Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology and Therapeutics > 21. Adverse drug reactions > Flashcards

21. Adverse drug reactions Flashcards

1
Q

What percentage of adverse drug reactions are preventable?

A

30-60%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How are ARDs classified (3 ways)?

A
  • Onset
  • Severity
  • Type
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How is the onset of ARDs categorised?

A
  • Acute: within 1 hour
  • Sub-acute: 1-24 hours
  • Latent: >2 days
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How is the severity of ARDs categorised?

A
  • Mild: no change in therapy required
  • Moderate: change in therapy required, maybe additional treatment, possible hospitalisation
  • Severe: disabling, life-threatening, causes damage to foetus, requires intervention to prevent permanent injury
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How is the type of ARDs categorised?

A
  • Type A - augmented pharmacological effect (majority)
  • Type B - bizzare
  • Type C - chronic
  • Type D - delayed
  • Type E - end-of-treatment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Outline type A reactions

A
  • Augmented pharmacological effect of known drug
  • Usually predictable and often dose dependent
  • Responsible for 2/3 of ADRs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How dose the toxicity of paracetamol and digoxin increase with dose?

A
  • Paracetamol slowly increases toxicity through the therapeutic affect, then sharply increases just after
  • Digoxin increases more than initial paracetamol rise, but is consistent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Outline type B reactions

A
  • More dramatic
  • Idiosyncratic (particular to given individuals) or immunologic reactions
  • Include allergy and pseudo-allergy
  • Very rare and unpredictable
  • e.g. ACEi and angioedema (pseudo-allergy)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Outline type C reactions

A
  • Associated with long-term use of drugs
  • Involve dose accumulation
  • e.g. methotrexate (chemotherapy/immunosuppressant) and liver fibrosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Outline type D reactions

A

• Delayed effects (sometimes dose dependent, but not strongly linked)
• e.g. carcinogenicity (immunosuppressants)
• e.g. teratogenicity (thalidomide)
•

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Outline type E reactions

A
  • Withdrawal reactions - opiates, benzodiazepines, corticosteroids
  • Rebound reactions - clonidine, beta-blockers, corticosteroids
  • Adaptive reactions - neuroleptics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the rebound reaction of clonidine withdrawal

A
  • Used to be used as an anti-hypertensive
  • Alpha-2 agonist - reduced release of NA - drop in BP
  • If you miss 1 or 2 doses, substantial rise in BP
  • Long-term use of clonidine causes long-term suppression of NA production
  • Leads to compensatory up-regulation in adrenergic receptors on post-synaptic neurone
  • NA has more receptors to act one when inhibition is removed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the 4 classifications for allergies and give an example for each?

A
  • Type I - immediate, anaphylactic (IgE) e.g. anaphylaxis with penicillin
  • Type II - cytotoxic antibody (IgG, IgM) e.g. methyldopa and hemolytic anaemia
  • Type III - serum sickness (IgG, IgM): antigen-antibody complex e.g. procainamide-induced lupus
  • Type IV - delayed hypersensitivity (T cell) e.g. contact dermatitis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Are pseudoallergies related to the immune system?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why are aspirin/NSAIDs associated with bronchospasm?

A

Pseudoallergy
• Inhibition of COX
• Reduction of prostanoid synthesis (bronchodilators)
• Body makes more leukotrienes instead (pro-inflammatory and bronchoconstrictors)
• Pharmacological reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the signs and symptoms of angioedema similar to?

A

Anaphylaxis, but much less severe

17
Q

What are the most common causes of ADRs?

A
  • Antineoplastic drugs (as they are given to so many people)
  • Cardiovascular drugs
  • NSAID/analgesics
  • CNS drugs

(also antibiotics, anticoagulants, antihypertensives)

18
Q

How do we detects ARDs (problem with disease or drugs)?

A
  • Subjective report - patient complant
  • Objective report - direct observation
  • Sometimes need a larger number of events if e.g. 1/100 chance
19
Q

What is the yellow card scheme?

A
  • Public way of detecting adverse reactions (introduced in 1964 after thalidomide)
  • No system of checking safety before then
  • Scheme is voluntary and can be used by doctors, coroners, pharmacists, members of the public etc.
  • Included blood products, vaccines, contrast media
  • Only report serious ADRs for established drugs
  • Black triangle drugs (newly licensed <2 years) - report any suspected adverse reaction
20
Q

What are the 3 varieties of drug interactions?

A
  • Pharmacodynamic - related to drug’s effects in the body
  • Pharmacokinetic - related to body’s effect on the drug (e.g. metabolism)
  • Pharmaceutical interactions - drugs interacting outside the body (mostly IV infusions)
21
Q

Describe the 3 types of pharmacodynamic drug interactions

A
  • Additive - 2 drugs producing an effect of the sum of the drugs - overlapping toxicities e.g. ethanol + benzodiazepines
  • Synergistic actions of antibiotics - 2 drugs potentiate each others actions for a greater effect than expected
  • Antagonistic effects e.g. anticholinergic medications (amitriptyline and acetylcholinesterase inhibitors)
22
Q

What are the 3 types of pharmacokinetic drug interactions?

A
  • Alterations in absorption (chelation)
  • Protein binding interactions
  • Drug metabolism and elimination
23
Q

What does alterations of absorption (chelation) involve in ‘pharmacokinetic interactions’?

A
  • Irreversible binding of drugs in the GIT
  • Tetracyclines and quinolone antibiotics can be involved
  • They form a stable chelate with mineral ions e.g. ferrous sulphate, dairy products and antacids
  • Therefore you don’t absorb the ion or antibiotic
24
Q

What do protein binding interactions (pharmacokinetic) involve?

A
  • Competition between drugs for protein or tissue binding sites
  • Increase in free (unbound) concentration - enhanced pharmacological effect
  • Most are not usually clinically significant, few are (mostly warfarin)
  • Warfarin is tightly bound to proteins - small displacement has drastic effects
25
Q

What’s the overall effect of phase I and II metabolism reactions on drugs?

A

More polar - easier to excrete by kidneys

26
Q

How can co-administration of drugs affect drug metabolism?

A

Drug metabolism interactions may be inhibited or enhanced by co-administration of other drugs

27
Q

Do most drugs undergo metabolism by a single or multiple isozymes (CYP450 substrates)?

A
  • Multiple isozymes

* If co-administered with CYP450 inhibitor, the other isozymes increase activity to compensate

28
Q

Over half of drug metabolism is done by which CYP450 isozymes?

A

CYP2D6 and CYP3A4

29
Q

Give examples of CYP450 inhibitors

A
  • Cimetidine (peptic ulcer treatment)
  • Erythromycin
  • Ketoconazole
  • Ritonavir
  • Fluoexetine (SSRI)
  • Grapefruit juice
30
Q

Give examples of CYP450 inducers

A
  • Rifampicin (antibiotic)
  • Carbamazepine
  • St John’s Wort (hypericin)
31
Q

How long does CYP450 inhibition and induction take?

A
  • Inhibition - rapid

* Induction - hours/days

32
Q

Where do drug elimination interactions almost always take place?

A

Renal tubule

e. g. probenecid reduced elimination of penicillin (good)
e. g. thiazides reduce clearance of lithium (toxic)

33
Q

Give examples of deliberate interactions that are commonly prescribed?

A
  • Levadopa and carbidopa
  • ACEi and thiazides
  • Penicillins and gentamicin
  • Salbutamol and ipratropium (beta-2 antagonist + anticholinergic) - in asthma to bronchodilate

Pharmacology and Therapeutics (33 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions