Pharmacokinetics 4 Flashcards

1
Q

Co-administration of which drug reduces the observed potency of codeine?
a. diltiazem
b. fluoxetine
c. phenytoin
d. rifampin

A

B. fluoxetine

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2
Q

The ________ is the most important mechanism of drug biotransformation in the body.

A

P450 system

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3
Q

_________ can influence the enzymatic activity of the P450 system.

A

Exogenous chemicals

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4
Q

_________ stimulate the synthesis of additional enzymes

A

Enzyme inducers

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5
Q

Enzyme inducers _______ drug clearance

A

increase

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6
Q

Common enzyme inducers include

A

ethanol
tobacco
phenytoin
barbiturates
rifampin
carbamazepine

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7
Q

_____ compete for binding sites on the enzymes

A

Enzyme inhibitors

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8
Q

Enzyme inhibitors ______ drug clearance.

A

reduce

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9
Q

Common enzyme inhibitors include

A

SSRIs, omeprazole, and grapefruit juice
isoniazid, ketoconazole, erythromycin, cimetidine

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10
Q

The most important cytochrome P450 enzyme is

A

CYP 3A4 (metabolizes nearly 50% of the drugs we administer)

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11
Q

The P450 system carries out most of the body’s ______ biotransformations.

A

phase 1

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12
Q

The P450 enzymes are located in the

A

smooth endoplasmic reticulum of the hepatocyte
also located in extrahepatic tissue such as the lung, kidneys, skin, adrenal gland, and GI tract

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13
Q

________ contribute to variations in enzyme efficiency, and this can affect the observed drug potency from patient to patient.

A

Genetic polymorphisms

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14
Q

Which statement regarding renal clearance is true?
a. acidic urine promotes thiopental excretion
b. basic urine enhances morphine reabsorption
c. protein-bond drugs are filtered at the glomerulus
d. organic anion transporters secrete drug into the distal convoluted tubule

A

b. basic urine enhances morphine reabsorption
morphine is a weak base; as a weak base, the non-ionized fraction increases in an alkalotic environment; therefore, basic urine enhances morphine reabsorption

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15
Q

What two processes deliver a drug to the renal tubule?

A

glomerular filtration
organic ion transporters

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16
Q

__________ are resistant to glomerular filtration.

A

Highly protein-bound drugs

17
Q

_________ in the ultrafiltrate tend to be eliminated in the urine.

A

Hydrophilic drugs

18
Q

___________ in the ultrafiltrate tend to get reabsorbed into the peritubular fluid.

A

Liphophilic

19
Q

Renal clearance is determined by the drug’s

A

polarity and the pH of the ultrafiltrate

20
Q

Clearance of drugs such as furosemide, morphine, and dopamine rely on

A

organic ion transporters located in the proximal renal tubules

21
Q

__________ influences whether drugs are excreted in the urine or reabsorbed into the peritubular capillaries.

22
Q

In terms of urine pH and elimination, remember that

A

like dissolves like!

23
Q

Acidic urine favors ________ of acid drugs and _______ of basic drugs

A

reabsorption; excretion

24
Q

Basic urine favors _______ of basic drugs and ______ of acidic drugs

A

reabsorption; excretion

25
Liphophilic drugs must _________ before they can be excreted by the kidneys.
undergo biotransformation reactions to increase their water solubility
26
Drugs that are not bound to plasma proteins will be __________ by the glomerulus.
freely filtered
27
Organic anion transporters (OAT) includes
furosemide, thiazide diuretics, and penicillin
28
Organic cation transporters (OCT) include
morphine, meperidine, and dopamine
29
What two things will acidify the urine?
ammonium chloride or cranberry juice
30
Acidifying the urine will help to
eliminate basic drugs
31
What two things will alkalize the urine?
sodium bicarbonate or acetazolamide
32
Identify the drugs that are metabolized by nonspecific plasma esterases. (select 3) a. esmolol b. atracurium c. cocaine d. remifentanil e. succinylcholine f. fospropofol
a. esmolol b. atracurium d. remifentanil
33
Enzymatic drug metabolism in the plasma tends to occur via one of three pathways which include
pseudocholinesterase nonspecific esterases alkaline phsophatase
34
Unlike hepatic enzymes, plasma enzymes do not
undergo enzyme induction
35
Examples of drugs that undergo pseudocholinesterase metabolism include
ester-type local anesthetics, mivacurium, and succinylcholine
36
Examples of drugs that undergo alkaline phosphatase metabolism include
fospropofol
37
Examples of drugs that undergo nonspecific esterases metabolism include
remifentanil, esmolol, clevidipine, and atracurium remimazolam, & etomidate (+ hepatic)
38
Drugs that undergo Hoffman elimination include
cisatracurium and atracurium (to some degree)
39
___________ extends the duration of action of succinylcholine, mivacurium, cocaine, and ester local anesthetics.
Pseudocholinesterase deficiency