
Non-Adherence
Drugs work effectively only if they are taken as directed for the full schedule of treatment. Failure to do this is termed "non-adherence." Non-adherence is often an unrecognized problem that contributes substantially to under-treatment. It is also common, with estimates of non-adherence among older adults as high as 50%.
People stop taking their medications or take them incorrectly for a variety of reasons. Older adults often have some vision and hearing loss, which can make it difficult for them to understand verbal or written instructions. They may also be hesitant to ask questions or to admit that they don't understand. However, there is no place for embarrassment or shame in learning how to take your medications properly. Ask questions until you are sure that you understand how the medication should be taken. Ask the doctor or pharmacist to provide written instructions so that you can refer to them later.
Some older people may have a mental condition that makes it difficult to understand directions or to remember to take medications. In these instances, extra care is needed in giving directions and making sure that they are understood. Caregivers are important partners in making sure that drugs are taken correctly. A family member or other caregiver can discuss the medications with the doctor and then explain them to the older patient. In addition, using a simple aid can help you and your caregivers make the process simpler and remind you to take your medications. These aids include medication trays, pill organizers, drug calendars, and various timers and other reminders. Your healthcare provider and pharmacist can help set up a process that works for you.
Some older adults also have conditions (eg, arthritis) that make it difficult to open containers or pour liquid medications. Pill aids and easy-open containers are available that may help with these problems. Discuss these issues with your healthcare providers and pharmacist.
Sometimes, older adults do not take their medications because of cost. Prescription drug costs have increased substantially over the years, and many are very expensive. In addition, supplemental drug benefit plans are often expensive and may still leave a person with a co-payment that he or she cannot afford. In these situations, ask your physician or pharmacist if there is a lower-cost medication (eg, an older or generic product) that can be used.
Making Sure You Understand Your Drug Treatment
- Whenever a new drug is prescribed or your dosage is changed, ask about possible side effects. Also ask whether there are any possible interactions with other medications you are taking and, if so, ask what symptoms indicate that the interaction is becoming a problem and you should see your healthcare provider.
- Ask about follow-up and monitoring. For example, when you should see your healthcare provider to make sure that the new medication is working?
- Ask your healthcare provider to review all of your medications on a regular basis, probably once or twice a year, and to let you know which ones are still needed.
- If you have a problem with a medication(s), for example, if you are concerned that a medication is not working or is causing side effects, be sure to tell your healthcare provider and to work with him or her to address the problem.
- Tell your healthcare provider if you cannot afford to keep taking a medication(s). Do not be afraid to ask how much medications are likely to cost. Ask if there is a less expensive or generic medication that would be an acceptable alternative.
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