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Flashcards in Adverse Drug Reactions Deck (26)
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1

Define Type A ADR.

Extension of pharmacological effect
This is usually predictable and dose-dependent
This is the most common type of ADR – 2/3
Example: atenolol can slow down heart rate but if you give too much you could cause heart block

2

Define Type B ADR.

‘Bizarre’ type of ADR
Idiosynchratic or immunologic reactions – includes allergy or pseudoallergy
This is very rare and unpredictable
Example: chloramphenicol and aplastic anaemia

3

Define Type C ADR.

Associated with long-term use
Involves drug accumulation
E.g. methotrexate and liver toxicity

4

Define Type D ADR.

Delayed effects – sometimes dose independent
E.g. carcinogenicity and teratogenicity

5

Define Type E ADR.

Withdrawal reactions
Rebound reactions
Adaptive reactions

6

What is the ABCDE classification of adverse drug reactions?

A – augmented pharmacological action
B – bizarre
C – chronic
D – delayed
E – end of treatment

7

Describe the classification of allergies.

Type 1 – immediate, anaphylaxis (IgE)
Type 2 – cytotoxic antibody (IgG + IgM) ]
Type 3 – serum sickness (IgG + IgM)
Type 4 – delayed hypersensitivity (T cell)

8

What are the most common causes of ADRs

Antineoplastics
Cardiovascular drugs
NSAIDs/analgesics
CNS drugs

9

Why is it difficult to determine the incidence of drug-drug interactions?

There is a lack of availability of comprehensive databases
Difficulty in assessing OTC and herbal drug therapy use
Difficulty in determining contribution of drug interaction in complicated patients

10

What are the three types of pharmacodynamic drug interaction?

Additive effects- have same effect on similar receptors
Synergistic effects- potentiates effects of another
Antagonistic effects- decreases effects of another

11

What are the different types of pharmacokinetic drug interaction?

Alteration in drug absorption
Protein binding effects
Changes in drug metabolism
Alteration in elimination

12

What is an example of alteration of absorption?

Chelation- irreversible binding of drugs in GI tract

13

Explain what is meant by protein binding effects.

Competition between drugs for protein or tissue binding sites
It can increase free unbound concentration of a drug thus leading to enhanced pharmacological effects (e.g. warfarin)

14

Which cytochrome P450 enzymes are responsible for over half ofdrug metabolism?

CYP2D6
CYP3A4

15

Give a few examples of CYP450 inhibitors.

Cimetidine
Erythromycin
Ketoconazole
Ciprofloxacin
Ritonavir
Fluoxetine
Grapefruit juice

16

Give a few examples of CYP450 inducers.

Rifampicin
Phenytoin
Carbamazepine
St. John’s Wort (hypericin)
Phenobarbitone

17

Describe the difference in the speed of inhibition and the speed of induction of CYP450 enzymes.

Inhibition is RAPID
Induction takes hours/days

18

Give an example of a deliberate drug interaction.

ACE inhibitors and thiazides

19

3 ways to classify ADRs

Onset
Severity
Type

20

Onset classification

Acute <1 hour
Sub-acute 1-24 hours
Latent> 2 days

21

Severity classification

Mild- no therapy needed
Moderate- requires change in therapy or further treatment
Severe- disabling

22

What can happen in severe ADR

Congenital abnormalities
Prolonged treatment
Life threatening

23

What are pseudoallergies

Reactions to drugs that have no immune involvement

24

Examples of pseudoallergies

ACE inhibitors- cough/ angioedema
Aspirin- bronchospasm

25

What is the yellow card scheme

Came post thalidomide scandal
For drugs that are established you have to only report a serious ADR but for drugs that are "black triangle" which have only been on the market for less than 2 years you have to report any suspected ADR

26

3 types of drug interactions

Pharmacodynamic- drugs effect in body
Pharmacokinetic- bodys effects in body
Pharmaceutical- drug interaction outside body in IV infusions