Pharmacokinetics Flashcards
List the routes of administration of a drug
1) absorption
2) distribution
3) metabolism (biotransformation)
4) elimination
(ADME)
The movement of a drug from the site of administration into the blood
Absorption
Term that describes how once in the blood, the drug moves to various parts of the body
Distribution
Term used for when the drug is converted to a form that is more readily eliminated
Metabolism (biotransformation)
Metabolism or excretion of the drug from the body
Elimination
When does the drug move from pharmacokinetics to pharmacodynamics
When the drug reaches it’s site of action and when it starts showing an effect because it starts binding to receptors
What route of administration is convenient, but slower and less complete than parenteral (around the GI tract) forms?
Oral
What are ingested drugs subject to?
First-pass effect (portal circulation)
What is the first-pass effect?
Blood from the GI tract passes through the liver before entering other organs; during the first pass through the liver, some or nearly all of a drug can be metabolized to an inactive or less active derivative; as a result, some drugs are useless when given orally
What does it mean for a drug to be parenteral?
Around the GI tract (ex: IV)
What is the difference between oral administration and IV administration when it comes to over-dosing?
Oral: have time to combat it b/c it has to make it through the system first
IV: don’t have time to combat it
What part of the body is the major site of absorption following oral administration? Why?
Intestines because they have a lot of surface area
What route of administration means in the pouch between the cheek and gums, and permits direct absorption into the systemic venous circulation (can be fast or slow)
Buccal
What route of administration is under the tongue and permits direct absorption into the systemic venous circulation?
Sublingual
What is an example of a sublingual route of administration?
Nitroglycerin for angina
What route of administration is good for a patient who is nauseous or vomiting, and is formulated as a suppository?
Rectal
What route of administration is often faster with absorption and more complete than with oral, and can be given in large volume?
Intramuscular
What are the compartments in intramuscular absorption?
Compartment 1 = muscle
Compartment 2 = blood
What route of administration offers slower absorption than the intramuscular route due to more vasculature, but large volume doses are feasible
Subcutaneous
What is an example of subcutaneous administration?
Insulin
What route of administration does not involve absorption (bioavailability is 100% = measures how much of your dose got into the blood), and can be dangerous b/c of the high blood levels that are produced if administration is too rapid
Intravenous (IV)
How many compartments are involved with IV?
1 = blood
What route of administration offers delivery closest to the target tissue, providing the most rapid absorption because of the large surface area available?
Inhalation (due to the alveoli)
What route of administration includes any application to the skin or the mucous membranes of the eye, nose, throat, airway, or vagina for LOCAL effect; the rate of absorption is usually slower than any of the other routes
Topical
Where is one place that we never want topical administration to reach?
The blood
What is an example that you would need topical administration for?
Rash
What route of administration involves application to the skin for SYSTEMIC effects; absorption usually occurs very slowly, but the first-pass effect is avoided (absorption is ALWAYS involved); drug must be potent
Transdermal
Example of transdermal administration
Nicotinic patch
What are the 3 types of administration that are parenteral (around the GI tract)?
IV (intravenous)
IM (intramuscular)
SC (subcutaneous)
Can a system that doesn’t use a carrier be saturated?
Nope
Most common type of drug movement in the body?
Passive diffusion
Drug movement in the body that is driven by concentration gradient across a membrane;
No carrier
Not saturable
Low structural specificity
Passive diffusion
Drug movement in the body that is driven by concentration gradient
Involves specific carrier proteins
Is saturable
No energy is required
Facilitated diffusion
Drug movement in the body that moves against a concentration gradient
Involves specific carrier proteins
Is saturable
Needs ATP
Active transport
What are the 2 things you have to decide on in order to figure out the drug movement in the body
1) Does it need a carrier? (saturable or not?)
2) Did it need energy?
Given the example:
Give certain amount of drug and that drug moves into the cells. Then give more of that drug and more of it moves into the cells. Then give even more and even more moves into cells. If every time I give more drugs and more movement occurs, this shows what?
The drug is not saturated, which means that it is using passive diffusion
Given the example:
You used a drug to inhibit ATP. If you stop ATP production, and the drug stops moving, then what type of movement is the drug using?
Active transport
Given the example:
You used a drug to inhibit ATP. If you stop ATP production, and the drug continues to move, then what type of movement is the drug using?
Facilitated diffusion