Pharmacology

Question 1

Enteral administration means drugs that enter via the […] tract

Answer 1

Alimentary (digestive, given orally)

Systemic effect

Question 2

What does parenteral mean?

Answer 2

Routes of administration that bypass the gut (IV)

Usually more rapid onset than other routes

Systemic effect

Not subject to first pass metabolism

Highest bioavailability

Question 3

Answer 3

Question 4

A drug applied to the skin can diffuse from the […] through the epidermis and then the dermis to enter […].

Answer 4

Stratum corneum

Capillary microcirculation and thus the systemic bloodstream

Question 5

Drugs that are small struggle with […]

Answer 5

Receptor specificity

Question 6

Drugs that are large struggle with […]

Answer 6

Diffusing through lipid membranes

Question 7

• What is the principle barrier to penetration of drugs through the skin?
• What 2 factors influence a drugs ability to pass through the skin into circulation?

Answer 7

Question 8

When is cutaneous (topical) administration used?

Answer 8

When a local effect on the skin is required. However, appreciable absorption may occur and lead to systemic effects so these medications must not be taken lightly.

Question 9

Transdermal

• What is this route of administration?
• What is its absorption pattern?
• What are the advantages?
• What are the disadvantages?

Answer 9

Question 10

Subcutaneous administration

• What is it?
• What is its absorption pattern?
• What are the advantages?
• What are the disadvantages?

Answer 10

Question 11

[…] drugs are presented in vehicles, designed to vary in the extent to which they increase hydration of the stratum corneum.

Answer 11

Dermal

Question 12

Dermal drugs increase the hydration of the stratum corneum as part of their mechanism of action. Why does increasing the hydration affect drug administration?

Answer 12

Becuase increasing the water content of the stratum corneum via occlusion or hydration generally increases the penetration of both lipophilic and hydrophilic materials (i.e. drugs). Hydration makes the stratum corneum and stratum granulosum more similar, so molecules are able to penetrate more easily.

Question 13

Some vehicles also contain substances such as fatty acids, tarpenes and surfactants. What is the role of these molecules in drug delivery?

Answer 13

To enhance penetration by reducing barrier properties of the stratum corneum

Question 14

What effect does encapsulating drugs into vesicular liposomes have on drug delivery?

Answer 14

Enhances drug delivery to specific compartments of the skin (i.e. hair follicles)

Question 15

What affect do occlusive dressings (impermeable plastic membranes) have on drug absorption?

Answer 15

Increases as much as 10-fold

Question 16

Rank the locations of skin on the body from highest absorption to lowest absorption.

Answer 16

Question 17

What effect does skin damage (inflammation, burn, exfoliation) have on absorption?

Answer 17

Increases absorption due to decrease in barrier function

Question 18

How are dermal drugs excreted?

Answer 18

Excretion of drugs into sweat occurs but has only minor importance. For most drugs, excretion mainly depends on the diffusion of the un-ionized lipid soluble form of the drug across the epithelial cells of the sweat glands. Although drugs do appear in sweat, it is unclear if active drug transport occurs across the ducts of the sweat glands. The small amount that does appear in sweat may be somewhat responsible for dermatitis or other skin reactions.

Question 19

Intramuscular delivery

• Absorption pattern
• Advantages
• Disadvantages

Answer 19

• Aqueous solution (absorbed rapidly) or specialized depot (absorbed slowly)
• Suitable if drug volume is moderate, suitable only for oil vehicles and certain irritating substances; preferable to IV if patient must self administer
• Affects certain lab tests (creatine kinase); can be painful; can cause intramuscular hemorrhage

Question 20

Oral administration is:

a) topical
b) parenteral
c) enteral

Answer 20

C

Question 21

Intravenous administration is:

a) topical
b) parenteral
c) enteral

Answer 21

B

Question 22

Intramuscular administration is:

a) topical
b) parenteral
c) enteral

Answer 22

B

Question 23

Subcutaneous administration is:

a) topical
b) parenteral
c) enteral

Answer 23

B

Question 24

Cutaneous administration is:

a) topical
b) parenteral
c) enteral

Answer 24

A

Question 25

Transdermal administration is:

a) topical
b) parenteral
c) enteral

Answer 25

A