Exam 1 - Pharmacology in Special Populations

Older adults make up a good percentage and contribute to most medication use compared to other populations

Geriatric patients are more likely to be taking multiple medications at once

What is the age group that, as a PA, you will most likely prescribe for?

Adult

Pregnant

Adolescent

Geriatric

Geriatric

Why is the geriatric population the population you need to be very careful with your medical decisions in procedures and prescribing?

Multiple drugs are taken at once resulting in high risk decision making

As a PA, working with the geriatric population, you should avoid reflex prescribing, what does this mean?

For any minor inconvenience or complaints, we should avoid prescribing medication if we can alleviate their symptoms through other means

As a PA, working with the geriatric population, why should you double check the medication list?

To eliminate any unnecessary drugs present

As a geriatric patient, would you expect:

GI absorption: higher or lower

Blood flow: increased or decreased

Acidity: increased or decreased

All of which affect which part of the ADME?

GI: lower

Blood flow: decreased

Acidity: decreased

Absorption

Which of the following would be a result of aging?

Total body water

Body fat

Plasma protein

All of which affect which part of the ADME?

TBW: decreases

Body fat: decreases

Albumin: decreases

Distribution

T or F. Cathartics increase rate of GI motility therefore decreasing the rate at which another drug passes through the GI tract

F - Cathartics accelerate defecation - IF cathartics is prescribed, this increases the rate of drug passage through the GI

T or F. Unadjusted dosing may cause increased serum drug concentration resulting in unwanted enhanced effected

In other words, if you do not adjust the drug dose, this results in __

T - Toxicity

T or F. Aging affects hepatic metabolism

T

T or F. There is a reliable method to estimate hepatic drug clearance similar to renal clearance

F - Liver clearance: refer to LFTs - Renal clearance: calculation

What phase of metabolism is affected by age? Phase I or Phase II

Phase 1: decreases with age

Phase 2: no changes in clearance

What phase (I or II) drugs that use CYP450 should be used cautiously in elderly patients?

Phase I - lower dose than average should be used

T or F. Age related changes in renal function are the most important physiologic factor that contribute to the development of ADRs

T

Which of the following are changes to renal function associated with age:

Increased number of nephrons

Decreased renal blood flow

Decreased GFR

Decreased tubular secretion

Decreased number of sclerosed glomeruli

Increased creatinine clearance

Decreased nephrons

Increased number of sclerosed glomeruli

Decreased C-Cl

Creatinine clearance decreases by __% every decade (10 years) after __

10% - 40 yo

If you suspect or observed renal impairment in geriatric patients, what should be done regarding:

Drug dosing vs. Intervals

Decrease drug dose

Increase intervals between dosing

__ is a muscle byproduct that is removed or eliminated by the kidney; used to measure renal clearance

Creatinine

T or F. Because elderly patients has low muscle mass, the level of creatinine is expected to be low

T

The amount of blood in which the drug is cleared per unit of time is estimated by assessing __

Blood draw creatinine levels

What is the gold standard in measuring creatinine levels in a patient?

24-hour urine collection; unlikely

T or F. Transdermal permeability or absorption is enhanced in premature infants and newborns

T - Skin is much thinner

T or F. Drug volumes of distribution varies as the body changes through growth and development

T

Which age group (neonates/infants, adults, geriatrics) have a higher total body weight consisting of more water than fat

Neonates - Infants

Would plasma proteins be lower or higher in infants or children?

Low

Why are drugs more readily available to the brain in premature infants?

Incomplete glial cell development

Is drug metabolism slower or faster in kids?

Is renal clearance higher or lower in kids?

Would this affect half-life of the drug in children?

Slower - Lower - Prolonged half-life; unable to metabolize and clear

At what point in an infant's life is the GFR 50% of an adult?

3rd week

At what point in an infant's life is the GFR equal to an adult?

6 months

What are 3 drugs you should avoid giving to children?

Aspirin

Tetracycline

Valproic acid

What are the 3 major ways a child is exposed to drugs which is likely to produce ADRs?

Transplacentally

Direct administration of drug to child

Breastfeeding

What is the best source for pediatric dose of a medication?

Package insert provided by the manufacturer

Which of the following (Young's, Fried's, Clark's rule) is the most accurate method to determine the pediatric dosing?

Clarks: weight based

For pediatric patients, __ matters the most as they determine whether or not the patient will be compliant

Taste: consider what's tolerable

90% of pregnant women are known to take more than 1 drug during their pregnancy: prescribed vs. self-admin

This might be a problem as medications are used to treat symptoms of pregnancy but can also pose harm to the unborn infant

Pharmacokinetics (Pregnancy)

1. Drug admin

2. vomiting/ low gastric emptying

3. Decreased absorption

4. Increased metabolism (increased activity of CYP450)

5. Increased renal flow (increased elimination)

Net: decreased plasma drug concentration

Pregnant women

Decreased absorption

Decreased distribution

Increased metabolism

Increased elimination

Why does most data regarding teratology and drugs come from experience instead of scientific research?

Pregnant women do not want to expose themselves or their babies to medications they do not the effects of

T or F. Any recommendation to interrupt breastfeeding carries the risk of premature weaning with risk of long term artificial feeding

T - If you can avoid prescribing medication that will be safe for the mother and infant, do so - If not, it can cause long term effects and loss of benefits from breastfeeding