adverse drug reactions

Question 1

define adverse drug reactions ( ADR)

Answer 1

unwanted or harmful reactions following the administration of drugs or combination of drugs under normal conditions of use and is suspected to be related to the drug

Question 2

define side effects

Answer 2

an unintended effect of a drug related to its pharmacological properties and can include unexpected benefits of treatment

Question 3

describe what occurs depending on the severity of ADRs

Answer 3

1. Can be mild e.g. nausea, drowsiness, itching rash
   2.Can be severe e.g. respiratory depression, neutropenia, catastrophic haemorrhage, anaphylaxis

Question 4

name some examples of adverse drug reactions

Answer 4

-Beta blockers
-Bradycardia and heart block are primary adverse effects
-Bronchospasm is a secondary pharmacological adverse effect

Question 5

what is the wider impact of ADRs for patients

Answer 5

Reduced Quality of life
Poor compliance
Reduced confidence in clinicians and the healthcare system
Unnecessary investigations or treatments

Question 6

what is the wider impact of ADRs for the NHS

Answer 6

Increased hospital admissions
Longer hospital stays
GP appointments
Inefficient use of medication

Question 7

what is the Thompson classification of ADRs

Answer 7

A-ugmented
B-izarre
C-hronic/continuing
D-elayed
E-nd of use/withdrawal
F-ailure of treatment
G-enetic

Question 8

describe type A reactions

Answer 8

(augmented pharmacological) – predictable, dose dependent, common, not life threatening
e.g- AKI with ACE inhibitors
Bradycardia with betablockers
Hypoglycaemia with gliclazide, insulin
Respiratory depression with opiates
Bleeding with anticoagulants

Question 9

describe type B reactions

Answer 9

(bizarre or idiosyncratic) – not predictable and not dose dependent, can cause serious illness or mortality
e.g Anaphylaxis with penicillins
Tendon rupture with quinolone antibiotics
Steven Johnson Syndrome with IV vancomycin

Question 10

describe type C reactions

Answer 10

(chronic) – osteoporosis and steroids, continue after the drug has been stopped
e.g Osteonecrosis of the jaw with bisphosphonates
Heart failure with pioglitazone

Question 11

describe type D reactions

Answer 11

(delayed) – malignancies after immunosuppression, becomes apparent some time after stopping the drug
e.g Leucopenia with chemotherapy

Question 12

describe type E reactions

Answer 12

(end of treatment) – occur after abrupt drug withdrawal
e.g Insomnia after stopping benzodiazepine
Rebound tachycardia after stopping beta-blocker
Nasal congestion after stopping xylometolazine nasal spray

Question 13

describe type F reactions

Answer 13

(failure of therapy) – unexpected treatment failure, poor compliance with administration Instructions, failure of oral contraceptive pill in presence of enzyme inducer

e.g Failure of oral contraceptive pill due to St John’s Wort
Failure of DOAC due to enzyme inducer (eg carbamazepine)
Failure of bisphosphonate due to taking with food

Question 14

describe type G reactions

Answer 14

( GENETIC)
drug causes irreversible damage to genome
e.g Phocomelia in children of women taking thalidomide

Question 15

what is an alternative way to classify ADRs

Answer 15

DoTS
Dose-relatedness
Timing
Susceptibility

Question 16

Describe D in DoTS

Answer 16

Hypersusceptibility: ADRs at subtherapeutic doses (eg anaphylaxis with penicillins)

Collateral effects (side effects): ADRs at therapeutic doses (eg hypokalaemia with loop diuretic)

Toxic effects: ADRs at subpratherapeutic doses (eg liver damage with paracetamol

Question 17

describe T in DoTS

Answer 17

Time independent: ADRs which can develop during any time during treatment (often due to clinical changes in the patient)

Question 18

describe S in DoTS

Answer 18

Susceptibility - certain groups/ populations may be more likely to delevlop ADRs

Question 19

what groups are more likely in S in DoTS to develop reactions

Answer 19

Age (anticholinergics in elderly patients)
Gender (metoclopramide in females)
Disease states (eg diclofenac in CVD)
Physiological states (eg phenytoin in pregnancy)

Question 20

how are ADRs identified?

Answer 20

Pre-clinical testing (computer models, cells and toxicity testing in animals)

Clinical trial data (pre-marketing evaluation)

Post marketing surveillance

Pharmacovigilance

Question 21

causes for ADRs

Answer 21

Pharmaceutical variation
Receptor abnormality
Drug-drug interactions

Question 22

when would you suspect an ADR?

Answer 22

Symptoms soon after a new drug is started
Symptoms after a dosage increase
Symptoms disappear when the drug is stopped
Symptoms reappear when the drug is restarted

Question 23

name common ADRs

Answer 23

Confusion
Nausea
Balance problems
Diarrhoea
Constipation
Hypotension

Question 24

what is the yellow card scheme

Answer 24

-The first ADR reporting scheme
-Collects spontaneous reports
-Acts as an ‘early warning system’ for identification of previously unrecognised reactions
-Provides information, about factors which predispose patients ADRs
-Continual safety monitoring of a product throughout its life span as a therapeutic agent

Question 25

what are the 4 pieces of critical information to induce on a yellow card?

Answer 25

-Suspected drug
-Suspect reaction
-Patient details
-Reporter details