1 - Errors, Reactions, Special Populations

Question 1

What is a side effect?

Answer 1

A nearly unavoidable secondary drug effect produced at therapeutic doses

Question 2

What is the technical definition of toxicity?

Answer 2

A detrimental physiologic effect caused by a supratherapeutic drug dose

However, usually used to refer to any severe ADR, even if the dose that caused it was therapeutic

Severe neutropenia from chemo can be considered toxicity, even though it’s produced because the drug dose is therapeutic

Question 3

What percent of adverse drug reactions are true allergies?

Answer 3

10%

Question 4

The intensity of an allergic reaction is determined primarily by:

Answer 4

the degree of sensitization of the immune system

NOT the size of the dose

Question 5

Most serious allergic reactions are caused by one drug family:

Answer 5

the penicillins

Question 6

What is an idiosyncratic effect?

Answer 6

an uncommon drug response resulting from a genetic predisposition

Question 7

Give an example of an idiosyncratic effect

Answer 7

When patients with G6PD take sulfonmamides or aspiring they develop hemolysis

Question 8

What does iatrogenic mean?

Answer 8

Caused by medical care or treatment or drugs

Question 9

What percentage of medication errors occur when patients undergo a transition in care?

Answer 9

60%! This is why med recs are so essential

Question 10

How effect is BCMR?

Answer 10

Reduces error by 85%

Question 11

What are the top four pathologic conditions that profoundly effect drug response?

Answer 11

1. Kidney Disease
2. Liver Disease
3. Acid-Base Imbalance
4. Altered Electrolyte Status

Question 12

Kidney disease reduces ______

Liver disease reduces ______

Answer 12

excretion

metabolism

Question 13

It actually is not very common for electrolytes to alter the effectiveness of a drug. What is a notable exception?

Answer 13

Digoxin

In the presence of hypokalemia, it is very likely to induce dysrhythmias

Question 14

What is the difference between pharmacodynamic tolerance and metabolic tolerance?

Answer 14

Pharmaco: result of chronic receptor occupation, resulting in an increased MEC

Metabolic: tolerance that results from accelerated drug metabolism. Some drugs (like barbiturates) induce the synthesis of hepatic drug-metabolizing enzymes, so the more drug you take, the more metabolizing enzymes the body makes. Interestingly, does not effect the MEC. Only the duration.

Question 15

What is tachyphylaxis?

Answer 15

reduction in drug responsiveness due to repeated dosing over a short period in time

(constant nitroglycerin - like a patch - results in a loss of cofactor. intermittent dosing, on the other hand, allows cofactor to build back up between doses and prevents tachyphylaxis)

(Also, pitocin for labor)

Question 16

Enteric coatings, sustained release, and chewable tablets are examples of formulations that alter:

Answer 16

bioavailability

Question 17

Bioavailability differences occur primarily with _____ preparations, not ______

Answer 17

oral

IV

Question 18

For a drug that is absorbed in the intestines, how would you expect diarrhea to effect bioavailability?

Constipation?

Answer 18

Decrease, due to less time in the intestines

Increase, due to excessive time in the intestines

Question 19

What’s the difference between genetics and genomics?

Answer 19

• Genetics*: how genetic traits are passed from one generation to another
• Genomics*: study of the genome and how genes interact with each other and the environment

Question 20

What is pharmacogenomics?

Answer 20

The study of how genes affect a person’s response to drugs

Question 21

What is a biomarker?

Answer 21

A measurable substance that indicates the existence of a genetic variation

Question 22

Genetic variations usually alter drug response by altering:

Answer 22

metabolism

Question 23

What is a possible explanation for increased efficacy of beta blockers in caucasions?

Answer 23

European ancestry has higher incidents of variants in genes that code for B1 ADRs that make them hyper-sensitive to beta blockers

Question 24

How does pregnancy influence GFR?

Answer 24

By the third trimester, it’s doubled

results in accelerated clearance

Question 25

If a patient with seizures becomes pregnant, will their drug dose need to be changed?

Answer 25

If it’s phenytoin, carbamazepine, or valproic acid, it will

The hepatic clearance of these three drugs is increased during pregnancy

Question 26

Why is heparin avoided during pregnancy?

Answer 26

It causes osteoporosis and can cause compression fractures of the spine

Question 27

What percent of congenital anomalies are genetic?

Answer 27

25%

Question 28

If you don’t want a medication to be passed through breastmilk, when is the ideal time to take a dose?

Answer 28

Immediately after breastfeeding

Question 29

How long does it take for gastric acidity to reach normal levels in infants?

Answer 29

two years!

Question 30

How are IM injections absorbed in the neonate?

in the infant?

Answer 30

very slow and erratic

More rapid even than in adults

Question 31

How is transdermal absorption altered in infancy?

Answer 31

much more rapid and complete in infants than in older children and adults

Question 32

Is protein binding increased or decreased in infants?

Answer 32

Decreased.

Low albumin, and endogenous compounds (fatty acids, bilirubin) are competing with drugs for binding sites

Question 33

If you gave a protein bound drug to an adult and an infant, who would have the higher free levels?

Answer 33

The infant, which will intensify the effect

Question 34

When does protein-binding capacity reach adult values?

Answer 34

10-12 months

Question 35

At what age are adult levels of renal function acheived?

Answer 35

1 year

Question 36

Do children (>1 year) metabolize drugs faster or slower?

Answer 36

Faster

Question 37

How is absorption altered in geriatric patients?

Answer 37

The percentage of an oral dose that is absorbed does NOT change with age

The rate at which that does is absorbed DOES slow down

(d/t delayed gastric emptying and reduced splanchnic blood flow)

Question 38

What are the four major factors that alter drug distribution in older adults?

Answer 38

1. Increased percentage of body fat (forms a lipid-soluble storage depot, which reduces plasma levels and reduces response)
2. Decline in lean body mass and total body water (water soluble drugs are distributed very little, leading to very high serum values and more intense effects)
3. Reduced concentration of albumin (causes free levels of drugs to rise)

Question 39

How is drug metabolism impacted in geriatric patients?

Answer 39

hepatic drug metabolism tends to decline

d/t reduced hepatic blood flow, reduced liver mass, decreased activity of some hepatic enzymes

Question 40

What is the most important cause of the high prevalence of adverse drug reactions in the geriatric population?

Answer 40

drug accumulation secondary to reduced renal excretion

Question 41

What is the proper lab test to determine renal function in older adults?

Why?

Answer 41

creatinine clearance, NOT serum creatinine

In older patients, their serum creatinine will be low simply because they have less muscle mass. As such, creatinine serum levels may be normal even though the kidneys are functioning very poorly

Question 42

Are beta blockers more or less effective in geriatric patients?

Why?

Answer 42

Less, even when present in the same concentration

May be due to a reduction in the number of beta receptors and/or a reduction in the affinity of the remaining beta receptors for the blocking agents

Question 43

ADRs are ______ more common in older adults

Answer 43

7x

Question 44

Which is a more common reason for hospital admissions due to nonadherence: underdosing or overdosing?

Answer 44

90% of the time its under dosing, leading to a therapeutic failure