Therapeutics Iii Exam 4 - Lecture 11 (Geriatric Pharmacotherapy Concepts)

Front 1

1. Summarize the epidemiology of aging.

Back 1

The elderly are making up a greater and greater percentage of our population due to immunizations, medical procedures and medications, healthy lifestyles, and better social living conditions. Life expectancy has risen greatly in the past 100 years. The percentage of elderly people living in nursing homes has dropped in this time. Common conditions in the elderly include arthritis, hypertension, heart disease, hearing impairment, cataracts, and diabetes.

Front 2

2. Compare physical, social, and psychological changes in the elderly to younger adults and their implications for drug use, prescribing and monitoring.

Back 2

In the elderly, muscle decreases by 25%. Adipose tissue increases by 25-30%. Total body water decreases by 25%, putting them at greater risk for dehydration. The liver decreases in size and blood flow; this decreases the first pass effect. Elderly people also exhibit decreases in lens accommodation and loss of auditory acuity. They maintain mental function if no dementia is present, although they may recall things slower than usual. Crystallized intelligence increases. Menopause (40-50) and andropause (50-90) cause changes as well. Skin tends to exhibit dryness, wrinkling, and loss of thickness; this is accelerated with sun exposure.
Oral medications will have a slower onset of action due to decrease in gut motility. Since most meds in the elderly are for chronic conditions, this negates the problem. It can be an issue with pain meds. Muscle mass changes affect drug therapy by reducing the volume of distribution of water-soluble (hydrophilic) drugs. Lipophilic medications, though, have a larger volume of distribution due to increased fat. Less activity of the P-glycoprotein efflux transporter decreases drug transport out of the brain, increasing drug concentrations in the brain. Malnutrition leads to hypoalbuminemia, which leads to decreased protein binding, and an increased amount of free drug (this happens with phenytoin and warfarin).
Phase I reactions (oxidation, reduction, demethylation, hydroxylation) are decreased in the elderly. Phase II reactions do not change in the elderly. There is a gradual loss of renal function in the elderly.
Some side effects are particularly problematic in the elderly due to altered pharmacokinetics. Anticholinergic effects of antihistamines, tricylics, and antipsychotics are enhanced. Orthostatic hypotension seen with antihypertensives and tricyclics is more prevalent. Delirium from anticholinergics, analgesics (meperidine), and benzodiazepines is increased. The GI adverse effects of any drug are increased.
Elderly people also have decreased functional reserve capacity. This means they don’t realize when things are wrong such as dehydration. It also means it takes longer for problems to correct themselves. Also, many patients have multiple disease states, which makes it hard to assess the cause of a certain problem. Many symptoms also tend to get blamed on general aging.

Front 3

3. Recognize drug-related problems associated with overuse, inappropriate prescribing, underuse and medication adherence in the elderly.

Back 3

The major risk factors for drug problems are that elderly patients are on so many medications and have multiple disease states. Overuse is common, which is administration of more medications than clinically indicated.
Underuse of medications is also common in conditions such as iron for anemia, cholesterol-lowering drugs, oral hypoglycemics for diabetes, bronchodilators for COPD, pain medications, potassium supplements, and stool softeners.
Reasons for non-compliance include complex drug regimens, intentional non-adherence, and dementia and cognitive impairment.

Front 4

4. Apply basic principles of pharmacotherapy for commonly used medications to the geriatric patient.

Back 4

Anticholinergic agents can cause delirium and confusion in the elderly patient. Multiple drugs on the same regimen with only a small amount of anticholinergic effect can add up to cause confusion (Anticholinergic load). Constipation is another significant problem.
Antipsychotics (especially older ones) are associated with anticholinergic side effects. They can increase mortality due to stroke and QT prolongation. Newer antipsychotics are preferred.
Anxiolytics and hypnotics pose problems. Long-acting benzodiazepines should be avoided because the drug half-lives are further extended in the elderly. Zolpidem and zaleplon are preferred for short-term treatment of insomnia. Lorazepam and oxazepam are preferred for anxiety unless buspirone can be used.
Antidepressants – tricyclics should be avoided due to anticholinergic, antihistamine, and antidopaminergic effects (nortriptyline and desipramine are most suitable if needed). SSRIs have fewer side effects but you must watch for drug-drug interactions (sertraline, citalopram, escitalopram are preferred).
Anagesics – Start with Tylenol. NSAIDs post a greater risk for GI bleeding in the elderly. COX-2 may reduce this risk short term. Both can cause renal impairment. Meperidine and propoxyphene use should be avoided in the elderly due to active metabolites that lead to toxicity.
Anti-epileptic drugs tend to cause confusion and have altered PK’s in the elderly. Levetiracetam has the fewest adverse effects and drug-drug interactions.
Digoxin doses must be adjusted in the elderly. It major toxicity is anorexia and weight loss.
Warfarin has increased sensitivity and a high risk for adverse drug interactions in the elderly.
Antihypertensives lead to an increased risk of orthostatic hypotension and falls. Alpha-blockers should not be used first line (when used, titrate up).
First generation sulfonylureas tend to accumulate and cause risk for prolonged hypoglycemia in the elderly. Glipizide is preferred of glyburide. Metformin is useful unless the patient has reduced kidney function or CHF.

Front 5

What are the common chronic conditions that limit activity of the elderly?

Back 5

1. arthritis
2. hypertension
3. heart disease
4. hearing impairment
5. cataracts
6. diabetes

Front 6

What happens to absorption in the elderly?

Back 6

Oral meds have a slower onset of action due to decrease in gut motility. Since most medications in the elderly are used for chronic conditions, this negates the problem. This is an issue in pain meds.

Front 7

What happens to distribution in the elderly?

Back 7

1. reduced volume of distribution for water soluble drugs
2. larger volume of distribution for fat soluble drugs
3. less activity of P-glycoprotein decreases drug transport out of the brain, greater concentration of drug in brain
4. malnutrition leads to hypoalbuminemia, protein bound drugs will show an increase amount of free drug

Front 8

What types of side effects are particularly problematic in the elderly?

Back 8

1. Anticholinergic
2. Orthostatic hypotension
3. Delirium
4. GI side effects

Front 9

What are the 3 most important questions to ask about the appropriateness of a medication prescribed for an elderly patient?

Back 9

1. Is there an indication for the medication?
2. Is the medication effective for the condition?
3. Is the dosage correct?