Pharmacogynetics and ADR's

Question 1

Define an adverse drug reaction

Answer 1

An adverse drug event occurs “while a person is taking a drug , but is not necessarily due to the drug”

Question 2

State and describe the two types of adverse drug reactions [ADR’s]/

Answer 2

Type A
Predictable
Dose related
Often an exaggeration of the therapeutic effects
E.g. a patient taking an antihypertensive drug may feel dizzy or light headed

Type B
Unpredictable
May not be dose related
Includes allergic reactions
E.g.- skin rashes, jaundice and anaemia

Adverse drug reactions are classified into six types (with mnemonics): dose-related (Augmented), non-dose-related (Bizarre), dose-related and time-related (Chronic), time-related (Delayed)

Question 3

Type B ADR is classified as a drug allergy. How does this happen in the body? and what are the reactions

Answer 3

Occur when the body forms antibodies to a particular drug
An allergic reaction occurs after second or subsequent exposure (may be delayed)

Reactions may be:
Anaphylactic
Tissue specific
Immune complex- mediated
Cell mediated

Question 4

Examples of drugs that may fall under type b

Answer 4

Penicillins, metronidazole, anticonvulsants, antibiotics, local anaesthetic creams

Question 5

Pharmacovigilance meaning

Answer 5

The science and activities relating to the detection, assessment, understanding and prevention of adverse effects or any other drug-related problem

Question 6

What is the NZ centre for adverse reactions monitoring

Answer 6

CARM - National monitoring centre for ADR’s.

Question 7

Risk factor for ADR’s

Answer 7

Age (elderly)
Gender- women
Concurrent disease
Genetics
History of past reactions
Pharmaceutics (chemical characteristics)
Route of administration
Dose duration and frequency

Question 8

pharmacokinetic interaction. Distribution

Drugs may compete for protein binding sites. Name an example

Answer 8

Warfarin is 99% protein bound and so only 1% is free to exert an effect. If a second drug displaces any of the Warfarin bound to protein the amount of free Warfarin is significantly increased

Question 9

Enzyme induction - When a drug is present in the body for prolonged periods the amount of metabolising enzyme can increase and thus speed up metabolism of that drug.
This can decrease the concentration of active drug meaning the patient may require an increase in drug dosage
E.g. Rifampicin, Morphine

Name examples of enzyme inducers

Answer 9

Other substances can act as enzyme inducers also E.g.- alcohol, tobacco smoke.

Question 10

If a drug or food inhibits a metabolising enzyme it is known as an

Answer 10

enzyme inhibitor.

Question 11

Substances that cause enzyme inhibition may lead to

Answer 11

the accumulation of drugs in the body leading to toxicity

Question 12

CYP3A4 metabolises up to __% of all CYP450 metabolised drugs

Answer 12

50%

Question 13

Excretion
Drugs may compete for the same transport system

name an example

Answer 13

Probenecid with IV penicillin- inhibits tubular secretion of the penicillin therefore prolonging its action

Question 14

Several drugs are known to interact with foods

Answer 14

Tetracycline and milk products
Warfarin and Vitamin K containing foods
Grapefruit Juice

Question 15

define Pharmacogenetics

Answer 15

The effect of genetics on drug action and elimination

Question 16

pharmacogenetics - Human populations can be divided into two groups extensive and poor metabolisers

name an example of pharmacogenetics

Answer 16

E.g 6-10% of the Caucasian population lack the enzyme to metabolise codeine (

Question 17

This drug only has an effect on tumours in people who’s tumours display a specific genetic defect

Answer 17

E.g Trastuzumab (Herceptin).

Question 18

Pharmacogenomics meaning

Answer 18

Area of study looking at individual variation in drug response due to genetic factors

Question 19

A patient had a cardiac arrest when he was inadvertently given an overdose of potassium supplement. This incident can be defined as a/an:

Answer 19

This is an example of an adverse drug event (ADE). ADE includes under- or over-medication resulting from errors in drug ordering, dispensing or administration.

Question 20

Tardive dyskinesia as a result of long-term neuroleptic use can by categorised as which type of adverse drug reaction?

Answer 20

Type C (Continuous) ADRs occur because of long-term drug use.

Question 21

There are more adverse drug reactions among:

Answer 21

ADRs among the elderly are more common because they are more likely to be taking multiple medications.

Question 22

Certain genetic factors predispose individuals to ADRs:

T/F

Answer 22

True - This has been known since the late 1950s; the move towards the era of pharmacogenetics will enable medication prescriptions to be tailored to individual genotypes.

Question 23

Drug allergy is a common adverse drug reaction:

T/F

Answer 23

F - It usually occurs in a small number of individuals taking the drug.

Question 24

Individuals with a history of atopic disease are more likely to experience adverse drug reactions: T/F

Answer 24

T - There is a positive association between atopic disease (e.g. asthma, hay fever and eczema) and allergic drug reactions.

Question 25

An adverse drug reaction (ADR) is defined as

Answer 25

noxious, unintended drug response

Question 26

An anaphylactic reaction to a small dose of penicillin can by categorised as which type of adverse drug reaction:

Answer 26

Type B

Question 27

The development of cervical cancer in female offspring of mothers who used to take diethylstilboestrol (DES) during pregnancy can by categorised as which type of adverse drug reactions:

Answer 27

Type D (Delayed) ADRs are characterised by the appearance of delayed effects.

Question 28

Break down the four types of ADR’s.

Answer 28

Characteristics of type A (Augmented) ADRs include:
i) predictability; ii) dose response relationship; iii) common occurrence; iv) high morbidity and low mortality.

    Characteristics of type B (Bizarre) ADRs include: i) unpredictability; ii) no dose response relationship; iii) uncommon occurrence; iv) high morbidity and high mortality.

     Type C (Continuous) ADRs occur because of long-term drug use.

    Type D (Delayed) ADRs are characterised by the appearance of delayed effects.

Question 29

The physician has written admission orders, and the nurse is transcribing them. The nurse is having difficulty transcribing one order because of the physician’s handwriting. Which of the following is the best action to take at this time? The nurse should:

Answer 29

do not transcribe a prescription as this is not within the RN’s scope of practice

Question 30

Many ADR’s are ____ related

Answer 30

Dose