Intro to Pharamacology Flashcards
study of substances that interact with living systems through chemical processes, especially by binding to regulatory molecules and activating or inhibiting normal body processes
Pharamacology
- what the BODY does to the DRUG
- great practical importance in the choice and administration of a particular drug for a particular patient e.g. renal function
Phamokinetics
Comes into play with choosing drug
- what the DRUG does to the BODY
- determines the group in which the drug is classified e.g. beta blockers
- Like mechanism of action
Pharmacodynamics
Drug to Body, determins class of drugs
What are the 4 elements of pharmacokinetics?
- Absorbtion
- Distribution
- Metabolism
- Excretion
ADME
Metabolims & Excretion are both elemination
Where do many orally administered medications pass through first after gut?
The liver then into plasma compartment
What part of the drug can enter the free tissues or site of action receptors?
Only the free drug can exit the plasama compartment
Injection of the drug into tissue
Intramuscular administration of drug
Injection of the drug straight into the blood; plasma
Intravenous
WHat are the 3 routes of drug administration?
- Oral
- Intramuscular injection
- Intravenous injection
Explain the time course of drug action
- Take drug, drug gets absorbed absorption phase
- Drug concentration increases to peak
- Drug gets distributed around body distribution
- Drug is excreted & metabolized elimination phase
What are the 4 diffrent ways drugs can cross memebranes?
- Aqueous diffusion
- Lipid Diffusion
- Special carries
- Endo/Exocytosis
What kind of drug permeation?
Drugs may diffuse passively through aqueous channels in the intercellular junctions (eg, tight junctions,
Aqueous Diffusion
What kind of drug permeation
lipid soluble drugs pass through lipid cell membrane
Lipid Diffusion
What kind of cell permeation?
Drugs with the appropriate characteristics may be transported by carriers into or out of cells
Special Carrier Diffusion
What kind of drug permeation
Very impermeant drugs may also bind to cell surface receptors (dark binding sites), be engulfed by the cell membrane ____ , and then released inside the cell or expelled via the membrane-limited vesicles out of the cell into the extracellular space____
Endocytosis & Exocytosis
What 5 thing does the rate and amount of absorbtion of a drug depend on?
- Local blood flow at site of admin (more flow= absorb better)
- Lipid Solubility (more lipid soluble easier to cross membrane)
- Molecular size (smaller passes esier throguh membrane)
- Local pH & Drug ionization (ionized drugs will not cross membrane)
- Total Surface Area of Absorbtion (More SA beter)
Where is the primary site of absorbtion for most oral drugs? why?
The small intestine
* It has vili that increase SA for absorbtion
fraction of unchanged drug reaching the systemic circulation following administration by any route
Bioavailability
Expressed in %
What is the bioavailibility of oral administered drugs? How about IV?
i.e How much will end up in systemic circulation
Oral= 75% bioavailable
IV= 100% always
metabolism of orally administered drug in the liver BEFORE it reaches the systemic circulation
First-Pass Effect
First-Pass Elemination
What is the result of a high first pass effect?
Decreased in bioavailibity
less reaches the systemic circulation
What Route of Admin?
PROS
* Conveinient
* Large surface area for absorbtion
CONS
* Drug metabolims
* Incomplete absorbtion
* First pass effect
* GI upset
Oral (PO)
What route of admin?
PROS
* Direct
* No First pass effect
* Slow infessions of rapid onset of action
* Esier to titrate does
CONS
* Req IV acess
* Hard to remove
* Vascular injury
Intravenous IV
What route of admin?
PROS
* To specific organs; brain & heart
CONS
Intra-arterial
What route of admin?
PROS
* Good for depot storage (if oil based)
* Rapi onset of action
CONS
* Pain at site of infection
Intra-muscular (IM)
What route of admin?
PROS
* Non irritating small volumes
* Even slow absorbtion
* Adrenaline in local anesthetics
CONS
* Paina at site of infection
Subcutaneous (SC)
What route of admin?
PROS
* Conventiant
* Localizied
* Limited systemic absorbtion
CONS
* Effects limited to area of application
Topical
What route of admin?
PROS
* Immediate action in lungs
* Rapid delivery to blood
* Local or systemic action
CONS
* Must be in gas, vapor, or aerosol form
Inhalation
What route of admin?
PROS
* Rapid onset of action
* No first pass effect
CONS
* Must be lipid soluble
Buccal
What route of admini?
PROS
* Direct application
* rapud onset of action
CONS
* Injection at site of application
* Delayed onset of action
Tansdermal
relates the amount of drug in the body to the concentration of drug (C) in blood or plasma
Volume of Distribution
What does a high volume of distribution signify?
Means that most of the drug concentration is enteing the extravascular tissue.
high amount of drug in the body
What affects Vd?
Affected by tissue and plasma binding and to which it binds more strongly too.
What does a low volume od distribution signify?
Most of the drug concentration is in the vascular compartment (blood)
If a drug is highly bound to plasma protien what is trend in VD
Low value of distributuion because it is stuck in the vascular compartment.
What are the ways in which drugs are bound?
- Free
- Bound to plasma protiens (albumin(
Why is it dangerous to administer two drugs are highly bound to plasma protein?
Discplacement of one or the other drug from plasma protiens can **result in toxicitiy. **
monitor pt. more