Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
35 Cards in this Set
- Front
- Back
|
What is Pharmacokinetics (PK)? |
what the human body does to a drug |
|
|
What is Pharmacodynamics (PD)? |
what the drug does to the human body |
|
|
PK involves |
absorption, distribution, metabolism and excretion |
|
|
PK is used to.. (2) |
1. assess drug levels 2. optimize drug therapy |
|
|
PD refers to |
the relationship between the drug concentration at the site of action and both therapeutic and adverse effects |
|
|
Absorption of oral drugs occurs via 2 primary processes |
1. passive diffusion 2. active transport |
|
|
If the drug has a poor absorption, one of the methods used to increase the dissolution rate is to.. |
reduce particle diameter, which increases surface area (micronized) |
|
|
Drugs with poor absorption that are micronized include.. (2) |
progesterone and fenofibrate |
|
|
Which equation described the rate of dissolution? |
Noyes-Whitney equation |
|
|
What is bioavailability? |
% of drug absorbed from the extravascular administration (PO) relative to intravascular administration (IV) |
|
|
Levofloxacin has what kind of bioavailability? |
high; PO and IV doses are the same |
|
|
Biphosphonates have what kind of bioavailability? |
low oral bioavailability IV: 3mg q 3 mo PO: 150mg PO q month |
|
|
Absolute bioavailability (F) equation |
F (%) = 100 x (AUC extravascular/AUC iv) x ( DOSE iv / DOSE extravascular) |
|
|
Factors that favor passage across membranes and greater drug distribution to the tissues include |
1. high lipophilicity 2. low molecular weight 3. unionized status 4. low protein binding |
|
|
Primary protein responsible for drug binding |
albumin |
|
|
What form of the drug is able to interact with receptors and exert therapeutic or toxic effects |
unbound (free) form |
|
|
Higher % of drug would be in unbound form if it is.. |
highly protein bound (>90%) and low serum albumin (<3.5 g/dL) |
|
|
Volume of distribution (Vd) equation |
Vd = Amount of drug in the body / Concentration of drug in plasma |
|
|
Phase I rxns include |
oxidation, reduction and hydrolysis |
|
|
Phase II rxn include |
conjugation reactions (ex: glucoronidation) |
|
|
What are first-pass metabolism reactions? |
1. the process of partially or extensively metabolized by the liver before they reach the systemic circulation 2. the bioavailability of the drug is the reduced |
|
|
Clearance (Cl) equation |
Cl = Rate of elimination / Concentration Cl = Dose/AUC Cl = (F x Dose) / AUC |
|
|
Zero-order elimination |
a constant amount of drug is removed per unit of time |
|
|
First-order elimination |
a constant % of drug is removed per unit of time |
|
|
Michaelis-Menten kinetics (saturable kinetics) |
1) begins as first-order kinetics but at higher concentrations the rate of metabolism approaches maximum capacity 2) any increase in dose leads to a disproportionate increase in drug concentration at steady state |
|
|
At concentrations less than Km, the rate of metabolism becomes |
first order |
|
|
At concentrations above the Km, the rate of metabolism becomes |
mixed (first and zero order) |
|
|
At high concentrations relative to Km the rate of metabolism becomes |
zero order |
|
|
Which medications have saturable kinetics? |
Phenytoin, Theophylline and Voriconazole |
|
|
How to dose adjust phenytoin? |
in small increments (30-50mg) when the serum concentration is >7mg/L |
|
|
Elimination rate constant (ke) is.. |
the fraction of the drug that is eliminated per unit of time |
|
|
ke equation |
ke = Cl / Vd |
|
|
What is half-life? |
the time required for the drug concentration to decrease by 50% |
|
|
half life equation (t 1/2) |
t1/2 = 0.693 / ke |
|
|
Loading dose concentration |
LD = (Desired concentration x Vd) / F |
