MMT: principles of therapeutics and adverse drug reactions Flashcards
Explain and interpret data presented in Dose-Percent Curves
(A) Too little drug, no effect – a sub-effective dose
(B) Threshold effect and threshold dose, i.e. a minimally effective dose
(C) The plot shows a graded response – increasing dose increases the intensity of effect from point (B) up to point (D). The effect is said to be dose-dependent.
(D) Ceiling effect, or maximal effect. A higher dose does not increase effect. This is the response to a maximally effective dose. (Note: the only way to tell if you have reached maximum response is to increase the dose until you get no further increase in response.)
What is a frequency distribution curve?
Plots the percent of subjects who experience a predefines response to a dose of a drug
What is a cumulative frequency curve?
Expresses how many subjects have responded to a given dose or lower
Explain how Dose-Percent curves are used to estimate drug safety (therapeutic index).
Ld50/Ed50 = Theraputic index. the ratio is looked at to determine how safe the drug is. the higher the ratio, the safer the drug.
Define ED 50 , LD 50 and TD 50 in the context of Therapeutic Index.
ED50: dose at which half of participants responded
Ld50: dose at which half of animal subjects died
Td50: dose at which half the subjects experience a toxic effect
Therapeutic index: ld50/ed50….the larger the ratio the safer the drug
Compare and contrast ED50 in dose-response curves vs frequency distribution curves
In frequency distribution, ed50 represents the median effective dose. In dose-response it is the dose at which half-max effect is achieved.
List the many origins (types) of adverse drug reactions.
hypersensitivity, non-receptor mediated, idiosyncratic, drug-drug
Explain the significance of the designation of a compound as a prescription drug, over-the-counter drug or herbal supplement.
- prescription drugs: need FDA approval and prescription from a provider
- over-the-counter: needs FDA approval but can be acquired without prescription
- can buy anywhere; herbal supplements/dietary supplements do not need FDA approval
Explain what is referred to when using the terms FDA approval, “Off-Label” drug use and “Black Box Warnings.”
Black box: specific points of concern with taking the medication. Ex includes increased suicidal thought risk with antidepressants
Off label: ways to use FDA approved drugs in ways other than what they are approved for. Ex: using trazadone as a sleep aid. It is not FDA approved for insomnia, but there is evidence to support it helps.
FDA approval: given for a specific indication
Explain the significance of the Schedule of Controlled Substances.
show the relationship between drugs in use and their abuse potential
Schedule I: drugs with no currently accepted medical use that have a high abuse potential. typically only used in research
Schedule II: drugs with a high abuse potential that currently have accepted uses. they have a high potential for dependance.
Schedule III: less accepted medical use but less abuse potential than I and II.
Schedule IV: have accepted medical use and less abuse potential than I, II, and III
Schedule V: have accepted medical use and less abuse potential than I-IV
- Explain how fetal risk is characterized in drug information.
Category A: human studies have failed to demonstrate a risk to the fetus in the first trimester, and there is no evidence of risk in later trimesters. this is pretty rare.
Class B: animal reproduction studies have failed to demonstrate a risk to the fetus
Class C: show risk in animals, with little human data. Most drugs fall in this category
Class D: serious risk, use only if no other option
Class X: do not use in pregnant women in any circumstance
what often causes side effects of drugs?
interactions with off-target receptors
name the main categories of adverse drug reactions
hypersensitivity, non-receptor mediated, idiosyncratic, drug-drug
describe hypersensitivity reactions
theres 4 types: anaphylactic, cytolytic, arthus, and delayed hypersensitivity.
describe idiosyncratic reactions
patient-specific reactions, largely due to genetic polymorphisms of drug targets or enzymes/proteins impacting absorption
