77. Drug Allergies + ADRs

Question 1

T/F: Type B reactions are most common and account for an estimated 85% of ADRs

Answer 1

False - Type A

Question 2

___ reactions are dose-dependent, related to the known pharmacologic properties of the drug

Answer 2

Type A

Question 3

___ reactions are not dose-dependent, are unrelated to pharmacologic actions of the drug, and can be influenced by patient-specific factors (e.g. genetics)

Answer 3

Type B

Question 4

Give 3 examples of Type B reactions

Answer 4

Drug allergies
Drug hypersensitivity reactions (DHRs)
Idiosyncratic reactions (genetic differences)

Question 5

Describe Types of Drug Allergies: Type 1 Reactions - Immediate

Answer 5

Immediate, IgE-mediated, ranging from minor local reactions to severe systemic reactions
Examples: urticaria, bronchospasm, angioedema, anaphylaxis

Question 6

Describe Types of Drug Allergies: Type II Reactions - Delayed

Answer 6

Antibody-mediated, usually 5-8 days after exposure
Examples: hemolytic anemia, thrombocytopenia

Question 7

Describe Types of Drug Allergies: Type III Reactions - Delayed

Answer 7

Immune-complex reactions, occurring ≥ 1 week after exposure
Example: serum sickness

Question 8

Describe Types of Drug Allergies: Type IV Reactions - Delayed

Answer 8

T cell-mediated, occurring 48 hours to weeks after exposure
Example: SJS

Question 9

Key Drugs a/w Photosensitivity

Answer 9

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

Question 10

____ is a blood disorder in which clots form throughout the body.

Answer 10

Thrombotic thrombocytopenic purpura (TTP)

Question 11

What is the difference between papules vs macules vs purpura vs petechiae

Answer 11

Papules are raised spots
Macules are flat spots
Purpura are red/purple skin spots (lesions) d/t bleeding underneath the skin (small and large spots)
Petechiae are pinpoint in size

Question 12

What are common drugs that can cause TTP?

Answer 12

oral P2Y12 inhibitors (e.g. clopidogrel) and sulfamethoxazole

Question 13

Define ecchymosis

Answer 13

Large bruised area

Question 14

Define hematoma

Answer 14

A collection of blood under the skin d/t trauma (injury) to a blood vessel, resulting in blood leaking into surrounding tissue

Question 15

____ is used to reverse bronchoconstriction if the patient is wheezing or has other signs of trouble breathing

Answer 15

Epinephrine

Question 16

___ can cause a non-IgE-mediated release of histamine from mast cells in the skin, causing itching and hives. This is often when this drug is given to patients who have never used it before or given at higher than normal doses. Pre-medication may be required.

Answer 16

Opioids

Question 17

___ can cause a direct release of histamine from cutaneous mast cells, causing flushing, hives, and sometimes hypotension is infused too rapidly. Can be avoided by slowing infusion rate.

Answer 17

Vancomycin

Question 18

Patients positive for ___ are at an increased risk for abacavir hypersensitivity

Answer 18

HLA-B*5701

Question 19

List 3 examples of severe cutaneous adverse reactions (SCARs)

Answer 19

Stevens-Johnson syndrome (SJS)
Toxic epidermal necrolysis (TEN)
Drug reaction with eosinophilia and systemic symptoms (DRESS)

Question 20

Key drugs a/w with severe cutaneous adverse reactions (SCARs)

Answer 20

Allopurinol
Amoxicillin
Ampicillin
Carbamazepine
Ethosuximide
Lamotrigine
Nevirapine
Phenytoin
Sulfamethoxazole
Sulfasalazine
Vancomycin

Question 21

Systemic steroids are contraindicated with ___ but may be used for SJS, though the benefit is controversial

Answer 21

TEN

Question 22

T/F: A history of SJS/TEN to a medication is a contraindication to receiving it again

Answer 22

True

Question 23

____ is a severe, life-threatening allergic reaction that usually happens within 1 hour of drug exposure, and involves multiple organs

Answer 23

Anaphylaxis

Question 24

What are some examples of s/sx of anaphylaxis

Answer 24

Urticaria (hives)
Swelling of mouth/throat
Difficulty breathing or wheezing sounds
Severe GI symptoms (repetitive vomiting, severe abdominal cramping)
Hypotension

Question 25

Anaphylaxis treatment

Answer 25

Epinephrine injection ± diphenhydramine ± steroids ± IV fluids

Question 26

List of Drugs to Avoid in Sulfa Allergy

Answer 26

Sulfamethoxazole, sulfasalazine, sulfadiazine Thiazide diuretics, loop diuretics (except ethacrynic acid) Sulfonylureas Acetazolamide Zonisamide Celecoxib Cidofovir, darunavir, fosamprenavir, tipranavir Note: sulfite or sulfate allergies do not cross-react with sulfonamides

Question 27

Common types of hypersensitivity reactions with aspirin and NSAIDs use

Answer 27

respiratory (asthma, rhinorrhea) and urticaria/angioedema Note: up to 20% of patients with asthma are sensitive to aspirin and other NSAIDs - avoid in pts with hx of asthma, nasal polyps, and prior respiratory reactions to NSAIDs

Question 28

T/F: Peanuts and soy allergies can have cross-reactivity

Answer 28

True

Question 29

Drugs contraindicated with soy allergy

Answer 29

Clevidipine (Cleviprex) Propofol (Diprivan)

Question 30

Drugs contraindicated with egg allergy (true allergy)

Answer 30

Clevidipine (Cleviprex) Propofol (Diprivan) Yellow fever vaccine

Question 31

Which flu vaccines do not contain egg protein?

Answer 31

Flublok Flucelvax

Question 32

T/F: if a severe reaction to an influenza vaccine occurs, the patient can try a different vaccine next time

Answer 32

False, the pt should not receive further doses of any influenza vaccine

Question 33

T/F: it is not recommended to administer flu vaccine to patients with severe egg allergy

Answer 33

False - ACIP states pts who have had severe symptoms when consuming eggs can receive any indicated inactivated vaccine

Question 34

What is the goal of penicillin skin testing?

Answer 34

To identify patients who are at the greatest risk of a type I hypersenstivity reaction if exposed to a systemic penicillin

Question 35

What determines positive penicillin skin testing?

Answer 35

If there is a localized reaction around the test sit larger than negative control

Question 36

When is penicillin skin testing not allowed?

Answer 36

For severe delayed reactions like SJS or TEN Only to be used for IgE-mediated reactions

Question 37

What is an example for when desensitization would be used for penicillin?

Answer 37

Pregnant with penicillin allergy and has syphilis - CDC recommends desensitization and penicillin treatment

Question 38

T/F: If a patient is successfully desensitized to a medication, providers should take off the allergy from their profile

Answer 38

False

Question 39

When is desensitization not allowed?

Answer 39

If drug previously caused SJS or TEN

Question 40

T/F: When allergies are found to be disproven (by skin testing, drug challenge, or otherwise), providers should take off the allergy from their profile

Answer 40

True - this is called delabeling

Question 41

What is the naranjo scale?

Answer 41

Naranjo Scale helps determine the likelihood that a drug caused the adverse reaction (higher the score = more likely)

Question 42

REMS are developed by ____ to ensure the benefits of a drug outweigh the risks

Answer 42

The manufacturer - approved by FDA

Question 43

What drugs have REMS programs?

Answer 43

Clozapine Isotretinoin (Accutane)

Question 44

What are medication guides?

Answer 44

FDA-approved patient handouts that detail a drug's important adverse events in non-technical language (considered part of drug's labeling)

Question 45

T/F: Medication guides are considered a part of drug's labeling

Answer 45

True

Question 46

If a medication has a MedGuide, when should it be dispensed with the med?

Answer 46

With original rx and with each refill (Not necessary for inpatient given close monitoring but can be given upon request)