Adverse Drug Reactions

Side effect

a desirable or undesirable effect that is secondary to the intended effect of the drug

A side effect can be...

good or bad

adverse drug reaction

any unexpected, unintended, undesired, or excessive response to a medication given at therapeutic dosages

Type A adverse drug reactions

exaggerated, but otherwise expected pharmacological effect of a drug

predictable and dose dependent

Type B adverse drug reactions

not expected reactions, drug allergies and hypersensitivities

Pseudo allergy

adverse reaction that looks like allergy but is not

Pharmacologic interaction with immune receptors

dose dependent, drug bonds with receptor proteins to form antigen

Hypersensitivity Type I

Immediate drug reaction mediated by IgE & mast cells and/or basophils

What are symptoms seen with Type I hypersensitivities?

wheezing, GI upset, rash, urticaria, hypotension, angioedema

What drug classes tend to cause Type I hypersensitive reactions?

Beta lactams, quinolones

A patient presents with a type I reaction. What is the best way to immediately treat them?

EPI

Type II hypersensitivity

delayed drug reaction caused by antibody mediated cell destruction, cytotoxic

What types of conditions are seen with Type II hypersensitivities?

Blood conditions: hemolytic anemia, thrombocytopenia, neutropenia

What drug can cause Type II hypersensitivities?

Propylthiouracil (PTU)

Type III hypersensitivity

delayed drug reaction caused by IgG-drug immune complex deposition and complement activation

Type III hypersensitivity symptoms

hives, rash, fever, polyarthralgia / polyarthritis

Drugs than can cause Type III hypersensitivity

antitoxins, antivenoms, monoclonal antibodies

Type IV hypersensitivity

Delayed response mediated by T cells.

Stevens-Johnson syndrome

A severe, possibly fatal reaction that mimics a burn; a type IV sensitivity

toxic epidermal necrosis

A very dangerous condition that presents as a widespread epidermal necrosis, resembling a massive 3rd degree burn.

How much more likely are adverse drug reactions in the geriatric population?

twice