Module 10

Question 1

Unintended and undesired responses from drugs

Answer 1

Adverse drug reactions - ADRs

Question 2

Canadian research suggests that ___% of hospital admissions in Canada are attributed to ADRs

Answer 2

7.5%

Question 3

ADRs include these 7 types.

Answer 3

Side effects
Drug toxicity
Allergic reactions
Idiosyncratic reactions
Carcinogenic effects
Mutagenic effects
Teratogenic effects

Question 4

Secondary to the main therapeutic effect of the drug, and are expected.

Answer 4

Side effects

Question 5

Side effects of a drug are often due to this.

Answer 5

Poor specificity or selectivity of a drug

Question 6

What are side effects of antihistamines? How do they come about?

Answer 6

Sides include drowsiness, dry mouth and urinary retention - sides occur when histamines bind to receptors in the brain

Question 7

Considered any severe adverse drug event

Answer 7

Drug toxicity

Question 8

Drug toxicity is often mediated by this.

Answer 8

Overdose

Question 9

Drug toxicity reactions are often extensions of the _________ effect.

Answer 9

therapeutic

Question 10

Allergy requires prior ___________.

Answer 10

Sensitization - patient exposed to the allergen

Question 11

What cells release histamine in allergies?

Answer 11

Mast cells

Question 12

Allergic reactions can vary from ______ and ______, to life threatening ________.

Answer 12

itching, rash

anaphylaxis

Question 13

What are the symptoms of anaphylaxis?

Answer 13

hypotension, bronchospasm, edema

Question 14

the intensity of allergic reactions are __________ of dosage size.

Answer 14

independent - therefore small doses can produce severe allergy

Question 15

What percentage of ADRs are due to allergy?

Answer 15

10%

Question 16

What is the most common drug class to cause drug allergy?
What are some others?

Answer 16

Penicillins

Sulfonamides and NSAIDs also cause allergy

Question 17

Reactions that occur rarely and unpredictably in the population

Answer 17

idiosyncratic reactions

Question 18

What accounts for the majority of idiosyncratic reactions?

Answer 18

Genetic polymorphisms

Question 19

Warfarin is metabolized by what enzyme?

Answer 19

CYP2C9

Question 20

6-mercaptopurine is metabolized by what enzyme?

Answer 20

TMPT - thiopurine methyltransferase

Question 21

Describe the CYP2C9 genetic polymorphism

Answer 21

Approx 15% of caucasians have a polymorphism that decreases metabolism (of warfarin).

Question 22

Describe the CYP2D6 genetic polymorphism.

Answer 22

10% of Caucasians and African Americans are poor metabolizers - these patients do not experience pain relief when they take codeine (converted to morphine)

Question 23

Describe the genetic polymorphism of thiourine methyltransferase.

Answer 23

Approximately 10% of patients have decreased activity, and 0.3% have none. - treatment with thiopurine drugs in these patients may result in life threatening bone marrow suppression

Question 24

Describe the genetic polymorphism in OATP1B1.

Answer 24

OATP1B1 is an uptrake transporter in the liver
15% of Caucasian and Asian patients have a polymorphism decreasing function
has been implicated in myopathy in patients taking statin drugs

Question 25

Describe the effect of G6PDH deficiency.

Answer 25

Important in RBC metabolism - may have RBChemolysis following analgesic or anti-malarial treatment in certain people of African or Middle-Eastern descent

Question 26

Why is it difficult to determine whether a drug is carcinogenic or not?

Answer 26

Takes years after the initial dose to appear

Question 27

Describe a drug that was pulled of the shelves for being carcinogenic.

Answer 27

Diethylstibestrol (DES) - used to be prescribed to prevent spontaneous abortions in high-risk pregnancies - female offspring often developed vaginal or uterine cancer

Question 28

Often drugs that are mutagenic are also carcinogenic or teratogenic. When would they be approved?

Answer 28

If there is sufficient evidence of safety from preclinical studies

Question 29

How are drugs tested for mutagenic potential?

Answer 29

Through the Ames test (ability of compound to induce mutations in bacteria)

Question 30

Drugs causing birth defects or impair fertility

Answer 30

Teratogens

Question 31

When do gross malformations occur when exposed to teratogens? When is function disrupted primarily?

Answer 31

1st trimester - gross malformations | 2nd and third trimester - affect function more than gross anatomy

Question 32

Transfer of drugs across the placenta is greatest in the ______ trimester. Why?

Answer 32

third b/c as the placenta develops, the surface area for transfer between maternal and fetal circulation increases and the barrier becomes thinner

Question 33

Describe how the pregnancy category of a drug works.

Answer 33

A - no evidence B - issues in animal studies; none in women C - benefits outweight harm - harm in animals studies but no well controlled studies for preggo women D - Clear evidence of risk to fetus but benefits outweight possible risks X - clear risk, should never be used in pregnant women - risks outweigh benefits

Question 34

The most common and important organ specific toxicity is observed in the ____ and the _____.

Answer 34

liver, heart

Question 35

Most common reason for an approved drug to be removed from the market.

Answer 35

Hepatotoxicity

Question 36

What are signs of hepatotoxicity?

Answer 36

jaundice, dark urine, light-coloured stool, nausea and vomitting

Question 37

Describe a blood test that can determine if liver function is impaired.

Answer 37

Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are liver enzymes that are usually low in the blood, unless the liver is damaged. In that case, they are higher

Question 38

Hepatotoxic drugs are often contraindicated for these patients.

Answer 38

Alcoholics Pts with liver disease Patients already taking hepatotoxic drugs

Question 39

Name each of the following ECG waves. Normal atrial depolarization rapid depolarization of the left and right ventricles Repolarization of the ventricles Wave that is not always seen Time required for the ventricles to repolarize

Answer 39

``` P-wave QRS complex T-wave U-wave QT interval ```

Question 40

A prolongation of the QT interval is a major risk factor for the development of this.

Answer 40

Torsades de pointes

Question 41

Life-threatening form of ventricular arythmia

Answer 41

Torsades de pointes

Question 42

Which gender is at higher risk for torsades de pointes?

Answer 42

Females since their QT interval is longer

Question 43

Drugs that prolong the QT interval should be used with caution in these patients.

Answer 43

Elderly | pts with bradychardia, heart failure, low potassium or congenital QT prolongation

Question 44

Most common cause of ADRs.

Answer 44

medication errors

Question 45

Medication error caused by a HCP.

Answer 45

iatrogenic error

Question 46

What are the 5 main types of medication errors.

Answer 46

``` Prescribing Dispensing Administration Patient education Patient ```

Question 47

HCP prescribes the wrong drug, wrong dose or wrong route

Answer 47

Prescribing medication error

Question 48

The prescription is correct but the pharmacist dispenses the wrong drug.

Answer 48

Dispensing medication error

Question 49

The HCP administers the incorrect dose and/or drug.

Answer 49

administration medication error (can also be made by a patient)

Question 50

Illiteracy or language barriers may cuase the patient to not comprehend the instruction and have a medication error.

Answer 50

Patient education medication error

Question 51

The patient understands the instructions but doesn't follow them

Answer 51

Patient medication error

Question 52

Confusion over drug names represents __ of all medication errors. What types of factors can increase drug naming errors?

Answer 52

15% | poor handwriting, illiteracy, strong accents

Question 53

``` Name what each of the following may be mistaken as. Plendil Nicoderm Flomax Dioval ```

Answer 53

Pletal Nitroderm Volmax Diovan

Question 54

The institute for Safe Medication Practices has put together a list of error prone abbreviations. Describe how each of the following may be mistaken and what the preferred way to write it is. ``` IU q.d. q.o.d. 1.0mg .5mg MgSO4 MS, MSO4 ```

Answer 54

IU - misread as IV or 10 - write units q.d. - misread as qid - write every day q.o.d. - misread as q.d. or q.i.d. - write every other day 1.0mg - misread as 10mg - do not use trailing zeros .5mg - misread as 5mg - use a leading zero MgSO4 - misread as morphine sulfate - write magnesium sulfate MS, MS04 - misread as magnesium sulfate - write morphine sulfate