Drugs, the most common medical intervention, are an important part of medical care for older people. Without drugs, many older people would function less well or die at an earlier age.
Older people tend to take more drugs than younger people because they are more likely to have chronic disorders such as high blood pressure, diabetes, and arthritis. Most drugs used by older people for chronic disorders are taken for years. Other drugs may be taken for only a short time to treat such problems as infections, some kinds of pain, and constipation. On average, older people take four or five prescription drugs and two nonprescription (over-the-counter, or OTC) drugs each day. Many OTC drugs are potentially hazardous for older people (see Over-the-Counter Drugs: Older People).
Benefits and Risks
Many of the improvements in the health and function of older people during the past several decades can be attributed to drugs.
However, drugs can have effects that are not intended or desired (side effects). Starting in late middle age, the risk of side effects from drugs increases. Older people are more than twice as susceptible to the side effects of drugs as younger people (see Adverse Drug Reactions: Overview of Adverse Drug Reactions). Side effects are also likely to be more severe, affecting quality of life and resulting in visits to the doctor and in hospitalization.
Older people are more susceptible to side effects for several reasons:
Because of these age-related changes, many drugs tend to stay in an older person's body much longer, prolonging the drug's effect and increasing the risk of side effects. Therefore, older people often need to take smaller doses of certain drugs or perhaps fewer daily doses. For example, digoxin, a drug commonly used to treat certain heart disorders, dissolves in water and is eliminated by the kidneys. Because the amount of water in the body decreases and the kidneys function less well as people age, digoxin concentrations in the body may be increased, resulting in side effects (such as nausea or abnormal heart rhythms). To prevent this problem, doctors may use a smaller dose. Or sometimes other drugs can be substituted.
Older people are more sensitive to the effects of many drugs. For example, older people tend to become sleepier and are more likely to become confused when using antianxiety drugs or sleep aids to treat insomnia. Drugs that lower blood pressure by widening (dilating) arteries and reducing the amount of work the heart has to do tend to lower blood pressure much more dramatically in older people than in the young. Knowing which drugs are particularly likely to cause problems in older people helps avoid side effects, such as dizziness, light-headedness, and falls. Older people who are taking these drugs can ask their doctor about changing to a different drug.
Many commonly used drugs have anticholinergic effects. These drugs include some antidepressants, many antihistamines (contained in OTC sleep aids, cold remedies, and allergy drugs), and diphenhydramine (used in the treatment of insomnia). Older people are particularly susceptible to anticholinergic effects, which include confusion, blurred vision, constipation, dry mouth, light-headedness, difficulty starting and continuing to urinate, and loss of bladder control (urinary incontinence). Some anticholinergic effects, such as reduction of tremor (as in the treatment of Parkinson's disease) and reduction of nausea, are desirable, but most are not.
A drug may have a side effect because it interacts with
Because older people tend to have more diseases and take more drugs than younger people, they are more likely to have drug-disease and drug-drug interactions. Patients, doctors, and pharmacists can take steps to reduce the risk of these interactions (see Factors Affecting Response to Drugs: How to Reduce the Risk of Drug-Drug Interactions). Because OTC drugs and medicinal herbs can interact with other drugs, people should ask their doctor or pharmacist about these drugs as well as about prescription drugs.
Not following a doctor's directions for taking a drug (noncompliance or nonadherence) can be risky (see Adherence to Drug Treatment). Old age alone does not make people less likely to take drugs as directed. However, up to half of older people do not do so. Not taking a drug, taking too little, or taking too much can cause problems. Taking less of a drug because it has side effects may seem reasonable, but people should talk to a doctor before they make any changes in the way they take a drug.
Remembering to Take Drugs
To benefit from taking drugs, people must remember not only to take the drugs but also to take them at the right time and in the right way. When several drugs are taken, the schedule for taking them can be complex. For example, drugs may have to be taken at different times throughout the day to avoid interactions. Some drugs may have to be taken with food. Other drugs have to be taken when no food is in the stomach. The more complex the schedule, the more likely people are to make mistakes following it. For example, bisphosphonates (such as alendronate and risedronate), which are used to increase bone density, need to be taken on an empty stomach and with only water (at least a full glass). If these drugs are taken with other liquids or food, they are not absorbed well and do not work effectively.
If older people have memory problems, following a complex schedule is even harder. Such people usually need help, often from family members. The doctor can be asked about simplifying the schedule. Often, doses can be rescheduled to make taking the drugs more convenient or reduce the total number of daily doses.
Memory aids can help older people remember to take their drugs. For example, using a drug can be associated with a specific daily task, such as eating a meal.
A pharmacist can provide containers that help people take drugs as instructed. Daily doses for 1 week or 2 weeks may be packaged in a plastic pack marked with the days or with the times of the day, so that people can keep track of doses taken by noting the empty spaces. Some pharmacies can package drugs in blister packs, so that the daily dose can be easily removed and kept track of. However, such packaging may cost a little more.
More elaborate containers with a computerized reminder system are available. These containers beep or flash at dosing time. Another alternative is a paging service with a beeper. This service is available from subscriber-based telecommunications companies.
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Last full review/revision February 2009 by J. Mark Ruscin, PharmD