ADRs Flashcards
to be rational, drug therapy must include consideration of (3)
drug, host and disease factors
a goal of successful drug therapy is to achieve effective _____________ of ___________________ at __________________ in __________________
concentrations; the appropriate drug; the site of drug action; the individual
most drug therapies are based on
fixed dosage regimens
what are some host factors that would necessitate adjusting the dosage regimen
neonatal patient, geriatric patient, pregnant/lactating patient, species/breeds
what are some disease factors that would necessitate adjusting the dosage regimen
renal disease, hepatic disease, cardiovascular disease
what are some drug factors that would necessitate adjusting the dosage regimen (think broad)
pharmaceutical interactions, pharmacokinetic interactions, pharmacodynamic interactions
what is an ADR
unintended and usually noxious response to a drug that is unwanted
T/F ADRs occur at drug doses used for prophylaxis, treatment, or diagnosis
T
An estimated _____________ percentage of all hospitalized human patients are admitted due to an ADR
3-5%
what are the 6 most common drug classes to produce ADRs
1) NSAIDS
2) vaccines
3) antimicrobials
4) ectoparasitides
5) antihelmintics
6) anesthetic agents
what are the two types of ADRs? which is avoidable?
Type A and Type B; Type A is avoidable
what is the most common type of ADR
Type A
what are 3 characteristics of Type A ADRs
dose-dependent and predictable; experimentally reproducible; mechanism responsible is known
why do Type A ADRs alter plasma drug levels
change in the drug disposition (absorption, distribution, metabolism, excretion)
what are the 2 subtypes of Type A ADRs
pharmacological, intrinsic
describe pharmacological Type A ADRs
exaggerated pharmacological effects of the drug due to too much of the drug on its intended target receptor, or an off-target receptor (the right receptor in the wrong location)
an example of pharmacological type A ADRs is
propanolol (induced bradycardia in patients with higher than expected blood levels)
xylazine-induced emesis, propanolol-induced bronchospasm, and NSAID induced GI ulcers are examples of
Type A pharmacological ADRs due to off-target effects
describe intrinsic Type A ADRs
determined by the drugs physio-chemical properties, binding of metabolites to non-specific targets that disrupts organelles and membranes, nucleic acids and proteins
T/F pharmacological Type A ADRs are often dependent on bioactivation
F; intrinsic Type A ADRs are
the site of Type A intrinsic ADRs is dependent on (3)
cells/tissues that accumulate drug, location of metabolizing NZs, susceptibility of tissues
describe Type B ADRs
dose independent and unpredictable; not experimentally reproducible; host dependent
what are the two subtypes of Type B ADRs
immunological and idiosyncratic
what is the main form of Type B ADRs
immunological
describe immunological Type B ADRs
the drug (or metabolite) acts as a hapten on endogenous molecules, inciting type I-IV reactions
penicillin-induced allergies in dogs are what type of ADR
immunological Type B ADRs
how are intrinsic and idosyncratic ADRs similar
they usually involve bioactivation of the drug
describe idiosyncratic Type B ADRs
mechanism of action is usually unrelated to the pharmacologic action, or is unknown; involves bioactivation and depends on the chemical property of the drug
oral diazepam in cats and carprofen in dogs are examples of
Type B idiosyncratic ADRs
clinical signs of an ADR are usually _____________ and rarely ___________________
non-specific; pathognomonic
we diagnose ADRs based on
strength of association
systemic effects are often seen with Type A or Type B ADRs
Type B
T/F use of corticosteroids for all ADRs is well documented
F; only good for immunologic ADRs
the most important step when treating an ADR is __________________; the rest of treatment is based on ________________ and _________________
drug withdrawal; clinical manifestation of the drug; supportive care
In Canada, ADRs are reported on a (voluntary/involuntary) basis
voluntary
most clinically significant ADRs are due to ___________________ in the target species
altered drug disposition
what are some species differences that can lead to an ADR (4)
1) GI tract
2) body composition
3) blood volume
4) drug metabolism
what are some differences between geriatric and neonatal patients that can predispose to an ADR
geriatric: diminished organ function, altered body composition
neonatal: increased bioavailability, larger Vd, slower elimination
the most profound changes in drug disposition are found with a decline in what organ function
renal function
give 3 reasons why the kidneys are highly vulnerable to ADRs
1) kidneys receive 20-25% of cardiac output
2) kidneys concentrate drugs and toxins
3) kidneys have high metabolic activity
T/F uremia can reduce protein binding and hepatic metabolism of some drugs
T
you have a patient with CRF; what are 3 considerations when prescribing this patient medications
1) avoid drugs eliminated by the kidneys
2) avoid drugs that are toxic to the kidneys
3) dose adjustment
what 2 classes of drugs are capable of renal ADRs
NSAIDs, aminoglycosides
you have a patient with cardiac disease; what are 3 considerations before giving this patient medications
1) give critical drugs IV
2) give toxic drugs IV slowly
3) dose adjustments
what are 3 consequences of liver disease that can predispose to ADRs
1) reduced renal blood flow
2) reduced enzyme function
3) increased fraction of plasma unbound drug
you have a patient with liver disease; what are 3 considerations before prescribing this patient medication
1) dose adjustments
2) choose drugs that are mainly eliminated not by the liver (i.e. not in bile)
3) avoid the liver when possible
what is a drug interaction
change in the magnitude or duration of a pharmacologic effect of a drug due to the presence of another drug, food or environment factor
T/F drug interactions can occur before or after the drug is absorbed by the host
T
drug interactions are classified as (3)
pharmaceutical, pharmacokinetic, pharmacodynamic
pharmaceutical interactions occur __________________ and can be classified as (3)
before the drug is absorbed by the host; drug-drug; drug-diet; drug-environment
what is the most common type of drug interaction
pharmacokinetic
pharmacokinetic interactions depend on
changes in drug disposition
pharmacodynamic interactions occur when
one drug directly alters the physiologic or cellular response to another drug
pharmacodynamic interactions can be further classified as (3)
receptor interactions; post-receptor interactions; physiologic response interaction
