Drug allergy

Question 1

Type 1 hypersensitivity

Answer 1

immediate
IgE mediated
Ex:
- anaphylaxis
- angioedema
- bronchospasm
- urticaria

Question 2

Type 2 hypersensitivity

Answer 2

Delayed: 5-8 days
IgG & IgM mediated
Ex:
- hemolytic anemia
- thrombocytopenia

Question 3

Type 3 hypersensitivity

Answer 3

Delayed (1 week or later)
IgG & IgM mediated
Ex:
- serum sickness
- drug induced lupus

Question 4

Type 4 hypersensitivity

Answer 4

Delayed (48 hrs to weeks)
T-cell mediated
Ex:
- SJS/TENs
- DRESS
- Contact dermatitis
- PPD test

Question 5

Drugs that require med guides

Answer 5

NSAIDs
antidepressants
antipsychotics
anticonvulsants
long-acting opioids (part of REMs)
Amiodarone & other antiarrhythmics

Question 6

High risk drugs for photosensitivity

Answer 6

Amiodarone
Diuretics (thiazide & loop)
Oral & topical retinoids
Methotrexate
Tacrolimus
Quinolones
Tetracyclines
Sulfa drugs
Voriconazole
St. John’s wort

Question 7

High risk drugs for severe cutaneous reactions

Answer 7

Allopurinol
Amoxicillin
Ampicillin
Vancomycin
Sulfamethoxazole
Sulfasalazine
Lamotrigine
Carbamazepine
Phenytoin
Ethosuximide
Nevirapine

Question 8

Papules

Answer 8

raised spots

Question 9

Macules

Answer 9

flat spots

Question 10

Purpura

Answer 10

red/purple spots due to bleeding under skin

Question 11

Petechiae

Answer 11

Small purpura spots (< 3mm)

Question 12

Ecchymosis

Answer 12

Larger purpura spots (> 5 mm)

Question 13

Hematoma

Answer 13

Collection of blood under skin

Question 14

Thrombotic Thrombocytopenic Purpura (TTP)

Answer 14

Drug induced clotting throughout the body
treat immediately with plasma exchange
High risk drugs:
- P2Y12 inhibitors (clopidogrel, prasugrel, ticagrelor)
- sulfamethoxazole

Question 15

SJS/TEN treamtent

Answer 15

stop offending drug
fluids & electrolytes
wound care
pain meds

steroids are controversial in SJS
they are CI in TENs

Question 16

Treating anaphylaxis

Answer 16

Pruritis & hives only:
- antihistamines

More severe rxn:
- epinephrine to open airways
- steroids
- antihistamine
- IV fluids

Question 17

Epinephrine adult & pediatric dosing

Answer 17

Adult: 0.3 mg
Pediatric: 0.15 mg

Question 18

Epinephrine administration

Answer 18

• pull off blue safety release
• keep thumb and fingers away from the orange (needle) end of the device
• inject into outer thigh, push until it clicks
• hold for 3 seconds
• remove needle & massage area for 10 seconds
• second dose with new injector can be given in opposite leg if needed before help arrives

Question 19

Epinephrine counseling points

Answer 19

• it is normal to see liquid remaining after injecting
• call for emergency help
• refrigeration is not required
• all products can be injected through clothing
• check device periodically to make sure medication is clear and not expired

Question 20

Beta lactam allergy

Answer 20

True penicillin allergy -> avoid all drugs in class

Cephalosporins have a very low risk of cross-reactivity. But for the NAPLEX, do not use in pts with penicillin allergy.

Question 21

Sulfa allergy: drugs to avoid

Answer 21

• Sulfamethoxazole
• sulfasalazine
• sulfadiazine

Warnings/CI:
- thiazide diuretics
- loop diuretics (except ethacrynic acid)
- sulfonylureas
- acetazolamide
- zonisamide
- celecoxib
- darunavir

Question 22

Peanut and Soy allergy

Answer 22

Palforiza- PO immunotherapy to mitigate allergic reactions to peanuts (inc anaphylaxis)

Soy & peanuts have cross reactivity

Meds contraindicated with soy allergy:
- Clevidipine (Cleviprex)
- Propofol (Diprivan)

Question 23

Egg allergy

Answer 23

True allergy -> CI with:
- clevidipine (Cleviprex)
- propofol (diprivan)

Patients with severe egg allergy can still get flu shot

Shots without egg:
- Flublok
- Flucelvax