Reading...
Play button
Play button
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;
31 Cards in this Set
- Front
- Back
|
What is the measure of the bodies ability to eliminate the drug?
|
clearance
|
|
|
What is volume of distribution?
|
the measure of the apparent space in the body available to contain the drug
|
|
|
What is the equation for volume of distribution?
|
Vd= amount of drug in the body/C
|
|
|
What is the equation for clearance?
|
clearance=rate of elimination/C
|
|
|
What are the two major sites of drug elimination?
|
kidneys and liver
|
|
|
When a drug's clearance is first-order, how can it be estimated?
|
by calculating the area under the curve of the time-concentration profile after a dose
|
|
|
What type of elimination is dependent on the concentration of the drug that is achieved?
|
capacity-limited elimination
|
|
|
What is the rate of elimination equation for capacity-limited elimination?
|
(Vmax x C)/ (Km + C)
|
|
|
What three drugs is the capacity-limited elimination pattern important?
|
ethanol, phenytoin, and aspirin
|
|
|
What type of elimination is dependent on the rate of delivery to the organ of elimination?
|
flow-dependent elimination
|
|
|
What is a drugs half-life?
|
the time required to change the amount of drug in the body by one-half during elimination
|
|
|
What is the equation for half-life?
|
t1/2 = (.7 x Vd)/CL
|
|
|
What is the "rule of thumb" of half-life effects?
|
four half-lives must elapse after starting a drug-dosing regimen before full effects will be seen
|
|
|
If the dosing interval is shorter than ___ half-lives, the accumulation is detectable.
|
4
|
|
|
What is the equation for accumulation factor?
|
1/fraction lost in one dosing interval
|
|
|
What is the fraction of unchanged drug reaching the systemic circulation following administration by any route?
|
bioavailability
|
|
|
When does bioavailablility equal unity?
|
intravenous dose of the drug
|
|
|
What is the function of P-glycoprotein?
|
reverse transporter of drugs in the gut
|
|
|
What is the first-pass extraction ratio in the liver?
|
ER = CL/Q
|
|
|
What is the equation for systemic bioavailability of the drug?
|
F = f x (1-ER) f is the extent of absorption and ER si the extraction ratio
|
|
|
What determines the rate of absorption?
|
the site of administration and the drug formulation
|
|
|
When is the mechanism of drug absorption zero-order?
|
when the rate is independent of the amount of drug remaining in the gut
|
|
|
What is the equation for maintenance dose?
|
maintenance dose = dosing rate x dosing interval
|
|
|
What is the equation for the loading dose to match the peak steady-state concentration?
|
loading dose = maintenance dose x accumulation factor
|
|
|
What 2 factors determine the amount of drug that enters the body?
|
patient's compliance and rate/extent of transfer from the site of administration to the blood
|
|
|
What is drug sensitivity?
|
the concentration required to produce 50% of the maximum affect
|
|
|
What are the three factors that influence clearance?
|
dose, organ blood flow, and intrinsic function of the liver or kidneys
|
|
|
What drugs are exculsively bound to albumin?
|
phenytoin, salicyclates, and disopyramide
|
|
|
What drugs are exculsively bound to alpha1-acid glycoprotein?
|
quinidine, lidocaine, and propranolol
|
|
|
What increases alpha1-acid glycoprotein levels?
|
acute inflammatory disorders
|
|
|
What determines unbound drug concentrations?
|
dosing rate and clearance
|
