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Aging and Drugs

By J. Mark Ruscin, PharmD, FCCP, BCPS, Professor and Chair, Department of Pharmacy Practice, Southern Illinois University Edwardsville School of Pharmacy
Sunny A. Linnebur, PharmD, BCPS, BCGP, Professor of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences

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.

Did You Know...

  • Up to half of older people do not take drugs as directed by their doctor.

  • Older people are more susceptible to the effects (and side effects) of many drugs.

Older people tend to take more drugs than younger people because they are more likely to have more than one chronic medical disorder, such as high blood pressure, diabetes, or 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. Among people who are age 65 years or older, 90% take at least 1 drug per week, more than 40% take at least 5 different drugs per week, and 12% take 10 or more drugs per week. Women typically take more drugs than men. Older people who are frail, hospitalized, or in a nursing home take the most drugs. Nursing home residents are prescribed an average of 7 to 8 different drugs to take on a regular basis. Older people also take many nonprescription (over-the-counter, or OTC) drugs. Many OTC drugs are potentially hazardous for older people.

Benefits and Risks of Prescription 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.

  • Vaccines help prevent many infectious diseases (such as influenza and pneumonia) that once killed many older people.

  • Antibiotics are often effective in treating pneumonia and many other serious infections.

  • Drugs to control high blood pressure (antihypertensives) help prevent strokes and heart attacks.

  • Drugs to control blood sugar levels (insulin and other antihyperglycemic drugs) enable millions of people with diabetes to lead normal lives. These drugs also reduce the risk of eye and kidney problems that diabetes can cause.

  • Drugs to control pain and other symptoms enable millions of people with arthritis to continue to function.

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 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:

  • As people age, the amount of water in the body decreases, and the amount of fat tissue increases. Thus, in older people, drugs that dissolve in water reach higher concentrations because there is less water to dilute them, and drugs that dissolve in fat accumulate more because there is relatively more fat tissue to store them (see Drug Distribution).

  • As people age, the kidneys are less able to excrete drugs into urine, and the liver is less able to break down (metabolize) many drugs (see Drug Metabolism). Thus, drugs are less readily removed from the body (see Drug Elimination).

  • Older people usually take more drugs and have more disorders.

  • People who take more drugs have a higher risk of drug interactions.

  • Fewer studies have been done in older people to help identify appropriate doses of drugs.

  • Older people are more likely to have chronic medical disorders that may be worsened by drugs or that may affect how the drugs work.

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 antianxiety drugs or sleep aids to treat insomnia. Some drugs that lower blood pressure 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.

Some Drugs Particularly Likely to Cause Problems in Older People




Alpha adrenergic blockers (such as doxazosin, prazosin, and terazosin)

To treat high blood pressure

These drugs should not be used to treat high blood pressure.

Use of these drugs increases the risk of orthostatic hypotension (sudden decrease in blood pressure when a person stands up)

Alpha-adrenergic agonists (such as clonidine, guanabenz, guanfacine, methyldopa, and reserpine)

To treat high blood pressure

These drugs should usually not be used to treat high blood pressure unless other drugs have been ineffective.

Use of these drugs may cause orthostatic hypotension and an abnormally slow heart rate and may slow brain function.

Methyldopa and reserpine may contribute to depression.

Reserpine can contribute to erectile dysfunction (impotence).

Analgesics (some, such as meperidine and pentazocine)

To relieve pain

Meperidine, an opioid, often causes confusion and can sometimes cause seizures. Like all opioids, it may cause constipation, retention of urine, drowsiness, and confusion. When taken by mouth, meperidine is not very effective.

Pentazocine can cause confusion and hallucinations.

Antiarrhythmic drugs (some, such as amiodarone, disopyramide, dofetilide, dronedarone, flecainide, ibutilide, procainamide, propafenone, quinidine, and sotalol)

To treat abnormal heart rhythms

These drugs usually should not be used to treat atrial fibrillation (an abnormal heart rhythm).

Amiodarone may increase the risk of thyroid disorders, lung disorders, and long QT syndrome (which itself can contribute to serious abnormal heart rhythms).

Disopyramide has strong anticholinergic effects.* It may cause heart failure in older people.

Antidepressants (older ones, such as amitriptyline, clomipramine, doxepin at high doses, imipramine, and trimipramine)

To treat depression

These older antidepressants have strong anticholinergic effects.* They also cause orthostatic hypotension and excessive drowsiness.

Antihistamines (older ones) that have anticholinergic effects (such as brompheniramine, carbinoxamine, chlorpheniramine, clemastine, cyproheptadine, dexbrompheniramine, dexchlorpheniramine, diphenhydramine, doxylamine, hydroxyzine, promethazine, and triprolidine)

To relieve allergy or cold symptoms, or to aid sleep

Many nonprescription (over-the-counter) and prescription antihistamines have strong anticholinergic effects.*

Antihistamines can cause drowsiness and confusion.

Antihistamines are commonly included in cough and cold preparations.

When using these drugs as sleep aids, people may also develop a tolerance to their effects.

Antiparkinson drugs (benztropine and trihexyphenidyl)

To treat Parkinson disease

More effective drugs are available.

Benztropine and trihexyphenidyl have strong anticholinergic effects.*

Antipsychotic drugs (such as chlorpromazine, haloperidol, mesoridazine, thioridazine, thiothixene, risperidone, olanzapine, quetiapine, and aripiprazole) and metoclopramide

To treat loss of contact with reality (psychosis) or, somewhat controversially, to treat behavioral disturbances in people with dementia

Sometimes to treat nausea (generally chlorpromazine or metoclopramide only)

Antipsychotic drugs can cause drowsiness, movement disorders (that resemble Parkinson disease), and uncontrollable facial twitches. Some of these drugs also have anticholinergic effects.* Some other side effects are potentially fatal. Antipsychotic drugs should be used only when a psychotic disorder is present and require that a doctor closely monitors the person.

When given to people with dementia, antipsychotic drugs increase the risk of stroke and death.

Metoclopramide can cause drowsiness and movement disorders (that resemble Parkinson disease).

Barbiturates (such as amobarbital, butabarbital, butalbital, mephobarbital, pentobarbital, phenobarbital, and secobarbital)

To calm, to relieve anxiety, or to aid sleep

People may become dependent on these drugs, the drugs may become ineffective in helping people sleep, and people can overdose by taking even low doses of these drugs.

Benzodiazepines (such as alprazolam, chlordiazepoxide, chlordiazepoxide with amitriptyline, clidinium with chlordiazepoxide, clonazepam, clorazepate, diazepam, estazolam, flurazepam, lorazepam, oxazepam, quazepam, temazepam, and triazolam)

To calm, to relieve anxiety, or to aid sleep

These drugs can cause drowsiness and loss of balance when a person is walking. The risk of falls and fractures is increased as is the risk of motor vehicle accidents.

The effects of some of these drugs last a very long time (often more than several days) in older people.

Certain hypnotic drugs (such as eszopiclone, zaleplon, and zolpidem)

To aid sleep

The side effects of these drugs are similar to those of benzodiazepines. Doctors prefer to use these drugs only for short periods of time.

Chloral hydrate

To aid sleep

People quickly develop a tolerance to chloral hydrate and it stops working as a sleep aid.

This drug has a high risk of overdose.


To treat heart failure or abnormal heart rhythms (arrhythmias)

As people age, the kidneys are less able to excrete digoxin. Large doses of the drug can more easily reach harmful (toxic) levels. Side effects may include loss of appetite, nausea, and confusion.

Dipyridamole (immediate-release)

To reduce the risk of blood clots or to improve blood flow

Dipyridamole frequently causes orthostatic hypotension in older people. It can also increase the risk of bleeding when it is taken with other drugs that make blood less likely to clot, such as aspirin or the anticoagulant warfarin.

Drugs that reduce or stop muscle spasms in the digestive tract (antispasmodic drugs, such as belladonna alkaloids, clidinium/chlordiazepoxide, dicyclomine, hyoscyamine, propantheline, and scopolamine)

To relieve abdominal cramps and pain

These drugs have strong anticholinergic effects* and frequently cause side effects in older people. Their usefulness—especially at the low doses tolerated by older people—is questionable.

Ergot mesylate and isoxsuprine

To dilate blood vessels

These drugs are not effective for people of any age.

Estrogens with or without progestins

To help relieve menopausal symptoms, such as hot flashes, night sweats, and vaginal dryness.

Estrogens increase the risk of breast and uterine (endometrial) cancer and may increase the risk of stroke, heart attack, and dementia in older women. Vaginal estrogen creams seem to be safe and effective in treating vaginal dryness.

Histamine-2 (H2) blockers (such as cimetidine, famotidine, nizatidine, and ranitidine)

To treat heartburn, indigestion, or ulcers

Typical doses of cimetidine may have drug interactions and cause side effects, especially confusion.

To some extent, high doses of famotidine, nizatidine, and ranitidine may cause side effects, especially confusion.

These drugs may worsen memory and thinking problems in people with cognitive impairment.

Insulin given by a sliding scale

To treat diabetes

When given this way, insulin can cause dangerously low blood sugar and is not more effective at controlling diabetes than fixed doses of insulin given with meals.

Laxatives (such as mineral oil)

To treat constipation

When taken by mouth, mineral oil may be accidentally inhaled into the lungs, which can cause lung damage.

Male sex hormones (such as testosterone and methyltestosterone)

For low testosterone levels (called male hypogonadism)

These hormones should be used only if a man's testosterone levels are low and causing significant symptoms. Use of these hormones may contribute to heart disorders and worsen prostate disorders.


To increase appetite and help regain lost weight

Megestrol can cause blood clots and possibly increase the risk of death and is probably not very effective in helping people gain weight.

Muscle relaxants (such as carisoprodol, chlorzoxazone, cyclobenzaprine, metaxalone, methocarbamol, and orphenadrine)

To relieve muscle spasms

Most muscle relaxants have anticholinergic effects.* They also cause drowsiness and weakness and thus increase the risk of falls and fractures. The usefulness of all muscle relaxants at the low doses necessary to avoid side effects in older people is questionable. The risks likely outweigh the benefits.

Nifedipine (immediate release)

To decrease blood pressure

Nifedipine, if taken in immediate-release capsule form, may decrease blood pressure too much, sometimes causing symptoms similar to those of a heart attack (for example, chest pressure and chest pain).


To treat urinary tract infections

With long-term use, nitrofurantoin can cause side effects (such as lung damage). When taken to treat a bladder infection, it may not be effective if kidney function is reduced.

NSAIDs (such as aspirin, diclofenac, diflunisal, etodolac, fenoprofen,ibuprofen, indomethacin, ketoprofen, meclofenamate, mefenamic acid, meloxicam, nabumetone, naproxen, oxaprozin, piroxicam, sulindac, and tolmetin)

COX-2 inhibitors (celecoxib)

To relieve pain and inflammation

Long-term use of NSAIDs may cause peptic ulcer disease, or bleeding from the stomach or intestine unless another drug is also given to protect the stomach. NSAIDs and celecoxib can also worsen kidney function and symptoms of heart failure.

Of all NSAIDs, indomethacin has the most side effects. It can also cause confusion or dizziness.


To decrease blood pressure or to act as a diuretic

In some people, spironolactone contributes to high levels of potassium in the blood.

Sulfonylurea drugs (long-acting ones, such as chlorpropamide and glyburide)

To treat diabetes

The effects of chlorpropamide and glyburide last a long time. In older people, these drugs can cause low blood sugar levels (hypoglycemia) for many hours. Chlorpropamide can also cause the kidneys to retain too much water, lowering the sodium level in the blood.


To help prevent strokes

Ticlopidine can cause serious blood disorders. Safer and more effective drugs are available.


To relieve nausea

Trimethobenzamide can cause abnormal movements of the arms, legs, and other parts of the body. It is one of the least effective drugs for relieving nausea.

*Anticholinergic effects include confusion, blurred vision, constipation, dry mouth, light-headedness and loss of balance, and difficulty starting to urinate.

Dipyridamole is also available in an extended-release formulation with aspirin. This product, which is used to prevent strokes in people who have had a stroke, is not included in this list.

COX-2 inhibitors = coxibs; NSAIDs = nonsteroidal anti-inflammatory drugs.

Many commonly used drugs have anticholinergic effects. These drugs include some antidepressants (amitriptyline and imipramine), many antihistamines (such as diphenhydramine, contained in OTC 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

  • A disorder, symptom, or condition other than the one for which the drug is being taken (drug–disease interaction)

  • Another drug (drug–drug interaction)

  • Food (drug–food interaction)

  • A medicinal herb (drug–medicinal herb interaction—see Table: Some Possible Medicinal Herb–Drug Interactions)

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

Disorder or Symptom


Chronic kidney disease

NSAIDs (such as ibuprofen and naproxen), triamterene



Drugs with anticholinergic effects*


Delirium, dementia, or mild cognitive impairment



Drugs with sedative effects (such as benzodiazepines, sedatives, and sleep aids) or anticholinergic effects*

Histamine-2 blockers



Fainting or orthostatic hypotension (sudden decrease in blood pressure when a person stands up)

Chlorpromazine, donepezil, doxazosin, galantamine, olanzapine, prazosin, some older antidepressants (such as amitriptyline and imipramine), rivastigmine, terazosin, thioridazine

Use of more than one antihypertensive drug


Drugs with sedative effects (such as antiepileptic drugs, antipsychotics, benzodiazepines, eszopiclone, zaleplon, and zolpidem), antidepressants, and some antihypertensive drugs when used at high doses

Heart failure

Cilostazol, diltiazem, disopyramide, dronedarone, NSAIDs and COX-2 inhibitors, pioglitazone, rosiglitazone, verapamil


Caffeine, oral decongestants (such as pseudoephedrine and phenylephrine), stimulants (such as amphetamine, methylphenidate, and pemoline), theophylline

Parkinson disease

Certain antinausea drugs (metoclopramide, prochlorperazine, promethazine) and most antipsychotics except a few such as quetiapine and clozapine

Peptic ulcer disease or stomach bleeding

Aspirin and most NSAIDs

Seizure disorders

Bupropion, chlorpromazine, clozapine, maprotiline, meperidine, olanzapine, thioridazine, thiothixene, tramadol

Urinary incontinence

Doxazosin, estrogens taken by mouth or through the skin (not applied directly to the vagina), prazosin, terazosin

Urinary retention or urinary symptoms caused by an enlarged prostate (such as slow urinary flow, frequent urination of smaller amounts, and dribbling)

Drugs with anticholinergic effects*, cold remedies containing decongestants

Inhaled anticholinergic drugs used to treat lung disorders (aclidinium, ipratropium, and tiotropium)

*Anticholinergic effects include confusion, blurred vision, constipation, dry mouth, light-headedness and loss of balance, and difficulty starting to urinate.

COX-2 inhibitors = coxibs; NSAIDs = nonsteroidal anti-inflammatory drugs.

Patients, doctors, and pharmacists can take steps to reduce the risk of drug–disease and drug–drug interactions. Because OTC 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 noncompliance or nonadherence) can be risky (see Adherence to Drug Treatment). 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.

Remembering to Take Drugs as Prescribed

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 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. 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:

  • Memory aids

  • Drug containers

  • Smartphone apps

Memory aids

Memory aids can help older people remember to take their drugs. For example, taking a drug can be associated with a specific daily task, such as eating a meal.

Drug containers

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, flash, or talk at dosing time.

Smartphone apps (cell phone apps)

Apps that help people manage their drugs can be downloaded to multiple smartphones and tablets. These apps can help older people or their family members remember to take their drugs on time. Many of these apps include reminder alerts, which are sent to the device. Some of these apps may cost money.

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