Pharmacology - General Principles Flashcards
(42 cards)
What kinds of things do drugs target?
- Proteins on/in cells (g-proteins, ion channels, transmembrane receptors, intracellular receptors, or adhesion proteins)
- enzymes
- or can be free-floating chemical messengers
What is a type 1 dose-response relationship?
The graph represents the relationship between a dose and the number of receptors it binds to
With a type 1 dose-response curve, what does an antagonist chemical do to a curve/dose for an agonist drug?
It causes the curve to shift right, meaning the drug must be at a higher concentration to get the desired effect
With a type 1 dose-response curve, what happens to the agonist’s curve if there’s a noncompeting antagonist thrown into the mix?
The curve shortens, meaning the drug simply cannot bind to as many receptors
What is a type 2 dose-response relationship?
The graph represents the relationship between dose and the desired efficacy
How do you calculate therapeutic index (TI)?
Lethal dose 50/Effective dose 50
What is Emax on the dose-response curve?
It is the maximum number of receptors/efficacy that the drug can handle, regardless if the dose is raised
What does ADME stand for?
absorption, distribution, metabolism, excretion
How are drugs absorbed if taken orally?
Through the intestines and then the hepatic portal venous system
How are acids/bases distributed in the body?
weak bases tend to stay in the very acidic tissues, and weak acids tend to stay in the very basic tissues
What is an example of a distribution barrier in the body?
blood-brain barrier
Where are most drugs metabolized?
The liver, by cytochrome P-450 enzyme
Where are most drugs excreted?
The kidneys, by glomerular filtration, active tubular secretion, or passive tubular transfer
What are phase 1 metabolism techniques that the body uses?
oxidation, reduction, or hydrolysis
What are phase 2 metabolism techniques?
conjugation, meaning a chemical constituent is attached to the drug molecule
How do you calculate doseage?
Cp0 x Vd = initial plasma concentration, multiplied by volume of distribution
What does the curve look like for zero-order kinetics? First order?
Zero-order = linear line w/ negative slope First-order = concave line that slowly approaches x-axis
Do zero-order kinetic drugs or first-order have a greater risk for drug accumulation?
Zero-order
How can drug-drug interactions occur?
A drug could compete for receptors, or they can alter the metabolism of another drug
What is induction of drug metabolism?
It means a drug increases enzyme metabolism (usually P-450 in the liver) which speeds up the metabolism of another drug. Causes efficacy to drop.
What is inhibition of drug metabolism?
Means a drug competes for the enzyme or totally inhibits the enzyme’s action - this causes a drug to remain in the body longer and can be bad
How do genetic effect drugs?
A person’s enzyme profile determines the rate of metabolism/clearance of a drug
What is an idiosyncratic reaction?
an adverse reaction due to genetic changes usually involving a change in enzyme activity
What happens if you give diazepam/triazolam to a pt taking clarithromycin or itraconazole?
Increases sedation because the clarithromycin and itraconazole are metabolism inhibitors of CYP-450
