Adverse drug reactions Flashcards
(33 cards)
Adverse reaction
Harmful or seriously effects occurring at doses intended for therapeutic effect and which call for reduction of dose or withdrawal of the drug and/or forecast hazard from future administration
Type A vs B Reactions
- Type A reactions : 85-90% of all adverse drug reactions, can affect any individual, given sufficient dose and exposure, and are predictable from the known pharmacologic properties of a drug
- Type B or allergic drug reaction/hypersensitivity reaction: results from a specific immunologic response to a medication, 10-15% and occurs in a susceptible subgroup of patients, have signs and symptoms that are different from the pharmacologic actions of the drug, and usually cannot be predicted
______: implies a direct action of the drug, often at high dose.
Toxicity
Relative vs. types of special cases of toxicity
- Relative toxicity: an ordinary dose that may be toxic due to an underlying abnormality in the patient e.g. kidney disease
- Mutagenicity, carcinogenicity and teratogenicity are special cases of toxicity.
_____: a low threshold to the normal pharmacological action of a drug
Intolerance
______: an inherent qualitative abnormal reaction to a drug, usually due to a genetic abnormality e.g., porphyria-heme synthesis dysfunction.
Idiosyncrasy
______ : reactions which result in objectively
reproducible symptoms or signs initiated by exposure to a defined stimulus at a dose tolerated by normal subjects
Hypersensitivity
______: personal or familial tendency to develop IgE antibodies in response to low doses of allergens, and to develop typical symptoms e.g. asthma, rhinoconjuctivitis and eczema/dermatitis or tendency to develop allergies
Atopy
______: a hypersensitivity reaction initiated by immunological mechanisms
Allergy
______: a severe, life-threatening, generalized or systemic hypersensitivity reaction (subset of allergy)
Anaphylaxis
Adverse reactions cause ____% of consultations in general practice
2-3
Adverse reactions cause ___% of admissions to ICUs
3
Overall incidence in hospital in-patients due to adverse reactions is ____%
10-20
Adverse reactions cause prolonged hospital stay in ≈___% of patients in acute medical units
10
Deaths caused by ADR annually
100,000
Drug-induced Skin Reactions
– Maculopapular eruptions
– Urticarial rashes and angioneurotic edema
– Fixed drug eruptions
– Photosensitivity, phototoxicity and photoallergy
– Vasculitis
– Hyperpigmentation
– Drug-induced systemic lupus erythematosus
– Anticoagulant-induced skin necrosis
– Severe skin reactions
Drug-induced Pulmonary Reactions
- Bronchospasm -can precipitate asthma
- Drug-induced cough ACE-inhibitors
- Pulmonary edema
Blood Dyscrasias (reactions)
Thrombocytopenia
Granulocytopenia
Aplastic anemia
Hemolysis
Chronic organ toxicities that can occur due to ADRs
Eye: corneal opacities
Liver: cirrhosis
Kidney: nephropathy
Uterus: endometrial cancer
ADR’s effects in pregnancy
- Teratogens: in first trimester- alcohol, isotretinoin
- ↓ fetal bone and tooth development
- Ototoxicity
- Drugs given just prior to labor
vasoconstrictor-s↓fetal blood supply fetal distress - Drugs given during labour: diazepam- hypotonia in neonate and ↓ suckling
______ is the most common drug allergy
Penicillin
T/F Complaints of: nausea, vomiting, diarrhea,
headaches, general malaise, dizziness are examples of true allergic reactions
False - they are side effects of medication
- Not mediated by the immune response
- Not a contraindication to re-treatment with the
offending agent
- Mitigation: decrease rate of absorption, try food
or snack with oral medications
What are Pseudoallergic reactions?
- Direct stimulation of mast cells resulting in release of histamine (flushing) - Opiates, vancomycin (infuse-rate dependent)
- Non-immunologic activation of the complement cascade (Radiocontrast media)
- Change in metabolism or production of inflammatory mediators (ACE inhibitors, aspirin, NSAIDS)
Characteristics of true allergic reactions
- Mediated by immune response
- lnvolve lgE, or lgM and/or lgG antibodies, or T-cells
- Lead to mast cell degranulation and histamine release
- Present as hives, itching, angioedema, dyspnea, wheezing, anaphylaxis, severe hypotension
- May recur within or across drug classes due to ability of similar structural components between drugs to elicit similar antigenic responses (penicillins and cephalosporins)
- Contraindications to re-treatment with the offending agent and/or treatment with other similar drugs
