Pharmacology Flashcards
Enteral administration means drugs that enter via the […] tract
Alimentary (digestive, given orally)
Systemic effect
What does parenteral mean?
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
A drug applied to the skin can diffuse from the […] through the epidermis and then the dermis to enter […].
Stratum corneum
Capillary microcirculation and thus the systemic bloodstream
Drugs that are small struggle with […]
Receptor specificity
Drugs that are large struggle with […]
Diffusing through lipid membranes
- 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?
When is cutaneous (topical) administration used?
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.
Transdermal
- What is this route of administration?
- What is its absorption pattern?
- What are the advantages?
- What are the disadvantages?
Subcutaneous administration
- What is it?
- What is its absorption pattern?
- What are the advantages?
- What are the disadvantages?
[…] drugs are presented in vehicles, designed to vary in the extent to which they increase hydration of the stratum corneum.
Dermal
Dermal drugs increase the hydration of the stratum corneum as part of their mechanism of action. Why does increasing the hydration affect drug administration?
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.
Some vehicles also contain substances such as fatty acids, tarpenes and surfactants. What is the role of these molecules in drug delivery?
To enhance penetration by reducing barrier properties of the stratum corneum
What effect does encapsulating drugs into vesicular liposomes have on drug delivery?
Enhances drug delivery to specific compartments of the skin (i.e. hair follicles)
What affect do occlusive dressings (impermeable plastic membranes) have on drug absorption?
Increases as much as 10-fold
Rank the locations of skin on the body from highest absorption to lowest absorption.
What effect does skin damage (inflammation, burn, exfoliation) have on absorption?
Increases absorption due to decrease in barrier function
How are dermal drugs excreted?
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.
Intramuscular delivery
- Absorption pattern
- Advantages
- Disadvantages
- 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
Oral administration is:
a) topical
b) parenteral
c) enteral
C
Intravenous administration is:
a) topical
b) parenteral
c) enteral
B
Intramuscular administration is:
a) topical
b) parenteral
c) enteral
B
Subcutaneous administration is:
a) topical
b) parenteral
c) enteral
B
Cutaneous administration is:
a) topical
b) parenteral
c) enteral
A
Transdermal administration is:
a) topical
b) parenteral
c) enteral
A
