Aging and Drugs

Many of the improvements in the health and function of older people during the past several decades can be attributed to the benefits of drugs.

However, drugs can have effects that are not intended or desired (side effects). Starting in late middle age, the risk of side effects related to the use of drugs increases. Older people are more than twice as susceptible to the side effects of drugs Overview of Adverse Drug Reactions Adverse drug reactions (adverse effects) are any unwanted effects of a drug. In the early 1900s, German scientist Paul Ehrlich described an ideal drug as a "magic bullet." Such a drug would... read more as younger people. 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 the side effects of drugs 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 sometimes 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 a greater risk of 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 certain antianxiety drugs (see table Drugs Used to Treat Anxiety Disorders Drugs Used to Treat Anxiety Disorders ) or sleep aids to treat insomnia Treatment The most commonly reported sleep-related problems are insomnia and excessive daytime sleepiness. Insomnia is difficulty falling asleep or staying asleep, waking up early, or a disturbance in... read more . Some drugs that lower blood pressure Drug Treatment of High Blood Pressure High blood pressure is very common. It often does not cause symptoms; however, high blood pressure can increase the risk of stroke, heart attacks, and heart failure. Therefore, it is important... read more tend to lower blood pressure much more dramatically in older people than in younger people. Larger decreases in blood pressure can lead to side effects such as dizziness, light-headedness, and falls. Older people who have such side effects should discuss them with their doctor.

Many commonly used drugs have anticholinergic effects Anticholinergic: What Does It Mean? . These drugs include some antidepressants (amitriptyline and imipramine), many antihistamines (such as diphenhydramine, contained in over-the-counter sleep aids, cold remedies, and allergy drugs), and many antipsychotics (such as chlorpromazine and clozapine). Older people, particularly those with memory impairment, are particularly susceptible to anticholinergic effects, which include confusion, blurred vision, constipation, dry mouth, and difficulty starting to urinate. Some anticholinergic effects, such as reduction of tremor (as in the treatment of Parkinson 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. In many drug-disease interactions, taking a dug can worsen a disorder, symptom, or condition (see table Some Disorders and Symptoms That Can Be Worsened by Drugs in Older People Some Disorders and Symptoms That Can Be Worsened by Drugs in Older People ).

Patients, doctors, and pharmacists can take steps to reduce the risk of drug–disease and drug–drug interactions. Because over-the-counter drugs and medicinal herbs can interact with other drugs, people should ask their doctor or pharmacist about combining the use of these drugs with prescription drugs.

Not following a doctor’s directions for taking a drug (called nonadherence) can be risky (see Adherence to Drug Treatment Adherence to Drug Treatment Adherence is the degree to which a person takes prescribed drugs as directed. (See also Overview of Response to Drugs.) Adherence to (compliance with) drug treatment is important. However, only... read more ). Older age alone does not make people less likely to take drugs as directed. However, up to half of older people do not take drugs as directed. 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.

Older people and the people who care for them can do many things to maximize the benefits and reduce the risks of taking drugs. Any questions about or problems with a drug should be discussed with a doctor or pharmacist. Taking drugs as instructed and communicating with health care providers is essential for avoiding problems and promoting good health.

Know about the drugs and disorders being treated:

Use drugs correctly:

Work closely with the doctor and pharmacist:

To benefit from taking drugs, people must remember not only to take their 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. For example, bisphosphonates (such as alendronate, risedronate, and ibandronate), 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. Also, over time, some drugs may not be needed any longer and can be stopped.

The following things can help people remember to take their drugs as prescribed:

The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.