Drug Allergies Flashcards
drug allergy
a drug allergy is an adverse drug reaction that results from a specific immunologic response to a medication.
Identify the symptoms of a true drug allergy
hives; a rash; difficulty breathing, speaking, or swallowing; wheezing; and severely low blood pressure (hypotension) and severe allergic reaction also referred to as anaphylaxis
Type I drug allergy reactions onset, mechanism, and symptoms/manifestations
immediate onset
mediated by IgE
symptoms: rash, pruritus, flushing, angioedema, wheezing, GI symptoms, hypotension, anaphylaxis is most severe.
Commonly associated w.: beta-lactam antibiotics (penicillins and cephalosporins) and quinolones
Type II drug allergy reactions onset, mechanism, and symptoms/manifestations
delayed onset
IgG mediated
symptoms: hemolytic anemia, drop in platelets / WBCs
uncommon
Type III drug allergy reactions onset, mechanism, and symptoms/manifestations
delayed onset
IgG mediated
symptoms: serum sickness and vasculitits
Type IV drug allergy reactions onset, mechanism, and symptoms/manifestations
delayed onset
T-cell mediated
usual manifestion is skin: contact dermatitis, maculopapular eruptions, SDRIFE, drug fever, DRESS, stevens-johnson syndrome
common source of food allergies
o Egg, milk, wheat, peanuts, and gelatin
o Shellfish, tree nuts, peanuts, and fish
common source of dye allergies
o FD&C Yellow No. 5 (tartrazine), Yellow No. 6, Yellow No. 10
o Blue No. 1 and No. 2
o Red No. 40
common source of preservative allergies
o Sulfites
o Benzalkonium chloride
common source of latex allergies
o Injectable vial stoppers contain latex
o prefilled syringe tip cap
o latex gloves
people at risk for an allergic drug reaction
- People who have an allergy to one drug are more likely to have reactions to other drugs
- Drug allergies occur more often in women and young and middle-aged adults
- Certain genetic make-ups are more susceptible
- People with a family history of drug allergy may be at greater risk
- People with HIV or a history of Epstein-Barr virus (the one that causes mono) are at greater risk
- Increased exposure can increase the risk of drug allergy
cross-reactivity
People who are allergic to a drug may also have allergic reactions to drugs that share a similar chemical structure
CYP 450 enzymes
essential for the metabolism of many medications
drugs that induce CYP 450 enzymes
o Induction increases metabolism of drugs metabolized by this system
o Induction of metabolism leads to a reduction in pharmacologic action and potential treatment failure
drugs that inhibit CYP 450 enzymes
o Inhibiting enzyme action leads to a decrease in metabolism of drugs metabolized by a particular enzyme systems
o Decreased metabolism leads to the drug being available longer and an increase in pharmacological action.