77. Drug Allergies + ADRs Flashcards
T/F: Type B reactions are most common and account for an estimated 85% of ADRs
False - Type A
___ reactions are dose-dependent, related to the known pharmacologic properties of the drug
Type A
___ reactions are not dose-dependent, are unrelated to pharmacologic actions of the drug, and can be influenced by patient-specific factors (e.g. genetics)
Type B
Give 3 examples of Type B reactions
Drug allergies
Drug hypersensitivity reactions (DHRs)
Idiosyncratic reactions (genetic differences)
Describe Types of Drug Allergies: Type 1 Reactions - Immediate
Immediate, IgE-mediated, ranging from minor local reactions to severe systemic reactions
Examples: urticaria, bronchospasm, angioedema, anaphylaxis
Describe Types of Drug Allergies: Type II Reactions - Delayed
Antibody-mediated, usually 5-8 days after exposure
Examples: hemolytic anemia, thrombocytopenia
Describe Types of Drug Allergies: Type III Reactions - Delayed
Immune-complex reactions, occurring ≥ 1 week after exposure
Example: serum sickness
Describe Types of Drug Allergies: Type IV Reactions - Delayed
T cell-mediated, occurring 48 hours to weeks after exposure
Example: SJS
Key Drugs a/w Photosensitivity
Amiodarone
Diuretics (thiazide and loop)
Methotrexate
Oral and topical retinoids
Quinolones
St. John’s wort
Sulfa drugs
Tacrolimus
Tetracyclines
Voriconazole
____ is a blood disorder in which clots form throughout the body.
Thrombotic thrombocytopenic purpura (TTP)
What is the difference between papules vs macules vs purpura vs petechiae
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
What are common drugs that can cause TTP?
oral P2Y12 inhibitors (e.g. clopidogrel) and sulfamethoxazole
Define ecchymosis
Large bruised area
Define hematoma
A collection of blood under the skin d/t trauma (injury) to a blood vessel, resulting in blood leaking into surrounding tissue
____ is used to reverse bronchoconstriction if the patient is wheezing or has other signs of trouble breathing
Epinephrine
___ 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.
Opioids
___ 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.
Vancomycin
Patients positive for ___ are at an increased risk for abacavir hypersensitivity
HLA-B*5701
List 3 examples of severe cutaneous adverse reactions (SCARs)
Stevens-Johnson syndrome (SJS)
Toxic epidermal necrolysis (TEN)
Drug reaction with eosinophilia and systemic symptoms (DRESS)
Key drugs a/w with severe cutaneous adverse reactions (SCARs)
Allopurinol
Amoxicillin
Ampicillin
Carbamazepine
Ethosuximide
Lamotrigine
Nevirapine
Phenytoin
Sulfamethoxazole
Sulfasalazine
Vancomycin
Systemic steroids are contraindicated with ___ but may be used for SJS, though the benefit is controversial
TEN
T/F: A history of SJS/TEN to a medication is a contraindication to receiving it again
True
____ is a severe, life-threatening allergic reaction that usually happens within 1 hour of drug exposure, and involves multiple organs
Anaphylaxis
What are some examples of s/sx of anaphylaxis
Urticaria (hives)
Swelling of mouth/throat
Difficulty breathing or wheezing sounds
Severe GI symptoms (repetitive vomiting, severe abdominal cramping)
Hypotension
Anaphylaxis treatment
Epinephrine injection ± diphenhydramine ± steroids ± IV fluids
List of Drugs to Avoid in Sulfa Allergy
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
Common types of hypersensitivity reactions with aspirin and NSAIDs use
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
T/F: Peanuts and soy allergies can have cross-reactivity
True
Drugs contraindicated with soy allergy
Clevidipine (Cleviprex)
Propofol (Diprivan)
Drugs contraindicated with egg allergy (true allergy)
Clevidipine (Cleviprex)
Propofol (Diprivan)
Yellow fever vaccine
Which flu vaccines do not contain egg protein?
Flublok
Flucelvax
T/F: if a severe reaction to an influenza vaccine occurs, the patient can try a different vaccine next time
False, the pt should not receive further doses of any influenza vaccine
T/F: it is not recommended to administer flu vaccine to patients with severe egg allergy
False - ACIP states pts who have had severe symptoms when consuming eggs can receive any indicated inactivated vaccine
What is the goal of penicillin skin testing?
To identify patients who are at the greatest risk of a type I hypersenstivity reaction if exposed to a systemic penicillin
What determines positive penicillin skin testing?
If there is a localized reaction around the test sit larger than negative control
When is penicillin skin testing not allowed?
For severe delayed reactions like SJS or TEN
Only to be used for IgE-mediated reactions
What is an example for when desensitization would be used for penicillin?
Pregnant with penicillin allergy and has syphilis - CDC recommends desensitization and penicillin treatment
T/F: If a patient is successfully desensitized to a medication, providers should take off the allergy from their profile
False
When is desensitization not allowed?
If drug previously caused SJS or TEN
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
True - this is called delabeling
What is the naranjo scale?
Naranjo Scale helps determine the likelihood that a drug caused the adverse reaction (higher the score = more likely)
REMS are developed by ____ to ensure the benefits of a drug outweigh the risks
The manufacturer - approved by FDA
What drugs have REMS programs?
Clozapine
Isotretinoin (Accutane)
What are medication guides?
FDA-approved patient handouts that detail a drug’s important adverse events in non-technical language (considered part of drug’s labeling)
T/F: Medication guides are considered a part of drug’s labeling
True
If a medication has a MedGuide, when should it be dispensed with the med?
With original rx and with each refill
(Not necessary for inpatient given close monitoring but can be given upon request)
