Lec. 2 - Pharmacodynamics 1 Flashcards
What are the 3 ways drugs can be named?
- Chemical name: useful for chemical formula + structure
- Generic name: universal name adopted by USAN and WHO
- Trade name: Registered trademark
What’s the difference between pharmacodynamics and pharmacokinetics?
Pharmacodynamics: what the drug does to the body
Pharmacokinetics: what the body does to the drugs
What are indications?
And contraindications?
Indications: when/how to use drug
Contraindications: when/how NOT to use drug
What are the 4 principles of pharmacokinetics?
- Absorption
- Distribution
- Metabolism
- Excretion
ADME!
What are the 4 mechanisms through which a drug can affect a system?
Through…
- Receptors
- Ion channels
- Enzymes
- Immune system
What are 6 principle methods of drug administration?
Sublingual Parenteral Inhalation Topical Oral Rectal
(SPIT, OR [else])
What are 4 features of oral administration of drugs?
- easy/cheap/convenient
- generally uses modified-release tablets
- Most absorption in small intestine (some in stomach)
- Significant amount of drug is inactivated by the liver during first pass
Describe how the liver affects drug absorption upon administration.
First pass effect:
Upon absorption into the blood stream, the drug passes into the liver, which inactivates a significant portion of the drug.
Proportion of what’s left (compared to administration) is called bioavailability.
Describe 3 features of parenteral drug administration
- Injection
- Fast, accurate, bypasses liver
- 3 injection sites (from superficial to deepest):
1. Subcutaneous
2. Intravenously
3. Intramuscularly
Describe inhalation as drug administration.
-lungs have large surface area, so there is a greater amount of distribution
- Systemic effects occur in seconds
(ex. Cigarette in 7 seconds reached brain)
-Nasal mucosa effects in minutes
(Ex. Cocaine)
Describe 2 features of topical drug administration.
- skin is made to prevent absorption, so more difficult
- still some methods of workaround (ex. The patch)
Describe 3 features of sublingual drug administration
- under the tongue
- straight into vasculature, avoids first pass of liver
- very rapid effects
How do drugs effect an organism (micro to macro)
Targets…
Subcellular structure (ex. Receptors) -> Cell -> Tissues -> Organs/organ systems
What is drug selectivity?
What is the drug target? How localized will the effect be?
What are some drugs that have little to no specificity (name 4)
- Osmotic agents
- Acidifying drugs
- Alkylinizing drugs
- metal chelators
Basically, simple chemical agents that diffuse around
What is a drug receptor?
How do they mediate drug activity?
A macro molecular protein (generally membrane bound) to which endogenous ligand or exogenous agonist/antagonist will bind.
Link to cellular response machinery allows for downstream effect
Name methods of transmembrane signalling mechanisms
I. Intracellular receptor
II. R-activated enzyme
III. R-activated tyrosine kinase
IV. R-Activated ion channel
V. G protein coupled receptor
Describe ion channels (4)
- Transmembrane protein
- Very specific in which ion it allows passage (selectivity pire)
-3 states:
I. Open
II. Closed
III. Inactivated
-Voltage/binding/pressure controlled
What are carrier molecules? What is there function in cells?
Transport proteins that help regulate and maintain electrochemical gradient.
What are GPCRs (3)
-7 transmembrane domains
-g-protein activation will activate or inhibit an enzyme, which produces a second messenger that either
•Opens/closes ion channel
•Has other cellular downstream effects
-frequent target of hormones
What is receptor turnover?
After use, a receptor can be recycled, degraded or more
How does receptor Tyrosine kinase work?
Dimerization!
- Ligand binds first receptor
- Second receptor diner is es
- Activates TKR proteins (through phosphorylation)
- Causes downstream effects, such as transcription
Describe cytokines receptor activity
Similar to TKRs, dimerize to activate, intracellular proteins are phosphorylation, then relocate to nucleus and activate transcription
What are naturetic peptide receptors?
Receptors that respond to peptides (less common)
Describe 4 features of intracellular receptors
- Found within cells (not on membrane)
- Hormones must diffuse to activate (ie ligands must be lipophilic)
- Function - alter gene transcription/protein synthesis
-3 main types
I. Estrogen
II. Progesterone
III. Glucocorticoid
What is the timescale of response for
- Ion channels
- GPCRs
- Enzymes
- DNA-linked receptors
- Msec
- Sec
- Min
- Hours
Are there drugs that bypass receptor activity? Ex.?
Yes, some interrupt/stabilize actual cell processes,
ex. Drugs that interrupt microtubule formation (disrupting mitosis)
