Adverse Drug Reactions

Question 1

Therapeutic Index

Answer 1

Some biological effects of drugs are desirable (therapeutic)

Other undesirable (adverse) with a differs in: severity, incidence, mechanism of action, times sequence

Question 2

Adverse drug reaction is …..

Answer 2

An adverse drug reaction (ADR) is an
unwanted or harmful reaction which occurs
after administration of a drug or drugs and is
suspected or known to be due to the drug(s)

Question 3

Difference between adverse event and adverse drug reaction

Answer 3

Adverse event: undesired patient outcome whilst patient taking the
medication. Not necessarily due to drug

Adverse drug reaction: undesired patient outcome related to the drug

Question 4

ARDS from drugs may be

Answer 4

Unwanted or unexpected drug effects
 The result of an error in prescribing or administration
 Described as ‘minor’
 Described as ‘side effects’
 Give rise to toxicity (direct action of drug often at a high dose)
 Due to a drug interaction or pre-existing medicinal condition

Question 5

Example - cough with ACE inhibitors

Answer 5

ACE Inhibitors work by decreasing the
action of angiotensin converting
enzyme
 ~10% incidence of dry, tickly,
bothersome cough
 Exact mechanism unknown, but
thought to be related to the role ACE
plays in the breakdown of bradykinin,
which sensitises airway sensory
nerves, leading to a cough

Question 6

Example - Nausea with opiates

Answer 6

Opiate receptors exist in the CTZ within the
brain
 The CTZ specifically exists outside the blood
brain barrier
 It is thought that stimulation of these opiate
receptors can cause emesis
 At high doses, opiates can actually cross
the blood brain barrier and inhibit emesis
 Additionally, opiate receptors exist in the GI
tract, stimulation of which can cause
constipation

Question 7

Allergic Reactions: Mild-Moderate vs Anaphylaxis

Answer 7

Mild-moderate will have slower onset and generally present with urticaria or angio-odema

Anaphylaxis will generally present with sudden onset and rapid progression, with A, B or C
problems (and can present with skin problems as well)

Question 8

ARDS: immune system response

Answer 8

Some ADRs occur due to
our body’s immune response
 After exposure to an
allergen, our body’s immune
response can trigger a
hypersensitivity reaction,
with symptoms ranging from
itchy skin rash (urticaria)
through to anaphylaxis

*see picture in powerpoint