Brainscape's Knowledge GenomeTM

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


See full index

Year 2: Pharmacology and Therapeutics > Adverse drug reactions > Flashcards

Adverse drug reactions Flashcards

1
Q

Define an adverse drug event

A

A preventable (medication errors) or unpredicted (ADR) medication event with harm to the patient.

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

What are the classifications of ADRs?

A

Onset
Severity
Type

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

What are the different categories of onset in ADRs?

A

Acute - within 1 hour. e.g anaphylaxis
Sub-acute - 1 to 24 hours
Latent > 2 days

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

What are the different categories of severity in ADRs?

A

Mild - requires no change in therapy
Moderate - requires change in therapy
Severe - disabling or life-threatening

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

Describe severe ADR?

A

Life threatening - results in death

Requires or prolongs hospitalisation
Requires intervention to prevent permanent injury

Severe ADR can causes:

  • Disability
  • Congenital anomalies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the different types of ADRs?

A 
Type:
A - Augmented pharmacological effect
B - Bizarre
C - Chronic
D - Delayed
E - End-of-treatment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe type A ADRs?

A
  • Extension of pharmacological effect = usually predictable and dose dependent
  • Responsible for at least 2/3s of ADRs

e.g e.g., atenolol and heart block, anticholinergics and dry mouth, NSAIDS and peptic ulcer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Give examples of a relationship of ADR and dose?

A

Type A reactions:

Paracetamol - sudden increase in ADR at specific dose.
Digoxin - linear increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe type B ADRs?

A
  • idiosyncratic or immunologic reactions
  • includes allergy and “pseudoallergy”
  • rare (even very rare) and unpredictable

e.g., chloramphenicol and aplastic anemia, ACE inhibitors and angioedema (pseudo-allergy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe type C ADRs?

A
  • associated with long-term use
  • involved dose accumulation

e.g., methotrexate and liver fibrosis - dependent on the total amount of methotreaxate given, antimalarials and ocular toxicity - the more you give the more damage

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

Describe type D ADRs?

A
  • delayed effects (sometimes dose independent)
  • carcinogenicity (e.g. immunosuppressants)
  • teratogenicity (e.g. thalidomide)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe type E ADRs?

A

Withdrawal reactions
- Opiates, benzodiazepines, corticosteroids (fits)

Rebound reactions
- Clonidine - if you miss a dose your hypertension could get even worse (slide 17), beta-blockers, corticosteroids

“Adaptive” reactions
- Neuroleptics (major tranquillisers) You get abnormal random movements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Classify the types of allergies and give examples.

A

Type I - immediate, anaphylactic (IgE)
e.g., anaphylaxis with penicillins

Type II - cytotoxic antibody (IgG, IgM)
e.g., methyldopa and hemolytic anemia

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

Give some examples of pseudoallergies?

A

Aspirin/NSAIDs – bronchospasm (induction into proinflammatory compounds - block the COX-1 enzyme, production of thromboxane and some anti-inflammatory prostaglandins is decreased)

ACE inhibitors – cough/angioedema (due to bradykinin not being broken down) Angioedema similar to anaphylaxis.

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

List the common causes of ADRs?

A 
Antibiotics
Antineoplastics* - Acting to prevent, inhibit or halt the development of a neoplasm (a tumor).
Anticoagulants
Cardiovascular drugs*
Hypoglycemics
Antihypertensives
NSAID/Analgesics*
CNS drugs*
  • account for 2/3s of fatal ADRs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the correlation between ADR and drug use?

A

The greater the number of medications taken the greater the frequency of ADR

17
Q

What are the two stages in ADR detection?

A

Subjective report
- patient complaint

Objective report:

  • direct observation of event
  • abnormal findings
    1) physical examination
    2) laboratory test
    3) diagnostic procedure

Rare events will probably not be detected before the drug is marketed.

18
Q

What is the Yellow Card Scheme?

A
  • introduced in 1964 after thalidomide.
  • run by the Medicines and Healthcare Products Regulatory Agency (MHRA)
  • entirely voluntary: can be used by doctors, dentists, nurses, coroners and pharmacists, and members of the public
  • includes blood products, vaccines, contrast media
  • for established drugs only report serious adverse reactions (fatal, life-threatening, needing hospital admission, disabling)
  • for “black triangle “ drugs (newly licensed, usually <2 years) report any suspected adverse reaction
19
Q

What are the different types of drug interactions?

A

Pharmacodynamic - related to the drug’s effects in the body. Receptor site occupancy

Pharmacokinetic - related to the body’s effects on the drug. Absorption, distribution, metabolism, elimination

Pharmaceutical - drugs interacting outside the body (mostly IV infusions 0 reactions inside transfusion bags)

20
Q

Describe pharmacodynamic drug interaction?

A

Examples of pharmacodynamic interactions can be additive, synergistic, or antagonistic effects from co-administration of two or more drugs

  • Synergistic actions of antibiotics
  • Overlapping toxicities - ethanol and benzodiazepines (CNS depressants)
  • Antagonistic effects - anticholinergic medications (amitriptyline and acetylcholinesterase inhibitors)
21
Q

What are the four different pharmacokinetic drug interactions?

A
  • Alteration in absorption
  • Protein binding effects
  • Changes in drug metabolism
  • Alteration in elimination
22
Q

Describe alterations in absorption

A

Chelation

  • Irreversible binding of drugs in the GI tract
  • Tetracyclines, quinolone antibiotics - ferrous sulfate (Fe2+), antacids (Al3+,Ca2+, Mg2+), dairy products (Ca2+)
  • The antibiotics and ferrous sulfate/antacids are not absorbed because they bind together.
23
Q

What are protein binding interactions?

A

Competition between drugs for protein or tissue binding sites:
- Increase in free (unbound) concentration may lead to enhanced pharmacological effect

PB interactions are not usually clinically significant
but a few are (mostly with warfarin - very protein pound. Displacing that is bad)

24
Q

Summarise drug metabolism and elimination

A

See slide 35

25
Q

What reactions are involved in phase I and II metabolism?

A

Phase I: molecule is structurally changed.

  • oxidation
  • reduction
  • hydrolysis

Phase II: Stick another molecule onto the drug

  • Glucuronidation
  • Sulphation
  • Acetylation
26
Q

Describe drug metabolism interactions?

A

Drug metabolism is inhibited or enhanced by coadministration of other drugs.

27
Q

Describe the CYP450 substrates?

A

Metabolism by a single isozyme (predominantly)

  • Few examples of clinically used drugs
  • Examples of drugs used primarily in research on drug interactions

Metabolism by multiple isozymes
- Most drugs metabolized by more than one isozyme
Imipramine: CYP2D6, CYP1A2, CYP3A4, CYP2C19
- If co-administered with CYP450 inhibitor, some isozymes may “pick up slack” for inhibited isozyme

28
Q

What can inhibit CYP450?

A
  • Cimetidine
  • Erythromycin and related antibiotics
  • Ketoconazole (anti-fungal)
  • Ciprofloxacin and related antibiotics
  • Ritonavir and other HIV drugs
  • Fluoxetine (SSRI antidepressant) and other SSRIs
  • Grapefruit juice

Inhibition is very rapid

29
Q

What can induce CYP450?

A

Antiepileptic drugs:

  • Rifampicin
  • Carbamazepine
  • (Phenobarbitone)
  • (Phenytoin)
  • St John’s wort (hypericin): Antidepressant

Induction takes hours/days

30
Q

Describe some drug elimination interactions?

A

Renal tubule:

GOOD: Probenecid and penicillin (prevented penicillin from being excreted keeps it around for longer)

BAD: Lithium and Thiazides (increases excretion sodium at the expense of lithium. We need lithium)

31
Q

What are some deliberate interactions?

A
  • levodopa + carbidopa
  • ACE inhibitors + thiazides
  • penicillins + gentamicin
  • salbutamol + ipratropium

Year 2: Pharmacology and Therapeutics (33 decks)

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