Drugs and Aging

When people get older, they tend to use more drugs. On average, an older person takes four or five prescription drugs plus two nonprescription (over-the-counter) drugs each day.

Most drugs used by older people are taken for years. Such drugs are usually used to control chronic disorders, such as high blood pressure, diabetes, and arthritis. Or these drugs may be used to prevent or relieve symptoms caused by such disorders. Other drugs may be taken for a short time to treat such problems as infections, pain after surgery, and constipation.

Benefits and Risks

Drugs are an important part of medical care for older people. They can prevent, control, or cure disease. They can also control many of the symptoms caused by disease. Without drugs, many older people would die or function less well.

Many of the improvements in the health and function of older people during the past several decades can be attributed to drugs. Vaccines prevent many infectious diseases (such as influenza and pneumonia) that once killed many older people. Antibiotics are effective in treating pneumonia—once known as the killer of older people—and many other serious infections. Drugs to control high blood pressure help prevent strokes and heart attacks. Drugs to control blood sugar levels enable millions of people with diabetes to lead normal lives. Drugs to control pain and other symptoms enable millions of people with arthritis to continue to function.

On the other hand, drugs can have effects that are not intended or desired (side effects). Some side effects are merely bothersome. But others are harmful. Starting in late middle age, the risk of having side effects from drugs increases. Older people are more than twice as likely to have side effects from drugs than younger people are. Furthermore, in older people, side effects are more likely to be severe, to worsen the quality of life, and to require visits to the doctor or hospital stays.

Certain drugs and types of drugs are particularly likely to cause problems in older people. Such a drug can often be replaced with a safer drug that is just as effective. For example, the effects of some drugs used to treat insomnia or anxiety, such as chlordiazepoxide, diazepam, and flurazepam, last too long. As a result, these drugs may make older people become unsteady or confused. The effects of other drugs used to treat insomnia or anxiety, such as lorazepam, oxazepam, and temazepam, usually do not last as long. Thus, these drugs are less likely to make older people unsteady or confused. Knowing which drugs are particularly likely to cause problems in older people helps avoid side effects. Older people who are taking these drugs can ask their doctor about changing to a different drug.

Reasons for Increased Risk

Drugs are more likely to cause problems in older people for three main reasons. The aging body processes drugs differently, certain drugs affect the aging body differently, and older people take more drugs and have more disorders.

How the aging body processes drugs: Changes due to aging itself affect how the body processes drugs. For example, the amount of water in the body decreases and the percentage of body fat increases. These changes are important because some drugs dissolve in water and others dissolve in fat. Drugs that dissolve in fat tend to accumulate in the body because there is relatively more fat to store them.

Changes in the kidneys and liver also affect how the aging body processes drugs. The liver chemically alters (metabolizes) many drugs. It activates some drugs, inactivates others, and prepares many drugs to be eliminated from the body. Most drugs are eliminated from the body by the kidneys in urine. As people age, the liver is less able to alter certain drugs, and the kidneys are less able to eliminate drugs.

All of these changes tend to make certain drugs (but not all) stay in an older person's body much longer than they would in a younger person's body. As a result, the drug's effects continue for a longer time and may be stronger. The risk of side effects may also increase. For these reasons, older people often need to take smaller doses of certain drugs or sometimes fewer doses a day.

How drugs affect the aging body: As people age, the body changes in ways that affect how the body responds to drugs. As a result, older people are more sensitive to many drugs and less sensitive to a few. A drug's intended effect may be stronger. For example, sleep aids may make older people sleepier and more likely to become confused than they would younger people. Some drugs that lower blood pressure tend to lower the pressure much more dramatically in older people than in younger people. Increased sensitivity to a drug's effects also means that side effects are more likely to occur and that they may be more severe.

Older people are particularly sensitive to a group of drugs that have anticholinergic effects. Anticholinergic effects include confusion, blurred vision, constipation, dry mouth, light-headedness, difficulty starting and continuing to urinate, and loss of bladder control (urinary incontinence). Sometimes anticholinergic effects are desirable. For example, one anticholinergic effect is to make the bladder less active. Drugs with this effect can be used to treat certain types of incontinence. When anticholinergic effects are undesirable, another drug can sometimes be used instead. If another drug cannot be used, health care practitioners monitor the person for undesirable effects.

Drugs with anticholinergic effects include many commonly used drugs: some antidepressants (used to treat depression), some antipsychotic drugs (used to treat loss of contact with reality, or psychosis), and many antihistamines (contained in nonprescription sleep aids, cold remedies, and allergy drugs).

More drugs, more disorders: The more drugs taken, the more likely drug interactions are to occur. Drug interactions are problems that occur because one drug affects another drug or a disorder other than the one being treated. When two or more drugs, including nonprescription drugs, are taken about the same time, one drug can interfere with how the other drug works, leading to side effects. Taking dietary supplements (such as vitamins, minerals, or medicinal herbs) or consuming food about the same time a drug is taken can cause similar problems.

Also when many drugs are taken, the schedule for taking them can be hard to follow. If the schedule is not followed, side effects are more likely to occur or the drugs may be less effective.

When two or more disorders are present, a drug taken to treat one disorder may worsen another disorder. For example, a nonprescription sleep aid that contains diphenhydramine can make urinating more difficult for men who have a prostate disorder. This drug can also worsen vision in people who have glaucoma and worsen confusion in people who have dementia.

See the table Some Drugs Particularly Likely to Cause Problems in Older People.

See the sidebar What Are Anticholinergic Effects?

Maximizing Benefits, Reducing Risks

Older people and the people who care for them can do many things to maximize the benefits and reduce the risks that may result from taking drugs.

Information about the drugs and disorders being treated is vital:

• Learn why each drug is taken and what its effects are supposed to be.
• Learn what side effects each drug may have.
• Learn how to take each drug, including what time of day it should be taken, whether it can be taken at the same time as other drugs, and when to stop taking the drug.
• Learn what to do if a dose is missed.
• Write down information about how to take the drug or ask the doctor, nurse, or pharmacist to write it down (because such information can easily be forgotten).
• Keep a list of all drugs being taken.
• Keep a list of all disorders present.

To work, drugs must be used properly:

• Take drugs as instructed.
• Use memory aids if needed to take drugs as instructed.
• Before stopping a drug, consult the doctor about any problems caused by taking the drug—for example, if side effects occur, if the drug does not seem to work, or if purchasing the drug is burdensome.
• Discard any unused drug from a previous prescription, unless instructed not to do so by a doctor, nurse, or pharmacist.
• Do not take another person's drug, even if that person's problem seems similar.
• Check the expiration date on drugs.

Working closely with a doctor and pharmacist can help:

• Get all prescriptions from the same pharmacy, preferably one that provides comprehensive services (including checking for possible drug interactions) and that maintains a complete drug profile for each person.
• Periodically discuss the list of drugs being taken and the list of disorders with the doctor, nurse, or pharmacist.
• Review the list of drugs with the doctor, nurse, or pharmacist every time any drug is changed (doctors and pharmacists can check for interactions between drugs).
• Make sure the doctor and pharmacist know about all nonprescription drugs and supplements being taken, including vitamins, minerals, and medicinal herbs.
• Consult the doctor before taking any new drugs, including nonprescription drugs and supplements, such as medicinal herbs.
• Report to the doctor or pharmacist any symptoms that might be related to the use of a drug.
• If the schedule of taking drugs is too complex to follow, ask the doctor about simplifying it.
• If seeing more than one doctor, make sure each doctor knows all the drugs being taken.

Drugs should be labeled and packaged in a way that makes them easy to use:

• Ask the pharmacist to print the label in large print and check to make sure it can be read.
• Ask the pharmacist to package the drug in containers that are easy to hold and to open.

Any questions about or problems with a drug should be discussed with the doctor or pharmacist. Taking drugs as instructed is essential for avoiding problems and promoting good health.

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 many 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 a person is to make mistakes following it.

If an older person has memory problems, following a complex schedule is even harder. Such a person usually needs 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 a meal.

A pharmacist can provide containers that help people take drugs as instructed. Daily doses for 1 or 2 weeks may be packaged in a plastic pack marked with the days, so that people can keep track of doses taken by noting the empty spaces. 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.

Nonprescription Drugs

Nonprescription drugs have many beneficial effects in older people and are commonly used. However, the fact that these drugs are nonprescription is no guarantee that they are safe. Some nonprescription (over-the-counter) drugs can cause problems in older people. The package insert of nonprescription drugs typically includes a warning for older people. However, the warnings often do not make a strong enough impression, and the print may be small, making them hard to read. Also, nonprescription drugs, like prescription drugs, may have undesirable side effects as well as benefits.

Antihistamines that have anticholinergic effects (such as diphenhydramine and chlorpheniramine) can cause problems. For example, these antihistamines may worsen some disorders common among older people, such as closed-angle glaucoma and an enlarged prostate gland. They may cause light-headedness or unsteadiness, leading to falls and broken bones. They may also cause dry mouth, blurred vision, constipation, and confusion. Antihistamines are contained in many nighttime pain relief formulas, cough and cold remedies, allergy drugs, and sleep aids. When an antihistamine is needed, one without anticholinergic effects (such as loratadine) is preferable.

Older people who take aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) may develop ulcers and bleeding ulcers. Older people may be more susceptible to side effects of antacids. Antacids that contain aluminum are more likely to cause constipation. Antacids that contain magnesium are more likely to cause diarrhea.