Adverse Drug Reactions

Question 1

On Target ADRs Examples

Answer 1

Sedation with anxiolytics
Bleeding with anticoagulants
Hypoglycaemia coma from insulin
Opioids respiratory depression
Cough from ACE inhibitors
Warfarin excessive bleeding

Question 2

What is an on target adverse drug reaction?

Answer 2

ADR effect related to pharmacological mechanism.
Predictable and well understood.
Managed by dose reduction.
Usually reversible, but not always easily e.g. opioid analgesic dependance.

Question 3

What is an off target drug adverse drug reaction?

Answer 3

Unrelated to primary mechanism of action of drug.
Usually unpredictable, uncommon, dose reduction does not always prevent.
Can be predictable, severe and immunological in nature (see examples)

Question 4

Off target drug ADRs examples

Answer 4

Can be predictable paracetamol hepatotoxicity.
Often reactive metabolite of parent drug initiates.
Often immunological in nature, e.g. Penicillin induced anaphylaxis, bone marrow suppression. [Hypersensitivity reactions]
Often severe e.g. carcinogenesis, disordered foetal development

Question 5

COX2 Inhibitors and NSAIDs ADRs

Answer 5

On target ADR
Cause dose dependent myocardial infarction due to decrease in prostacyclin synthesis and increase in blood pressure