Term
|
Definition
| time required for the plasma concentration of a drug to decrease by 50% |
|
|
Term
T/F
All drugs must be metabolized to be eliminated |
|
Definition
FALSE
some of the parent drug my be eliminated |
|
|
Term
| What are the major sites of excretion? |
|
Definition
|
|
Term
| What form must drugs be in in order to be eliminated via the lungs? |
|
Definition
|
|
Term
| Tublar reabsorption is passive/active diffusion? |
|
Definition
|
|
Term
| Which direction do molecules flow for tubular secretion? |
|
Definition
| From the blood into the tubular fluid |
|
|
Term
| Which direction do molecules flow for tubular reabsorption? |
|
Definition
| From the tubular fluid back into the blood |
|
|
Term
| What is the molecular weight threshold for glomerular filtration? |
|
Definition
|
|
Term
T/F
plasma protein bound drugs may be filtered if the drug is small enough |
|
Definition
FALSE
bound drugs do not undergo filtration and albumin alone weighs 69,000 (Daltons?) |
|
|
Term
| What effect does protein binding have on elimination? |
|
Definition
| It slows it but does NOT stop it from occurring |
|
|
Term
What is the most likely route for each? (tubular reabsorption or secretion)
a) lipophilic molecule
b) polar molecule
c) NH3+
d) CH3 |
|
Definition
a) lipophilic molecule- reabsorption
b) polar molecule- secretion
c) NH3+ secretion
d) CH3 reabsorption |
|
|
Term
T/F
a drug must be a substrate for secretion to occur |
|
Definition
TRUE
secretion involves carrier proteins |
|
|
Term
What transporters are involved in tubular secretion?
What molecules are substrates? |
|
Definition
OATs (Organic Anion Trans)
OCTs (Organic Cation Trans) |
|
|
Term
| After OATs and OCTs bring there charged molecules back into the tubular fluid, what assures that they wont be reabsorbed? |
|
Definition
| THey are charged so they cannot undergo passive diffusion and be reabsorbed into the blood |
|
|
Term
| How does altering the pH of tubular fluid affect elimination? |
|
Definition
| Changing the pH may allow for certain molecules to be in the ionized/ unionized form and therefore increasin/decreasing elimination |
|
|
Term
| A pt. takes a acidic drug, if the urine is alkalinized with sodium bicarb tubular reabsorption shoud______ and urinary elimination will______ |
|
Definition
Decrease
increase
(raising the pH allows for the acid to be in its ionized form. ionzed molecules are not reabsorbed and therefore more is eliminated) |
|
|
Term
T/F
Inhibition of active transporters is always bad for your body |
|
Definition
FALSE
may be clinically useful |
|
|
Term
What is the effect?
Combo of PCN (OAT substrate) and Probenecid (OAT inhibitor) |
|
Definition
PCN will stay in the blood longer aka less will be eliminated
(OATs are active transporters for secretion...inhibiting secretion into the tubular fluid allows for more to stay in the blood) |
|
|
Term
T/F
Both reabsorption and Secretion may be inhibited for clinical use because they involve transporters |
|
Definition
FALSE
Reasorption is a passive process and cannot be inhibited |
|
|
Term
| How does kidney disease affect elimination? |
|
Definition
| Decreased renal blood flow-->decrease filtration-->decreased rate of elimination |
|
|
Term
What is the deciding factor of whether a drug secreted into the blood or bile?
Be specific |
|
Definition
The molecular weight of the drug
Blood- MW<500-600
Bile- MW >500-600
(in humans) |
|
|
Term
| Metabolites entering bile are eliminated in (urine or feces)? |
|
Definition
|
|
Term
| After a drug is metabolized by the liver and enters the blood where is its next destination for elimination? |
|
Definition
| The kidneys then the urine |
|
|
Term
| How do molecules enter and exit hepatocytes? |
|
Definition
| via transport proteins because metabolites are very polar |
|
|
Term
| Pgp and MRP2 are on which membrane side of hepatocytes? Which direction do the molecules go? |
|
Definition
canicular membrane (bile)
from the cell into bile |
|
|
Term
| What transporter takes compounds from hepatocytes and into the blood? |
|
Definition
|
|
Term
T/F
enterohepatic recycling may prevent some drugs from being eliminated |
|
Definition
FALSE
it will slow it down but does NOT prevent |
|
|
Term
| Explain enterohepatic recycling? |
|
Definition
| After drugs enter the liver and are secreted into the bile, they must bypass the intestines for elimination. Since the intestine is a very absorptive organ, some drug may get reabsorbed and enter the cycle again |
|
|
Term
What is the role of Beta Glucuronidase?
How do we get this enzyme?
Does this increase or decrease elimination?
Is this process specific? |
|
Definition
It turns the metabolite back into parent drug
It is produced by bacteria in the intestine
it increases the 1/2 life
yes they are enzymes so substrate specific |
|
|
Term
| How does liver disease affect biliary and urinary elimination? |
|
Definition
a decrease in biliary elimination may cause an increase in urinary elimination.
May also inc. MRP3 (from liver to blood) |
|
|
Term
| Broad spectrum abx may destroy bacteria in the intesine. What affect may this have on reabsorption and elimination of a drug that is a glucuronide conjugate? |
|
Definition
| It will decrease reabsorption and increase elimination |
|
|
Term
What 3 things may affect pulmonary elimination?
Is this passive/active? |
|
Definition
respiration rate
pulmonary blood flow
solubility of drug in blood
passive diffusion |
|
|
Term
T/F
elimination via breast milk is an active process |
|
Definition
|
|
Term
What is the pH of breast milk?
How can this affect drug reabsorption? |
|
Definition
pH of breast milk is ~6.5
this is less than the pH of plasma so it is less likely for the drug to be reapsorbed |
|
|
Term
T/F
Some drugs may be eliminated via sweat and hair |
|
Definition
|
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