lecture 16 - adverse drug reactions Flashcards
define an adverse drug reaction (ADR)
- response to a drug which is noxious and unintended
- occurs at a dose normally used
- most reactions are mild, and severe reactions are rare
allergy
adverse reaction mediated by immune response
side-effect
expected and known effect of drug that is not intended outcome
medication errors
mishaps that occur during prescribing, transcribing, dispensing, administering, adherence, or monitoring a drug. More common than adverse drug events
different responses to ADRs
mild = no change in treatment required
moderate = requires change in treatment or additional treatment
severe = disabling, life-threatening, requires hospital admission; congenital abnormality
Classification of ADRs by ABC
- Type A (augmented; extension of pharmacologic effect)
- Type B (bizarre; rare and unpredictable; eg. allergies)
- Type C (associated with chronic use)
- Type D (delayed effect)
- Type E (effect resulting from end of treatment)
- Type F (failure of treatment; inadequate dosing)
time course of drug allergies
Immediate (within 1 hour):
• Type 1 Anaphylactic
Delayed (after 1 hour):
• Type 2 Cytotoxic
• Type 3 Immune complex
• Type 4 Cell-mediated
Classification of ADRs by DoTS
Dose: supra-therapeutic (toxicity) standard therapeutic, sub-therapeutic doses (hyper-sensitivity)
Timing: time independent and dependent
Susceptibility: reasons for hypersensitivity (genetic factors, age, sex, disease, etc.)
importance of ADRs
- 4th leading cause of death in US
- can cause death
- poorer patient experience
- greater cost to healthcare system
doctor based strategies for preventing ADRs
- avoid & be vigilant of high-risk drugs
- discontinue unnecessary drugs
- consider drugs as a cause of any new symptoms
- avoid treating side effects with another drug
- avoid drug-drug interactions
- adjust dose depending on age & creatinine CL
system based strategies for preventing ADRs
- pharmacist intervention
- computerized order entry
- electronic medication administration record
determination of ADRs
- investigate whether drug is known to cause section
- rule out alternatives (may be associated with worsening of condition, new medical problem)
- establish link between onset of reaction and drug administration
- can use probability assessment tool, eg. Naranjo Algorithm
course of action
- withdraw trigger medicine
- record suspected ADR in drug chart
- inform patient, caregiver, doctor
- complete CARM adverse drug reaction form
