Drug Allergies and ADE Flashcards
what is an adverse drug reaction aka side effect
effects from the drug when it is administered correctly and at the right dose. NOT TO BE CONFUSED WITH MEDICATION ERRORS which are when someone did something wrong
some patients are more susceptible than others
Urticaria
hives
Erythema
redess on skin
angioedema
swelling/edema in deep cutaneous and mucosal tissue
Morbilliform
macular or maculopapular rash or both. looks like many mini red rashes on the skin in large patches, with heathy skin in between
What is in a med guide
FOR the patient, in layman terms, tells them what bad things can happen when using the drug, advises them on how they can use the drug safely, and what they can watch out for incase they need to see a doctor.
FDA approved patient handout. Considered part of the drugs labeling. the medguides need to be given out everytime the patient is getting the drug. (new rx and each refill)
All:
NSAIDS, antidepressants, antipsychotics, ADHD stimulants, anticonvulsants, long acting opioids, and amiodarone and some other antiarrhythmics are classes that require med guides for all of their drugs.
what is in a REMS guide
risk evaluation and management strategy - forces the health care provider to have special requirements before prescribing and the pharmacy before dispensing to ensure benefits outweigh the risks
Tells us that this drug has risks that have to be managed (ex: birth defects, must use contraception, isotrentinoin iPLEDGE, clozapine)
What is a type A reaction
this is predictable, dose dependent and related to the known actions of the drug. can occur in any patient. These are most common and the main reason for most ADRs
ex: Doxazosin causing orthostatic hypotension, because of this known effect, the dose is slowly titrated and taken at bedtime
Type B reactions
these are not dose dependent and are unrelated to the known actions of the drug. these are influenced by patient specific factors
ex:drug allergies, psuedoallergic rxns (vancomycin infusion rxn or itchiness with opioids, drug intolerance (ex: nausea with codeine), idiosyncratic reactions like SJS,
Whats the difference between all four types of drug allergies
Type 1 most common - IgE mediated, occurs within 60 minutes (ex: hives, bronchospasm, angioedema, anaphylaxis)
Type 2: antibody mediated, occurs 5-8 days after exposure (ex: thrombocytopenia, hemolytic anemia)
Type 3- immune complex reactions occuring 3-10 hours after drug exposure
Type 4 -cell mediated or delayed hypersensitivity reactions anytime from 48 hrs to several weeks after drug exposure (ex: SJS)
box warnings alert prescribers of or pharmacies of
death or permanent disability (ex: VTE ad death from stroke with raloxifene)
ex: do not dispense amp B doses of > 1.5 mg/kg because of deaths caused by doses 3-5 mg/kg
Contraindication vs warnings and precautions
Precaution/warning: risk benefit analysis that may not change prescribing decision (ex: raloxifene has risk of VTE)
CI: the drug CANNOT be used in the patient because the risks outweigh the benefit (ex: raloxifene in someone w previous VTE)
What is the Naranjo scale
the scale used to assessed whether the drug caused an ADR. if the score is > 9 definitely caused, 5-8 probable, 1-4 possible, 0- doubtful
Where should we report side effects, adverse events, and allergies
To the FDA medwatch program: FAERS (FDA adverse event reporting system)
This is voluntary reporting for the safety of patients. If we report to the manufacturer, they are then required to report to the FDA. The FDA may eventually require manufacturer to update labeling and issue a prescriber alert warning in the mean time.
Vaccines are an exception and are reported to the VAERS
What is a phase 4 trial
after a drug is marketed, the FDA might take hints from public after time to study the drug for a certain ADR. ex: fluconazole right now bc it may be linked to miscarriage in women who used for yeast infx.
Intolerance vs. Allergy
Intolerance: nausea and constipation, some itchiness- which can be treated with benadryl to help because sometimes its related to histamine but not allergic. Patients may not like the intolerance but that doesn’t mean we can never use it.
allergy: itching, systemic immune response - related to histamine, anaphylaxis, angioedema
Drugs that cause photosensitivity
amiodarone
diuretics
methotrexate
oral and topical retinoids
quinolones
st johns wort
sulfa antibiotics
tacrolimus
tetracyclines
voriconazole
remember, photosensitivity can spread even to parts of body that were not exposed to sun
MAKE SURE TO GIVE PATIENTS UV A AND UV B protection
counseling for patients on drugs that cause photosensitivity
dont go outside from 10 am - 4pm including on cloudy dates
wear sun protective clothing
SPF 30-40 broad spec. for UVA (causes aging) and UVB (causes burning)- anything higher than that just causes skin rxns. apply liberally every 2 hours and after getting wet.
Time to Burn formula
SPF person is using x 15 minutes( represents the usual time to burn TTB)= minutes. This number might be large, but the recommendation is to reapply every 2 hours anyway.
what is TTP (thrombocytopenic pupura) and what drugs are commonly associated with it
blood disorder where clots form throughout the body and lead to bleeding under the skin (forms purpura/bruises)
Oral P2Y12 inhibitors - ex: clopidogrel
Sulfamethoxazole
others: acyclovir, famcyclovir, valacyclovir
Petechiae vs. Echymoses
small lesions < 3 mm
larger lesions > 5 mm
hematoma
collection of blood under skin due to trauma to blood vessel and leaking to surrounding tissue
LMWH and heparin and other anitcoags. are examples of a drug that can cause this. do not rub after inj.
SJS and TEN and DRESS (life threatening skin rxns)
SJS (stevens-johnson syndrome) - can lead to TEN (Toxic epidermal necrolysis) occurs 1-3 weeks after drug. sometimes caused by OTC analgesics like Tylenol and ibuprofen in kids.
severe mucosal erosions and epidermal detachment and skin loss can occur (basically a third degree burn). fever, major fluid loss and organ damage. WE MUST PROVIDE FLUID AND ELECTROLYTE REPLACEMENT along with wound care and pain meds, and antibiotics
Drug reaction with eosinophilia and systemic symptoms - Difference: Rarely involves mucosa. can be a variety of skin reactions with systemic sx too like fever, hepatic dysfunction, renal dysfunction, lymphadenopathy. sx may continue for some time after stopping drug
True or false: we should NEVER use steroids with patients who have TEN, but we can use them for patients with SJS
true.
for a true drug allergy to occur, the drug must have been
taken previously.. people dont get drug allergies on their first time taking a medication. initial exposure= sensitization, second exposure = excessive histamine release and this is a type 1 hypersensitivity rxn
pseudoallergic or anaphylactoid reaction
fake allergy reaction that has no IgE response but clinical appearance and treatment seem like it
drug class we can use for swelling, itching, and rash
antihistamines
drug classes we can use for swelling
steroids
NSAIDS
Drug used to reverse bronchoconstriction
epinephrine
anaphylaxis
life threatening - within one hour of drug use, but can occur more rapidly. tx required immediately (lay them flat (nothing under neck or head to constrict airway, epinephrine, benadryl, steroids, IV fluids)
sx: hives, rash, difficulty breathing, wheezing, abdominal cramping, hypotension, dizziness, light headedness
Drugs associated with severe skin rxns
abacavir (gene test)
Allopurinol (gene test)
Carbamezapine (gene test)
ethosuximide
lamotrigine
modafinil
nevirapine
penicillins
phenytoin
sulfamethoxazole
other Epi pen brand names
Epi Pen, Epi pen Jr. AuviQ (comes with voice instructions), Symjepi
usually epinephrine 1 mg/ml in doses of 0.3 mg for adults or 0.15 mg for children 15-30 kgs.
patients with allergies should carry
epi pen
2 x 25 mg benadryl tablets (take only if no tongue or lip swelling)
emergency contact info
patients with allergies should carry
epi pen
2 x 25 mg benadryl tablets (take only if no tongue or lip swelling)
emergency contact info
how to administer epi pen autoinjectors
no need to remove clothing,. no need to refrigerate. make sure not expired.
remove case from pen
orange end contains the needle
hold pen firmly in whole fist . do not get your fingers close to needle because you could inject yourself and get necrosis or vasodilation.
inject into middle of outer thigh at 90 degrees and hold pen firmly in place for 3 seconds. remove needle and massage area for 10 seconds
orange tip should have covered the needle after removing injection but if not, dont reuse it. it is normal for a bit of liquid to remain in pen.
call 911
penicillins and sulfonamides cause the most true drug allergies
all beta lactams should be avoided if true penicillin allergy
true penicillin allergy occurs in 1% of people
On exam, assume true penicillin allergy. Exceptions:
- pregnant woman with syphillis, if allergic just desensitize her.
- peds with AOM with mild/nonsevere penicillin allergy can use cephalosporin
- Aztreonam is the only true exception for drugs that can be used in pts w/ penicillin allergy
all sulfa drugs (ex: sulfamethoxazole)
others: opioids, biologics, heparin,
NSAIDs including ASA- can cause breathing difficulty : watch in asthma pts because their pathway with prostaglandins interacts w breathing.
Drugs to avoid in peanut and soy allergies
Clevidipine (Cleviprex)
Propofol (Dipirivan)
Progesterone
drugs to avoid in pts with egg allergies
yellow fever vacc
clevidipine (cleviprex)
propofol (Dipirivan)
Influenza
what flu vaccines can pts take if they are allergic to egg
Flublok
Flucelvax Quadrivalent
if pt reacts severely to any flu vaccine including non egg forms, they should not receive any more doses of the vaccine in the future
True or false: we can do penicillin skin testing to identify pts at highest risk for type 1 hypersensitivity rxn, and we can desensitize pregnant women who need penicillin for syphillis tx
true
true or false: never try to desensitize a pt on a drug that caused them an SJS or TEN rxn in the past.
true
T or false: densensitizing a pt to a drug cures them from their allergy
false. it doesnt and so we should never remove it from their medical record.
