Excretion Flashcards
Cl = ?
clearance
Definition of Renal Clearance (Clr)
the volume of plasma that is freed of the substance (drug) per unit of time
Clr doesn’t mean anything by itself, need to put it into context with ____
GFR
What is the formula for Clr (renal clearance)?
Clr = Excretion rate of drug/[drug]plasma
Clr = [drug]urine x F/[drug]plasma
F = urine flow rate
What 3 things is GFR determined by?
1) PAH
2) Creatinin
3) Inulin
*Inulin is the best one
Cl(inulin) = ??
GFR
If renal clearance and GFR are equal (or close to equal) what does this mean?
- Just filtration
- No secretion
- No reabsorption
If renal clearance is a lot higher than GFR, what does this mean?
- Filtration
- Secretion
If renal clearance is a lot lower than GFR, what does this mean?
- Filtration
- Reabsorption
*probably a transporter there grabbing it and pushing it back into the blood
Bile flow = ____ mL/min
0.5-0.8
Clb = ?j
bile clearance
Clb could approach ??
500 mL/min
What does that tell you if the Clb can equal 500 mL/min but bile flow is only 0.5-0.8 mL/min?
that a lot is being excreted
MW < 300 = ____ excretion
urinary
MW > 300 = ____ excretion
biliary
List some examples of drugs excreted in the bile
- morphine
- digitoxin
- bile acids
- steroids
Describe enterohepatic recirculation
- Tablet enters small intestine
- Heads to superior Mesenteric Vein
- Portal Vein
- Liver (where glucuronidation takes place)
- Common Bile duct
- Back to small intestine
Equivalence
compares one drug product to another
Pharmaceutical equivalents
drug products that contain the same active ingredient and are identical in strength of concentration dosage form, and route of administration
Pharmaceutical alternatives
drug products that contain the same therapeutic moiety but as different salts, esters, or complexes (parent compound is the same)
Bioequivalent drug products
are pharmaceutical equivalents that have similar bioavilailbility when given in the same molar dose and studied using similar experimental conditions
Equivalency depends on the ______
condition
ex. hypertension, then the examples were equivalent because it is not life threatening
ex. cardiac arrest, the examples were not equivalent because this is a time-sensitive issue
Once you reach a ____ ____, a single dose is equivalent to a multiple dose
steady state
After __ half-lives, you will not have a drug interaction
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