W4-2 Pharmacodynamics Flashcards
Agonist
Activates biochemical events, “evokes response”
Most common second messenger system
G-protein coupled receptors
Best known pharmacologic interaction mechanism
Ligand-gated ion channels
Pharmaceuticals often bind ________ proteins in order to ________ transcription
chaperone, inactivate
Major reason for drug-drug interactions
Overlapping 2nd messenger systems
Two types of drugs that do not interact with receptors
Chelating agents
Volatile anesthetics
Antimetabolites
Interfere with DNA/RNA synthesis
What is EC50?
The amount of drug needed to elicit 50% of the maximal response
Affinity
1/Kd (1/dissociation constant)
Potency
Compares relative drug strengths
Antagonist
Inhibits action of agonist, efficacy alpha = 0
Quantal Dose Effect
Population response, “all or nothing” response over very narrow concentration range
Tachyphylaxis
Hyporeactivity induced rapidly after a few doses
Therapeutic index
TI=LD50/ED50
Higher is better
Cyt P-450 types for codeine metabolism
More 2D6 than 3A4
Quinidine reduces 2D6
Grapefruit juice reduces 3A4
3 benefits of personalized medicine
- Safer drugs
- Increased effectiveness
- Dosages calculated on genetics
2 alleles that can be examined before starting warfarin therapy
VKORC1 (vitamin K epoxide reductase)
CYP2C9 (cytochrome p450 2C9)
Molecular test that may be used for detecting SNPs
Deep sequencing
Exon trapping
Direct sequencing
Describe general role of cytochrome p450 gene family
Drug metabolism, activation and breakdown
3 general types of metabolizers and the significance for pain management
“Poor metabolizers” cannot metabolize codeine
“Extensive metabolizers” can metabolize codeine
“Ultrarapid metabolizers” metabolize codeine too quickly
When is a genetic test needed prior to administering cancer therapy?
When we look for specific biomarkers to attack
Golden equation of flow
delta P
flow= ————
R
Gut associate lymphoid tissue
trained by normal intestinal flora to respond appropriately to invaders
