1.1 Flashcards
What is PK? Acronym?
how the body works on the medication:
ADME- absorption, distribution, metabolism, and elimination
What is PD?
how the drug is acting upon the body
What are the enteral routes?
Oral, SL, Buccal, Feeding tube
What are the Topical routes?
PR, transdermal, creams
What are the parenteral routes?
IV, IM, SC
What are the 2 modes of absorption?
Paracellular
Transcellular
What is paracellular absorption?
drug or active ingredient is absorbed between cells, goes between the gap between cells, drug in ECF
What is transcellular absorption?
rug must cross through cell, passive, active txp, or endocytosis
What is Vd? What is the formula?
How much volume is the drug being distributed into.
Vd = (Amount of drug in body)/ (conc. Of drug in blood or plasma)
What does it mean for a drug to have high Vd? Examples?
much higher conc. in Extravascular tissue or drug extensively distribute into body tissues and fluids
i.e. Digoxin, diltiazem, imipramine, labetalol, metoprolol, meperidine, and nortriptyline
high Vd, then the drug is dissipated through body more effectively (think about the math…) may take longer to eliminate, the drug stays mostly in extravascular tissue (outside of bloodstream, eg bone, fat, liver)
What does it mean for a drug to have a low Vd?
Drugs have low Vd – retained mostly within the vasculature (Intravascular) or limited drug distribution
i.e. aminoglycosides
What is the AUC? Why is this useful?
area under the curve-AUC, which tells us how much drug exposure a pt has had in a given timeframe. ALSO, allows us to predict behavior of the drug, eg the level of the drug, without lab draw, and titrate to a therapeutic effect.
In a 2 compartment model, what are the 2 compartments?
Central- Heart, liver, lungs, kidneys, blood
Peripheral- Fat, muscle, CSF
What is the MEC?
Minimum effective concentration
What is the first pass loss? How is this corrected for?
First pass loss (i.e. First pass effect): The loss of a drug before getting to site of action when it first pass through the GI and liver.
Drugs that have extensive first pass loss require much larger oral than IV doses to achieve the same effects
What are the 4 common biochemical ways drugs are metabolized?
Oxidation
Reduction
Hydrolysis
Conjugation
What three types of conjugation occur in drug metabolism?
“GAS”
Glucuronidation: Adding glucuronic acid to the molecule
Acetylation: Adding an acetyl group to another molecule
Sulfation: Adding a sulfate to another molecule
What happens in phase 1 of drug metabolism?
Oxidation, Reduction, and Hydrolysis
Generally result in loss of pharmacological activity
What happens in phase 2 of drug metabolism?
Conjugation
Covalent link functional group with endogenous glucuronic acid, sulfate, glutathione, AA, or acetate
What is a prodrug?
inactive compounds designed to max the amount of active species at site of action
Metabolized into active form
How are prodrugs activated?
hydrolysis of an ester or amide linkage
What do acidic drugs bind to?
albumin
What do basic drugs bind to?
Alpa-acid glycoprotein
What do thyroid hormone, estrogen, and tester one bind to?
Thyroid- thyroxin binding globulin
Estrogen- sex-binding globulin
Testosterone- sex-binding globulin
When is protein binding clinically relevant?
high clearance with narrow therapeutic index drugs
= adding a little can up the amount in the blood a lot!
