Exam 1 Practice Questions Flashcards
What is the largest barrier to intestinal absorption?
permeability
What are some factors to intestinal permability?
- Solubility (Equilibrium of acid or base
with water) - Metabolism
- Transporters vs diffusion
- Transit time (Species differences)
toxicokinetics
define distribution
The reversible transfer of drug from one location to another in the body.
Generally, this is thought of as the movement of a drug out of the blood and into tissues.
Slide 26 on toxicokinetics lecture
True or False:
Active transport can be found in all tissues and plays a role in uptake, exclusion, and excretion
True
Describe first order vs zero order kinetics of drug metabolism
First order kinetics occur when a constant fraction of the drug is eliminated per unit time. The rate of drug elimination is proprtional to drug plasma concetration.
Zero order: a constant amount of drug is eliminated per unit time. The rate of drug elimination is independent of drug plasma concetration.
slide 28 on toxicokinetics lecture
What is the role of phase II metabolism?
Phase II metabolism, addition of glucoronic acid/glutathione/glycine etc., is intended to make xenobiotics less likely to be reabsorbed.
How could you enhance elimination of
a xenobiotic that is a weak acid?
A formal charge on the drug leads to increased urinary elimination due to decreased reabsorbtion from the proximal tubule
What a the three classes of antidotes?
Chemical or causal antidotes
* Works directly on the toxicant through binding to generate an
inactivated product that can be excreted from the body.
Functional antidotes
* Does not physically interact with the toxicant but works to
lessen the clinical signs associated with intoxication
Pharmacological or physiological antidotes
* Works in the opposite manner as the toxicant at a receptor
(agonistic vs. antagonistic)
* Prevent formation of a toxic metabolite
* Facilitate a more rapid elimination of the toxicant
* Aid in restoration of normal body function
