Pathophysiology and Drug Action Exam 2 (Set 4)

Question 1

What are the key means by which drug effect is quantified and compared? (onset, intensity and duration)

Answer 1

-Time-Action curves
Onset: where the duration of time begins
Intensity: how long the drug effect will reach (peak effect)
Duration: how long this will occur

Question 2

What are the differences between a quantal and graded drug response?

Answer 2

quantal: is all-or-none dose-response relationships
-has an MEC that evokes this all-or-none response
-normal frequency distribution
Graded: not all-or-none, progressively increasing effects with increasing concentrations
-S-shaped sigmoidal curve (both)

Question 3

calculate and compare the therapeutic index between drugs

Answer 3

quantal: LD50/ED50 or TD50/ED50
-larger the ratio the greater the safety

Question 4

Which is NOT a graded response?
A) blood sugar lowering effect of insulin
B) blood pressure control by propanolol
C) Prevention of anaphylaxis to penicillin by norepinpehrine
D) Dilation of eye pupils by atropine

Answer 4

C) prevention of anaphylaxis to penicillin by norepinephrine

Question 5

Describe the factors that modify the effects of drugs

Answer 5

-Drug tolerance
1. drug disposition/metabolic tolerance (decrease in effective concentration at the site of action)
2. cellular or pharmacologic tolerance (decrease in the normal reactivity of the receptor)

Question 6

What is cross tolerance?

Answer 6

-tolerance develops to one drug that is also seen with drugs belonging to the same class; not always complete
-basis for opioid rotation

Question 7

What is tachyphylaxis?

Answer 7

acute development of tolerance following rapid and/or repeated administration of a drug

Question 8

what are some factors that modify the effect of drugs?

Answer 8

-Physiological variables (age, gender, pregnancy, food, circadian clock)
-Pathological factors (liver disease, renal disease, malnutrition)
-Genetic factors (Pseudocholinesterase deficiency, Malignant hyperthermia, oxidation polymorphism)
-Interaction with other drugs (Pharmacokinetic, Pharmacodynamic)

Question 9

What is the basis for on-target and off-target adverse effects?

Answer 9

“On-target” drug reaches intended receptor
-experience “on-target” adverse effects
“Off-target” drug does not reach intended receptor; binds to unintended receptor
-experience “off-target” adverse effects