Drug allergies and ADR Flashcards
(ADR) Adverse Drug Reaction:
is a term that encompasses all UNINTENDED PHARMACOLOGIC EFFECTS of a drug when it is administered correctly and used at recommended doses.
Effects from a drug when it is administered CORRECTLY.
ADR are typically DOSE-RELATED; the ADR severity increases with higher doses/reduced renal clearance.
Medication Error:
can include overdose and administration mistakes.
Something WRONG occurred, such as giving a medication dose to the WRONG person.
Urticaria (hives):
a rash with red/pinkish raised patches. the patches have varied shapes and sizes.
Pruritus (itching):
any rash or reaction that causes itching can be referred to as pruritis.
Erythema:
redness on the skin from superficial (near the surface) capillaries, often due to inflammation with pruritis. When pressed down, the red skin will blanch (whiten) temporarily because the blood flow is blocked. erythematous refers to an area on the skin, such as a patch, with erythema.
Angioedema:
Swelling caused by edema in the deeper dermal, cutaneous and submucosal tissue.
Morbilliform:
Macular or maculopapular rash (or both), with 1-10 mm lesions and healthy skin between the lesions.
(ADR) Adverse Drug Reactions:
are categorized into 2 types:
1)
2)
1) (Type A) predictable
2) (Type B) unpredictable
(Type A) predictable
- Dose-dependent
- predictable based on the drug’s pharmacology, pharmacologic actions
- can occur in anyone
- ranges from mild to severe
- ## most common, account for 80% of ADRs
ex. orthostatic hypotension with doxazosin, because of this risk, the dose of the medication should be slowly titrated.
(Type B) unpredictable
- NOT dose -dependent
- idiosyncratic: NOT predictable from drug’s pharmacology
- can be influenced by patient specific factors
Type B reactions include:
Drug allergies
Pseudoallergic reactions
Idiosyncratic reactions
ex. SJS
Type I Reactions:
IgE-mediated and immediate, within 60 minutes of drug exposure, ranging from minor local reactions to severe systemic reactions.
ex. urticaria, bronchospasm, angioedema, anaphylaxis,
Type II Reactions:
Antibody-mediated, occurring several days (usually 5-8 days) after drug exposure.
ex. hemolytic anemia, thrombocytopenia
Type III Reactions:
Immune Complex reactions, occurring > greater than or equal to 1 week after drug exposure.
ex. drug induced lupus erythematosus
Type IV Reactions:
Cell-mediated or delayed hypersensitivity reactions, occurring anytime from 48 hours to several weeks after drug exposure.
ex. Stevens-Johnson syndrome
Type I Reactions:
- occur right after drug has been taken, immediate (within 15-30 minutes of drug exposure).
- so, if taken orally, may take a little longer because drug has to get digested and be exposed to blood
- IgE-mediated allergic reaction
- severity ranges from minor inconvenience to death
- mostly due to Histamine release from basophils
- urticaria (hives), angioedema
Type II Reactions:
- minutes to hours after drug exposure
-ex. hemolytic anemia, thrombocytopenia (platelet count down a lot)
Type III Reactions:
- they occur 3-10 hours after drug exposure
-ex. drug-induced lupus and serum sickness
Type IV Reactions: “Delayed hypersensitivity reactions”
- they can take anywhere from 48 hours to several weeks after drug exposure.
- PPD skin test for tuberculosis, which peaks at 48-72 hours
- a lot are injectables
histamine comes from 2 types of cells:
- basophils
- mast cells