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NBDE pt. II - Pharmacology > General Principles > Flashcards

Flashcards in General Principles Deck (11)
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1

Define Absorption

The process of drug uptake from the site of administration and transfer into the blood stream

2

What dictates the rate and efficiency of absorption

Site of administration

3

Name which sites of administration have TOTAL absorption

Intravenous (IV)

4

Name which sites of administration have PARTIAL absorption

Oral
Intramuscular
Transmucosal/transdermal

5

Define Bioavailability

A measure of how much drug reaches the circulatory system and is available at the site of action

6

What 6 things affect the bioavailability of a drug

1. Route of administration
2. Degradation of drug prior to absorption
3. Gastrointestinal (GI) absorption mechanisms (active transport vs. passive diffusion)
4. Solubility (hydrophilic drugs vs hydrophobic drugs)
5. Hepatic first pass effect
6. Drug chemistry (presence of binders or dispersing agents, particle size, etc.)

7

Define Drug Distribution

The ability of a drug to move from the circulatory system into the interstitium and tissues

8

Factors affecting Drug Distribution

1. Blood flow
2. Protein binding
3. Permeability (ability to cross capillary barriers and specific types of capillary barriers that are largely impermeable such as the blood brain barrier)

9

Define Volume of Distribution (Vd)

A theoretical amount of fluid the drug is dispersed in after administration
Vd = total amount of drug in body/blood concentration of drug

10

Define a Phase I reaction of drug metabolism

Convert molecules into often still active slightly polar, water-soluble metabolites through oxidation, reduction, or hydrolysis reactions (e.g., cytochrome P-450 system)

11

Define a Phase II reaction of drug metabolism

Convert molecules into inactive polar metabolites via acetylation, glucouronidation, or sulfating that are then excreted by the kidneys