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Aging and Drugs

By

J. Mark Ruscin

, PharmD, FCCP, BCPS, Southern Illinois University Edwardsville School of Pharmacy;


Sunny A. Linnebur

, PharmD, BCPS, BCGP, University of Colorado Anschutz Medical Campus

Last full review/revision Dec 2018| Content last modified Dec 2018
Click here for the Professional Version
Topic Resources

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. Almost 90% of older adults regularly take at least 1 prescription drug, almost 80% regularly take at least 2 prescription drugs, and 36% regularly take at least 5 different prescription drugs. When over-the-counter and dietary supplements are included, these rates are even higher. 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 (see Precautions With Over-the-Counter Drugs: 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 serious infections, including pneumonia.

  • 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 total 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 certain antianxiety drugs (see table Drugs Used to Treat Anxiety Disorders) 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.

Table
icon

Some Drugs Particularly Likely to Cause Problems in Older People

Drug

Use

Problem

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

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).

These drugs can make it hard for women to hold their urine.

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

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.

Amiodarone

Amiodarone usually should not be a first choice to treat atrial fibrillation (an abnormal heart rhythm) except in special circumstances.

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

Antidepressants (older ones, such as amitriptyline, amoxapine, clomipramine, desipramine, doxepin at high doses, imipramine, nortriptyline, paroxetine, protriptyline, and trimipramine)

To treat depression

These older antidepressants have strong anticholinergic effects.* They also increase risk of falls, constipation, dry mouth, excessive drowsiness, and abnormal heart rhythms.

Antihistamines (older ones) that have anticholinergic effects* (such as brompheniramine, carbinoxamine, chlorpheniramine, clemastine, cyproheptadine, dexbrompheniramine, dexchlorpheniramine, dimenhydrinate, diphenhydramine, doxylamine, hydroxyzine, meclizine, 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.*

These antihistamines can cause drowsiness and confusion, and when used regularly, they can also cause constipation, dry mouth, and difficulty urinating.

Antihistamines are commonly included in cough and cold preparations and in pain relievers for use at bedtime.

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

Antiparkinson drugs (benztropine and trihexyphenidyl)

More effective drugs are available.

Benztropine and trihexyphenidyl have strong anticholinergic effects.*

Antipsychotic drugs (such as chlorpromazine, haloperidol, 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). In general, metoclopramide should not be used longer than 3 months.

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 crashes.

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. It is best to use these drugs only for short periods of time.

Desmopressin

To help control nighttime urination

Desmopressin has a high risk of causing hyponatremia (low level of sodium in the blood). Desmopressin should not be used for treatment of excessive urination at night because there are safer alternatives.

To treat heart failure or abnormal heart rhythms(arrhythmias)

As people age, the kidneys are less able to remove digoxin from the body. 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 low blood pressure when standing up 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 atropine [except for eye drops], 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 treat osteoporosis and 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 products seem to be safe and effective to treat painful intercourse, urinary tract infections, and other vaginal symptoms.

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

To treat heartburn (acid reflux), 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.

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.

Megestrol

To increase appetite and help regain lost weight

Megestrol can cause blood clots and possibly increase the risk of death and is typically 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)

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).

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.

Proton-pump inhibitors

To reduce stomach acid production and treat acid reflux and ulcers

Long-term use of proton-pump inhibitors increases the risk of severe diarrhea caused by Clostridium difficile infection, bone loss and fractures, and vitamin B12 deficiency.

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.

Ticlopidine

To help prevent strokes

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

*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.

Anticholinergic: What Does It Mean?

Anticholinergic effects are caused by drugs that block the action of acetylcholine. Acetylcholine is a chemical messenger (neurotransmitter) released by a nerve cell to transmit a signal to a neighboring nerve cell or a cell in a muscle or gland. Acetylcholine helps cells talk to each other. Acetylcholine helps with memory, learning, and concentration. It also helps control the functioning of the heart, blood vessels, airways, and urinary and digestive organs. Drugs that block the effects of acetylcholine can disrupt the normal functioning of these organs.

Many commonly used drugs have anticholinergic effects. Most of these drugs were not designed to have these unwanted effects. Anticholinergic effects include the following:

  • Confusion

  • Blurred vision

  • Constipation

  • Dry mouth

  • Light-headedness and loss of balance

  • Difficulty urinating

However, anticholinergic drugs can also have useful effects, such as helping control tremors, nausea, or overactive bladder.

Older people are more likely to experience anticholinergic effects because the amount of acetylcholine in the body decreases with age. Consequently, anticholinergic drugs block a higher percentage of acetylcholine, so that the aging body is less able to use what little acetylcholine is present. Also, cells in many parts of the body (such as the digestive tract) have fewer sites where acetylcholine can attach. As a result, doctors usually try to avoid using drugs with anticholinergic effects in older people if possible.

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).

Table
icon

Some Disorders and Symptoms That Can Be Worsened by Drugs in Older People

Disorder or Symptom

Drugs

NSAIDs (such as ibuprofen and naproxen)

Delirium, dementia, or mild cognitive impairment

Chlorpromazine

Corticosteroids

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

Histamine-2 blockers (cimetidine, famotidine, nizatidine, ranitidine)

Meperidine

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 (or too much of one antihypertensive)

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

Cilostazol, diltiazem, disopyramide, dronedarone (in patients with severe heart failure), NSAIDs and COX-2 inhibitors, pioglitazone, rosiglitazone, verapamil

Caffeine, oral decongestants (such as pseudoephedrine and phenylephrine), stimulants (such as armodafinil, amphetamine, methylphenidate, and modafinil), theophylline, selegiline

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

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

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, or a combination of antihistamines and decongestants

*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 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.

Maximizing the Benefits and Reducing the Risks of Taking Drugs

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:

  • Keep a list of all medical problems and drug allergies.

  • Keep a list of all drugs being taken, including over-the-counter drugs and supplements, such as vitamins, minerals, and medicinal herbs.

  • Learn why each drug is taken and what its benefits are supposed to be.

  • Learn what side effects each drug may have and what to do if a side effect occurs.

  • Learn how to take each drug, including what time of day it should be taken, whether it can be taken with food, or 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).

Use drugs correctly:

  • Take drugs as instructed.

  • Use memory aids, such as a medication organizer, to take drugs as instructed.

  • Before stopping a drug, consult the doctor about any problems—for example, if side effects occur, if the drug does not seem to work, or if the cost of the drug is burdensome.

  • Discard any unused drug from a previous prescription, unless instructed not to do so by a doctor, nurse, or pharmacist.

  • When discarding a drug, follow the disposal instructions on the label, review the information at the Food and Drug Administration's web site, take drugs to an authorized disposal center (possibly at a pharmacy or local law enforcement site), or mix the drug with kitty litter or coffee grounds, tightly wrap in plastic or a similar material, place in a sealable or watertight container or bag, and discard in the trash.

  • Do not take another person’s drug, even if that person’s problem seems similar.

  • Check the expiration date on drugs, and do not use the drug if it has expired.

Work closely with the doctor and pharmacist:

  • 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.

  • Bring all drugs being taken to medical appointments if requested to do so.

  • Periodically discuss the list of drugs being taken and the list of disorders with the doctor, nurse, or pharmacist to make sure the drugs are correct and should be continued. For example, people can test themselves by telling their health care providers how they are supposed to take all drugs and asking whether what they have said is correct.

  • Review the list of drugs with the doctor, nurse, or pharmacist every time a drug is changed (doctors and pharmacists can check for interactions between drugs).

  • Make sure the doctor and pharmacist know about all over-the-counter drugs and supplements being taken, including vitamins, minerals, and medicinal herbs.

  • Consult the doctor before taking any new drugs, including over-the-counter drugs and supplements.

  • Report to the doctor or pharmacist any symptoms that might be related to the use of a drug (such as new or unexpected symptoms).

  • If the schedule of taking drugs is too complex to follow, ask the doctor or pharmacist about simplifying it.

  • If seeing more than one doctor, make sure each doctor knows all the drugs being taken.

  • 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.

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. 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:

  • 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. Additionally, many pharmacies can adjust refill schedules so that regularly used drugs are picked up on a single day each month. This decreases confusion, helps reduce trips to the pharmacy, and minimizes mistakes filling pill organizers.

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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