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;
16 Cards in this Set
- Front
- Back
|
What is clearance?
|
The vol of blood that must be acted on per unit of time by the organ to acct for the rate of elimin by the organ. Describes the efficiency of drug removal from the eliminating organ. (ml/min)
|
|
|
What is total body clearance (TBC) or systemic clearance (Cls)?
|
The sum of all clearance processes in the body. Calc easily by model independent methods. Cls=TBC=Clrenal+Clhepatic+Clother or iv dose/AUCo
|
|
|
How can renal clearance (Clr) be calc?
|
fraction of dose excreted unchanged in urine * Cls
|
|
|
How many t1/2 does it take for elimination to be close to 100%?
|
4-7 half lifes. 4 t1/2=94% complete & 7 t1/2= 99.2%
|
|
|
How is t1/2 calc?
|
0.7*Vd/Cls
|
|
|
What factors affect total body clearance?
|
Enzyme induction, disease states, drug protein binding, changes in blood flow to organ, physiological variables
|
|
|
What is an example of how enzyme induction can affect Cls?
|
Co-admin of phenobarbital will lead to inc meta of many drugs. Phenobarbital is an inducer
|
|
|
What is an example of how disease states affect Cls?
|
Cirrhosis or renal failure may dec Cls due to organ insufficiency
|
|
|
What is an example of how drug protein binding can affect Cls?
|
Decreased phenytonin plasma protein binding during uremia due to dec plasma albumin concen & displacement by endogenous substances
|
|
|
What is an example of how changes organ blood flow can affect Cls?
|
Lidocaine can inc meta clearance in patients in congestive heart failure. In CO->inc liver blood flow
|
|
|
What is an example of how physiological variables affect Cls?
|
Renal excretion can be altered if urine pH cahnges due to diet
|
|
|
What is common to all non-vascular routes of admin?
|
An absorption step
|
|
|
What is the primary route of drug admin?
|
oral (b/c of convenience)
|
|
|
What are some reasons for problems w/ absorption efficiency?
|
Poor performance of dosage form; Patient variables & manufacturing variables
|
|
|
What is an important factor in absorption?
|
bioavailability- the quantitation & extent of absorption
|
|
|
How is absolute bioavailablity calc?
|
% bioavail=F*100%= (AUCo)po *dosepo/ (AUC)iv*doseiv
|
