Adverse Drug Reaction

Question 1

AN ADVERSE EVENT

Answer 1

defined as an injury caused by medical management rather than by the underlying disease or condition of the patient. An example of an adverse event is a patient using equipment to administer medicine that has been condemned or equipment/drugs being tampered with.

Question 2

AN ADVERSE DRUG REACTION

Answer 2

A reaction while taking a drug that is suspected to be caused by the drug or drugs. An example of an ADR could be a patient experiencing anaphylaxis shortly after taking the drug

Question 3

Common Adverse Drug Reactions

Answer 3

• Warfarin- Clexane, Heparin
• Diuretics- Furosemide
• Tranquillizers- benzodiazepines • Antibiotics
• Steriods
• Antihypertensive

Question 4

Type A Reaction

Answer 4

(pharmacological) can be predicted on the basis of the pharmacological actions of the drug and therefore are readily reversible on reducing the dose or withdrawing treatment with the drug

For example; Respiratory depression with opioids or bleeding with warfarin

Question 5

Type B Reaction

Answer 5

(idiosyncratic) cannot be predicted from the known pharmacology of the drug. These are less common, and so may only be discovered for the first time after a drug has already been administered.
For example; Anaphylaxis with penicillin or skin rashes with antibiotics

Question 6

Is Type A or B reactions more common?

Answer 6

Type A adverse reactions are more common than type B reactions and account for more than 80% of all reactions

Question 7

Type 1 (anaphylaxis) Reaction

Answer 7

• Reaction occurs within minutes of re- exposure to allergen.
• e.g. Histamine- causes increased permeability of capillaries resulting in oedema (swelling) and erythema (redness). Increased mucous secretion - first line defence against irritants in the lungs and smooth muscle contraction in respiratory bronchi (Passageways by which air passes through the nose or mouth) causing breathing difficulty.

Question 8

What causes anaphylaxis?

Answer 8

Food - nuts 
Drugs 
Antibiotics
Anaesthetic drugs
Other drugs
Drugs - latex and hair dye

Question 9

Type II: cytotoxic reactions

Answer 9

May affect a variety of organs and tissues.
• The reaction time is minutes to hours
• Transfusion reaction- Mainly ABO and rhesus system antigens.

Question 10

Type III: immune complex reaction

Answer 10

The reaction may take 3 - 10 hours after exposure to the antigen.
• The reaction may be general
• May cause malaise and fever, oedema, rashes, or may involve individual organs including skin (e.g. Systemic lupus, kidneys (e.g, Lupus nephritis), joints (e.g, Rheumatoid arthritis)

Question 11

Type IV: Delayed type reaction

Answer 11

The reaction takes two to three days to develop.

E.G, skin test reaction, poison ivy rash, detergent.

Question 12

Type E reactions

Answer 12

or‘end-of-use’reactions, are associated with the withdrawal of a medicine.

E.G. Is insomnia, anxiety, depression following the withdrawal of benzodiazepines, alcohol, chemotherapy drugs-

Seizures Rashes Headaches Nausea

Question 13

Yellow Card Scheme

Answer 13

Relies on reporting of suspected adverse drug reactions where there is a suspicion that there is a causal relationship between the medicinal product taken and the suspected reaction experienced.

Question 14

Signs & symptoms of ADRS

Answer 14

A red raised itchy skin rash
• Swelling of the lips, eyes and feet
• Narrowing of the airways = wheezing
• Sudden drop in blood pressure = faint and dizzy • Nausea
• Vomiting
• Sore, red itchy eyes
• Feeling of impending doom

Question 15

Management

Answer 15

Remove the trigger
• Adrenaline – 1:1000, 500mcg in 0.5ml IM, (can be given IV but only by
experienced specialists 50mcg)
• Fluid challenge – 500-1000ml crystalloid/colloid (avoid colloid if thought to be the reason for reaction).
• Antihistamine – chlorphenamine im or iv slow 10mg
• Hydrocortisone–IMorIVslow,200mg
• High flow oxygen