Adverse drug reactions

Question 1

Discuss the frequency of Adverse Drug Reactions (ADRs)

Answer 1

4th cause of death in UK and US.
5% of admissions to hospital are due to ADRS.
10-20% of patients will suffer from an ADR in hospital.

Question 2

Define an ADR

Answer 2

ADR: any response to a drug which is noxious, unintended and used at doses for prophylaxis, diagnosis and treatment.

Question 3

Discuss the mechanisms and role of differing disease states in the occurrence of Type A ADRs.

Answer 3

• Differential diagnosis
• history of medication
• relate to dose and beginning of treatment
• lab tests ( plasma concentration, allergies)

Question 4

Discuss the methods available for detection and reporting of ADRs.

Answer 4

Yellow cards: reporting any abnormal reaction to a drug. Allow abnormal patterns to be detected.

Question 5

Onset and severity of ADR

Answer 5

Onset:
-acute: within 60 minutes - bronchoconstriction
-sub-acute: 1-24 hours- serum sickness/rash
-latent: over 2 days
Severity:
-severe : severe life threatening consequences
-Mild : may need to be hospitalised. doses reduced
-moderated: mild discomfort but no major changes required.

Question 6

Type A

Answer 6

Augumented- predictable
-pharmacokinetic/ pharmacodynamic/ pharmacogenetics/ prescription errors
e.g. bradychardia with beta blockers
hypoglycaemia with insulin

Question 7

Type B

Answer 7

Bizarre- unpredictable
Causes:
-Idiosynchratic- due to abnormal receptors/enzymes
-Allergy- first dose of drug acts as an antigen- antigen/antibody complexes formed
-Increased probability with Macromolecules (e.g. vaccines, proteins), HLA genes, asthma and eczema patients

Question 8

Type C

Answer 8

Chronic- semi-predictable

Osteoporosis- extended steroid treatment

Question 9

Type D

Answer 9

Delayed
Carcinogenesis
Teratogenesis- fetus congenital malformation relating to drugs taken during first trimester

Question 10

Type E

Answer 10

End of treatment
Addisons- end of steroid treatment
Epilepsy- withdrawal from alcohol
MI- beta blockers removed

Question 11

Type F

Answer 11

Failure of treatment

Question 12

Example of receptor abnormality and enzyme abnormality in type B

Answer 12

Receptor abnormality:
Malignany hyperthermia with anaestetics

Enzyme abnormality:
G6PD Deficiency- increased risk of red cell haemolysis when given primaquine