PHARM: Drug Absorption, Distribution, and Excretion Flashcards Preview

1 Foundations of Disease and Therapy > PHARM: Drug Absorption, Distribution, and Excretion > Flashcards

Flashcards in PHARM: Drug Absorption, Distribution, and Excretion Deck (21):
1

What is drug distribution?

The process of binding of a drug to a plasma protein, a tissue compartment, or a receptor site

2

What is the order (from fastest to slowest) that barbitol, thiopental, hexobarbital, and phenobarbital are metabolized?

Thiopental, barbital, hexobarbital, phenobarbital

3

What is the partitioning coefficient (Kp)?

[drug]lip/[drug]aq

4

What is the effect of oxygen, sulfur, and nitrogen on the partitioning coefficient?

Decreases (makes more hydrophilic)

5

True or False: Drugs with a higher partitioning coefficient would pass more slowly through a cell membrane.

False

6

What does pK represent with regards to drug ionization?

pK is the pH at which a drug will be 50% ionized and 50% non ionized

7

True or False: If a drug is ionized in a particular biologic fluid, it has a tendency to stay there and accumulate

True

8

What is filtration? What limits distribution in this fashion?

Transfer through pores/ fenestrations in capillaries; molecular weight/ size

9

What mechanisms of drug transport are saturable?

Active transport, facilitated diffusion, receptor-mediated endocytosis

10

What are the two major routes of drug administration?

Enteral (through the GI) or Parenteral (outside the GI tract)

11

What are the routes of parenteral drug administration?

Intravenous, intramuscular, subcutaneous, inhalational, transdermal

12

What are the advantages and disadvantages of IV drug administration?

Advantages- no absorption; attain desired drug concentration more rapidly, can adjust dosage more readily, can administer irritating solutions, bypasses first-pass effect; Disadvantages- risk of infection, pain/difficult self-admin., no drugs that precipitate in blood or oily vehicles

13

What is the first-pass effect?

The SI and liver contain a lot of the metabolic enzymes that degrade drugs and so enteral administration causes the drug to be exposed to those enzymes before systemic circulation

14

What is the mechanism by which a drug administered intramuscularly is absorbed?

Filtration

15

How can the absorption rate of a drug delivered IM be altered?

Changing muscle to muscle with different flow or by changing the drug vehicle

16

What method of parenteral drug admin provides slow and constant absorption

Subcutaneous

17

True or False: inhalational administration can be for both systemic and local effects?

True

18

What are the disadvantages of inhalational drug administration?

Cumbersome administration and difficulty in dosage regulation

19

What is the transport mechansim by which drugs are absorbed transdermally?

Passive diffusion

20

What are the disadvantages of enteral administration?

Gastric irritation, destruction of drugs in GI, irregular absorption, patient cooperation, first-pass effect

21

What is the primary site of drug absorption?

Small intestine