PHARMACOLOGY HNG 540 EXAM 1 STUDY GUIDE
Pharmacodynamics - Answers -what the drug does to the body
drug-receptor interaction and activity
dose response relationship
drug potency and efficacy
Pharmacokinetics - Answers -what the body does to the drug (absorption, distribution,
metabolism, excretion)
Drug-Receptor Interactions - Answers -Most drugs work by binding to receptors.
Receptors are located on the cell surface.
The drug molecule must "fit" into the receptor.
Like a lock and key mechanism
Drug-Receptor Binding - Answers -Drug-receptor binding is reversible.
Other substances can "un-bind" a drug, leaving more free drug to circulate
Drug-receptor binding is selective.
Drug-receptor binding is graded.
The more receptors filled, the greater the pharmacological response.
Drugs that bind to receptors may be agonists (enhances the activity of the cell), partial
agonists, or antagonistic (interferes with activity of the cell)
How Drug Dose Is Determined - Answers -Dose-response relationship
Therapeutic index
Plasma level profile
Half life
Bioavailability
drug dose relationship - Answers -Dose-response curve: depicts the relation between
drug dose and magnitude of effect
Doses below the curve do not produce a pharmacological response.
Doses above the curve do not produce much additional pharmacological response.
May have unwanted effects → toxicity
Drug bioavailability - Answers -Percentage of drug that is absorbed and available to
reach the target tissues
By definition, when a medication is administered IV, its bioavailability is 100%.
When a medication is administered via other routes (e.g., PO), its bioavailability
decreases due to incomplete absorption and first-pass metabolism.
first pass metabolism - Answers -Phenomenon in which the liver metabolizes some of a
drug before it can circulate through the body, particularly when the drug has been taken
orally.
, Half-life of a medication - Answers -the amount of time it takes for half of the drug to be
eliminated. Liver and kidney disease, aging, absence of food, and slowed metabolic rate
prolong half-life because of their effects on metabolism and excretion.
helps determine how often the medication is to be administered
steady state - Answers -The physiologic state in which the amount of drug removed via
elimination is equal to the amount of drug absorbed with each dose.
It usually takes 4 to 5 ½ half-lives [t ½ ] to get to steady state blood levels.
- Loading dose (for drugs with very long half lives)
It takes 4 to 5 ½ lives to totally eliminate a drug from the body.
drug absorption - Answers -movement of drug from site of administration into the blood
Variables that influence absorption:
- Nature of the cell membrane
- Blood flow at site of administration
- Solubility of drug
- pH
- Molecular weight
- Drug concentration
- Dosage form
drug distribution - Answers -passage of a drug from the blood to the tissues and organs
of the body
Distribution requires adequate blood supply.
Drug distributed to areas of high blood flow first
Areas of low blood flow
Example: in pt with pulmonary hypotension, the drug will be shunted away from lungs
protein binding drugs - Answers -allows part of the drug to be stored and part released
as needed. Drugs that are highly bound to plasma proteins or stored extensively in
other tissues have a long duration of action. Protein binding does not increase the
speed of action or increase metabolism. Protein binding does decrease the speed of
action by storing the drug to be released when needed.
Some of the drug is not bound and is called free drug.
Free drug + Bound drug ó Drug-protein complex
Dynamic
Free drug is active drug.
drug metabolism - Answers -the enzymatic biotransformation of a drug into metabolites
chemical change of drug structure to:
- enhance excretion
- Inactivate the drug
- Increase therapeutic action
- Activate a prodrug
- increase or decrease toxicity
Pharmacodynamics - Answers -what the drug does to the body
drug-receptor interaction and activity
dose response relationship
drug potency and efficacy
Pharmacokinetics - Answers -what the body does to the drug (absorption, distribution,
metabolism, excretion)
Drug-Receptor Interactions - Answers -Most drugs work by binding to receptors.
Receptors are located on the cell surface.
The drug molecule must "fit" into the receptor.
Like a lock and key mechanism
Drug-Receptor Binding - Answers -Drug-receptor binding is reversible.
Other substances can "un-bind" a drug, leaving more free drug to circulate
Drug-receptor binding is selective.
Drug-receptor binding is graded.
The more receptors filled, the greater the pharmacological response.
Drugs that bind to receptors may be agonists (enhances the activity of the cell), partial
agonists, or antagonistic (interferes with activity of the cell)
How Drug Dose Is Determined - Answers -Dose-response relationship
Therapeutic index
Plasma level profile
Half life
Bioavailability
drug dose relationship - Answers -Dose-response curve: depicts the relation between
drug dose and magnitude of effect
Doses below the curve do not produce a pharmacological response.
Doses above the curve do not produce much additional pharmacological response.
May have unwanted effects → toxicity
Drug bioavailability - Answers -Percentage of drug that is absorbed and available to
reach the target tissues
By definition, when a medication is administered IV, its bioavailability is 100%.
When a medication is administered via other routes (e.g., PO), its bioavailability
decreases due to incomplete absorption and first-pass metabolism.
first pass metabolism - Answers -Phenomenon in which the liver metabolizes some of a
drug before it can circulate through the body, particularly when the drug has been taken
orally.
, Half-life of a medication - Answers -the amount of time it takes for half of the drug to be
eliminated. Liver and kidney disease, aging, absence of food, and slowed metabolic rate
prolong half-life because of their effects on metabolism and excretion.
helps determine how often the medication is to be administered
steady state - Answers -The physiologic state in which the amount of drug removed via
elimination is equal to the amount of drug absorbed with each dose.
It usually takes 4 to 5 ½ half-lives [t ½ ] to get to steady state blood levels.
- Loading dose (for drugs with very long half lives)
It takes 4 to 5 ½ lives to totally eliminate a drug from the body.
drug absorption - Answers -movement of drug from site of administration into the blood
Variables that influence absorption:
- Nature of the cell membrane
- Blood flow at site of administration
- Solubility of drug
- pH
- Molecular weight
- Drug concentration
- Dosage form
drug distribution - Answers -passage of a drug from the blood to the tissues and organs
of the body
Distribution requires adequate blood supply.
Drug distributed to areas of high blood flow first
Areas of low blood flow
Example: in pt with pulmonary hypotension, the drug will be shunted away from lungs
protein binding drugs - Answers -allows part of the drug to be stored and part released
as needed. Drugs that are highly bound to plasma proteins or stored extensively in
other tissues have a long duration of action. Protein binding does not increase the
speed of action or increase metabolism. Protein binding does decrease the speed of
action by storing the drug to be released when needed.
Some of the drug is not bound and is called free drug.
Free drug + Bound drug ó Drug-protein complex
Dynamic
Free drug is active drug.
drug metabolism - Answers -the enzymatic biotransformation of a drug into metabolites
chemical change of drug structure to:
- enhance excretion
- Inactivate the drug
- Increase therapeutic action
- Activate a prodrug
- increase or decrease toxicity
