Adverse Drug Reactions

Question 1

Define: adverse drug reaction

Answer 1

An ADR is an unwanted or harmful reaction experienced following the administration of a drug or a combination of drugs, and is suspected to be related to the drug

Question 2

Define: side effect

Answer 2

A side effect is a result of drug or other therapy in addition to or in extension of the desired therapeutic effect; usually but not necessarily, connoting an undesirable effect.

Question 3

What are the the two types of ADRs?

Answer 3

Type A and type B

Question 4

Outline the characteristics of type A Adverse drug reactions. (6)

Answer 4

1) pharmacology: augmented
2) predictable: yes
3) dose-dependent : yes
4) morbidity : high
5) mortality : low
6) management : dose reduction
- 80-90% of adverse drug reactions

Question 5

Outline the characteristics of type B adverse drug reactions (5)

Answer 5

1) pharmacology: idiosyncratic or allergic
2) predictable: no
3) dose-dependent: no
4) morbidity: high
5) management: stop drug

Question 6

Outline the importance of ADRs (3)

Answer 6

ADRs are common:

• 6.5% of hospital admissions were related to ADRs
• projected annual cost to the NHS of £466m
• over 2% patients admitted with an ADR died, suggesting an overall fatality rate from ADRs within the population of 0.15%

Question 7

Are ADRs avoidable? (4)

Answer 7

• 72% hospital admissions due to ADRs were definitely or possibly avoidable
• obvious interactions
• use of contra-indicated drugs
• drugs use in an inappropriate clinical indication or medically unnecessary

Question 8

Describe the pharmacists role in managing ADRs (6)

Answer 8

1) identify patients at risk of ADRs
2) identify drugs known to produce ADR and monitor patient appropriately
3) avoid use of drugs causing ADR where an equally effective and safer alternative exists
4) review patients medicines: stop unnecessary medicines, check for interactions and contraindications
5) ensure patient are counselled on the correct use of their medicines and possible side effects
6) report ADRs

Question 9

Identify patients at risk of ADRs

Answer 9

1) extremes of age
2) females > males
3) polypharmacy
4) incurrent diseases
5) a history of intolerance or hypersensitivity

Question 10

List the top 10 drugs known to produce ADRs (10)

Answer 10

1) NSAIDs
2) diuretics
3) warfarin
4) ACEIs/A2RAs
5) Antidepressants and lithium
6) beta-blockers
7) opioids
8) digoxin
9) perdnisolone
10) clopidogrel

Question 11

What are the 5ways the BNF classifies side effects (5)

Answer 11

1) very common : greater than 1-10
2) common : 1 in 100 to 1 in 10
3) uncommon/ less commonly: 1 in 1000 to 1 in 100
4) rare : 1 in 10000 to 1 in 1000
5) very rare : less than 1 in 10000

Question 12

Explain how you would counsel patients on side effects. (3)

Answer 12

• after you have dispensed a prescription you need to counsel a patient on the side effects
  1) find the information on the BNF , patient information leaflet
  2) only list the serious and common side effects
  3) the most important ones are the serious ones - counsel the patient without scaring them

Question 13

Before a new medicine is marketed , how many patients will have been treated with it?

Answer 13

1500- normal healthy individual

Question 14

Which reactions are likely to have been picked up form animal studies during clinical trials? (3)

Answer 14

1) diarrhoea
2) dry mouth
3) liver toxicity

Question 15

Explain why ADRs should be reported (3)

Answer 15

1) important mechanism for post-marketing surveillance of medicines
- limited drug safety information collected from clinical trials
- identify side-effects which may occur after long term use
2) vital for maintaining drug safety
3) professional responsibility to maintain patient safety

Question 16

Which drug was responsible for causing birth defects and deaths in pregnant women?

Answer 16

Thalidomide

• was marketed as outstandingly safe
• caused 8000 children in 46 countries to be born with deformities
• withdrawn from market and yellow card scheme introduced a few years after

Question 17

What is the aim of the yellow card scheme?

Answer 17

aim of the yellow card scheme is to improve patient safety by finding out as much as possible about adverse reactions by pooling health professionals and the publics experience and suspicions

Question 18

What is the information gathered from the yellow card scheme used for? (4)

Answer 18

1) provide early warning of unrecognised ADRs
2) identify predisposing factors
3) compare drugs in the same therapeutic class
4) continuously monitor the safety of all drugs

Question 19

Where can the yellow card scheme be found and who can report? (2)

Answer 19

1) BNF and mhra website
2) doctors and dentists, coroners, hospital/community pharmacists, nurses, optometrist , radiographers, members of the public

Question 20

How many ADRs are reported? (2)

Answer 20

1) 400,000 reports since 1964. Currently 20,000 reports a year
2) but only 2-4% of all ADRs are reported and only 10% of serious ADRs are reported

Question 21

What was the impact of the yellow card scheme (2)

Answer 21

1) rofecoxib -cox2 inhibitor
- 2004: voluntarily withdrawn from the market because of concerns about increased risk of heart attack and stroke associated with long-term, high dosage use
2) alendronic acid
- reports of covered oesophageal reactions
- results in warning and revised dosing instructions

Question 22

How would you identify ADRS (5)

Answer 22

A patient reports a symptom that:

1) appears soon after a new drug is started
2) appears after a dosage increase
3) disappears when the drug is stopped
4) reappears when a drug is restarted
5) changes in clinical measurements and lab results

Question 23

If you suspect an ADR what should you report? (6)

Answer 23

all drugs- report serious suspected adverse reactions :

1) fatal
2) life threatening
3) involves or prolongs inpatient hospitalisation
4) involves persistent or significant disability or incapacity
5) congenital abnormality
6) medically significant
- black triangle drugs report all suspected adverse reactions

Question 24

What are black triangle drugs? (2)

Answer 24

1) new drugs and vaccines which are being intensively monitored
- new drug
- new combination of drugs
- new route of administration/ delivery system
- new indication
2) complete list available from MHRA