Pharmacokinetics Flashcards
What 4 properties determine how rapidly and how long the drug is administered to the target organ?
1) Absorption
2) Distribution
3) Metabolism
4) Excretion
What are the routes of administration determined by?
Properties of the drug and the therapeutic objectives of the drug
What are the 2 major routes of administration?
Enteral and Parenteral
When referring to routes of administration, what are 4 examples of therapeutic objectives?
Rapid Onset
Chronic Administration
Restriction to a local site
Setting in which it will be used
Describe Enteral Administration
Drug is administered by mouth.
Simplest form of administration
Drug is swallowed of placed under tongue
What is the simplest form of administration?
Enteral Administration
Advantages / Disadvantages of Oral Administration
Advantages:
- easily self administered
- Easier to overcome overdoses
- Large surface area for absorption
Disadvantages:
- Complicated pathway to absorption
- Harsh environment of stomach
- Metabolism of liver
Where is the major site of drug absorption and entry into systemic circulation for Oral Adminitration?
Small intestine
Most drugs absorbed in GI tract enter __________ ____________ prior to entering general circulation. What kind of metabolism is this?
Hepatic circulation
First Pass Metabolism
What are some advantages of Sub-Lingual Administration? (4)
Rapid absorption
Easily administered
Low incidence of infection
Avoid stomach and first pass metabolism
What are some advantages of Sub-Lingual Administration? (4)
Rapid absorption
Easily administered
Low incidence of infection
Avoid stomach and first pass metabolism
What is the preferred route of enteral administration for drugs that undergo extensive first-pass metabolism?
Sub-lingual Administration
Describe Parenteral drug administration. What is it used for? Some advantages and disadvantages and 3 major parenteral routes.
Parenteral administration is the introduction of drugs directly across the body’s barrier defenses (skin) into systemic circulation or other tissues. It bypasses the GI tract.
It is used for drugs that are poorly absorbed in GI tract and maybe too unstable for the GI. Also used to treat unconscious patients and when patient needs the drug quickly (rapid onset of drug).
Advantages:
Have the highest bioavailability
Not subject to first-pass metabolism
Provides the most control over the actual dose delivered
Disadvantages:
Irreversible
Can cause pain, fear, and/or infection
3 Major Parenteral Routes:
1) Intravascular (IV of IA)
2) Intramuscular (IM)
3) Subcutaneous (SC)
Describe intravenous parenteral administration
Most common parenteral route Rapid effects Not easily recalled Greater potential for toxic overdose Potential for infection Rate of infusion must be carefully controlled Similar concerns apply to IA drugs
Describe Intramuscular parenteral administration
Can be aqueous solutions (fast absorption) or depot preparations (slow absorption)
