Section 1 - Quiz Questions Flashcards by Kaitlin Monson

Peripheral vasoconstriction will slow the absorption of a drug administered by which route?

Subcutaneous

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Three formulations of the same generic drug are bioequivalent if:

The areas under their plasma drug concentration x time curves are equal when they are given by the same route of administration.

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Which statement about oral drug absorption is correct?

Drugs given orally to ruminants become concentrated in the alkaline fluids of the rumen and thus more readily absorbed in the intestine

Drugs that are weka bases are absorbed more rapidly than cidic drugs when they enter the gastric fluids of a cat

Most drugs are completely absorbed it he oral cavity when ingested

In dogs and cats, fat ingestion delays the absorption of basic drugs by slowing drug passage from stomach to the intestine

Which statement about oral drug absorption is correct?

Drugs given orally to ruminants become concentrated in the alkaline fluids of the rumen and thus more readily absorbed in the intestine

Drugs that are weka bases are absorbed more rapidly than cidic drugs when they enter the gastric fluids of a cat

Most drugs are completely absorbed it he oral cavity when ingested

In dogs and cats, fat ingestion delays the absorption of basic drugs by slowing drug passage from stomach to the intestine

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True/False

Drug binding to albumin only occurs with neutral or weakly basic drugs

True/False

Drug binding to albumin only occurs with neutral or weakly basic drugs

**FALSE **

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True/False

Abrupt increases in plasma drug concentrations are unlikely to occur as the result of sudden drug displacement from binding sites on plasma proteins because of rapid “free” drug elimination in vivo.

True/False

TRUE

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True/False

The fraction of an acidic drug that is bound to alpha-acid glycoprotein is greater than to albumin

True/False

The fraction of an acidic drug that is bound to alpha-acid glycoprotein is greater than to albumin

FALSE

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A drug given to a dairy cow is a weak base with a pKa = 8.8. Some of this drug appears in the cow’s milk (pH = 6.8). What is the ratio of ionized to non-ionized drug in her milk?

[HA]/[A-} or [BH+]/[B] = 10pKa-pH

A drug given to a dairy cow is a weak base with a pKa = 8.8. Some of this drug appears in the cow’s milk (pH = 6.8). What is the ratio of ionized to non-ionized drug in her milk?

[HA]/[A-} or [BH+]/[B] = 10pKa-pH

100:1

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Is this statement true/false regarding a drug’s volume of distribution (V_d)?

Drugs with a large Vd are less easily removed from the plasma by hemodialysis

Is this statement true/false regarding a drug’s volume of distribution (Vd)?

Drugs with a large Vd are less easily removed from the plasma by hemodialysis

TRUE!

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**Is this statement true/false regarding a drug’s volume of distribution (Vd)?

A drug must be widely and equally distributed throughout the body in order to have a large Vd **

Is this statement true/false regarding a drug’s volume of distribution (Vd)?

**A drug must be widely and equally distributed throughout the body in order to have a large Vd **

FALSE

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Is this statement true/false regarding a drug’s volume of distribution (Vd)?

Drugs highly bound to plasma proteins typically have a large Vd

Is this statement true/false regarding a drug’s volume of distribution (Vd)?

Drugs highly bound to plasma proteins typically have a large Vd

FALSE

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Is this statement true/false regarding a drug’s volume of distribution (Vd)?

Lipophilic, basic drugs have a smaller Vd than hydrophilic, acidic drugs

Is this statement true/false regarding a drug’s volume of distribution (Vd)?

Lipophilic, basic drugs have a smaller Vd than hydrophilic, acidic drugs

FALSE

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Organ with the greatest surface area for drug absorption

Intestine

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Organ with the greatest drug biotransformation activity

Liver

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**Organ with the highest blood perfusion rate (ml blood/min per 100 gm weight) **

Kidneys

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In which zone of the liver lobule are the enzymes for each drug biotransformation system more highly expressed?

1. Glucoronidation

**2. Microsomal Oxidation **

**3. Sulfation **

In which zone of the liver lobule are the enzymes for each drug biotransformation system more highly expressed?

**1. Glucoronidation - Zone 3 (centrilobular) **

**2. Microsomal Oxidation - Zone 3 (centrilobular) **

**3. Sulfation - Zone 1 (periportal) **

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_True/False
regarding cytochrome P450 (mixed-function oxidase) system_

**Cytochrome P450 is located in liver microsomes and cytochrome P450 reductase is expressed in neighboring mitochondria **

_True/False
regarding cytochrome P450 (mixed-function oxidase) system_

**Cytochrome P450 is located in liver microsomes and cytochrome P450 reductase is expressed in neighboring mitochondria **

FALSE

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_True/False
regarding cytochrome P450 (mixed-function oxidase) system_

**Cytochrome P450 enzymes function exclusively to biotransform drug molecules **

_True/False
regarding cytochrome P450 (mixed-function oxidase) system_

**Cytochrome P450 enzymes function exclusively to biotransform drug molecules **

FALSE

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_True/False
regarding cytochrome P450 (mixed-function oxidase) system_

**Cytochrome P450 reductase mediates the transfer of electrons to heme iron in cytochrome P450 mono-oxygenases **

_True/False
regarding cytochrome P450 (mixed-function oxidase) system_

**Cytochrome P450 reductase mediates the transfer of electrons to heme iron in cytochrome P450 mono-oxygenases **

TRUE!

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_True/False
Regarding the cytochrome P450 (mixed-function oxidase) system_

Monoamine oxidase and ethanol dehydrogenase are members of the cytochrome P450 enzyme superfamily

_True/False
Regarding the cytochrome P450 (mixed-function oxidase) system_

Monoamine oxidase and ethanol dehydrogenase are members of the cytochrome P450 enzyme superfamily

FALSE

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Which domestic and wild animal pair is known to have a non-functional UDP-glucuronyltransferase gene?

House cat (Felius catus) and lion (Panthera leo)

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Which process involves the deconjugation of a drug metabolite in the intestinal tract?

Enterohepatic recycling

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Which is the most common route of drug excretion?

Urine

**Drugs that are bound reversibly to plasma albumin can enter the urine through: **

Active secretion

Which animal is the greatest excretor of drugs by the biliary route, based on its relative bile flow and ability to transport drugs into the bile that are in the 300-500 molecular weight range?

Rat

**The half-life of a drug will be shorter if there is a decrease in its: **

**The half-life of a drug will be shorter if there is a decrease in its: ** Volume of distribution

**A drug with a half life of 7 hours is given at a fixed dose by constant rate intravenous infusion. In approximately how many hours will plasma concentrations of this drug first begin to plateau at a steady-state concentration?**

**_True/False regarding drug administration and dosing_** **The loading dose, not the maintenance dose of a drug determines the plasma drug concentration at steady-state**

**_True/False regarding drug administration and dosing_** ## Footnote **The loading dose, not the maintenance dose of a drug determines the plasma drug concentration at steady-state** FALSE

**_True/False regarding drug administration and dosing_** **Increasing the rate of continuous intravenous drug infusion will shorten the time required to achieve a steady-state plasma drug concentration **

**_True/False regarding drug administration and dosing_** ## Footnote **Increasing the rate of continuous intravenous drug infusion will shorten the time required to achieve a steady-state plasma drug concentration ** FALSE

**_True/False regarding drug administration and dosing_** **The shorter a drug's half-life is compared to its dosing interval, the greater the variability in plasma drug concentration (larger peak and trough) **

**_True/False regarding drug administration and dosing_** ## Footnote **The shorter a drug's half-life is compared to its dosing interval, the greater the variability in plasma drug concentration (larger peak and trough) ** TRUE

**_Which class of drug receptor best fits:_** ***Comprised of multiple protein subunits; its activation by ligands is associated with rapid changes in cell membrane potential ***

**_Which class of drug receptor best fits:_** ## Footnote **Comprised of multiple protein subunits; its activation by ligands is associated with rapid changes in cell membrane potential** Ligand-Gated Ion Channel

**_Which class of drug receptor best fits:_** **An intracellular receptor that recognized lipid-soluble ligands and can bind to DNA**

**_Which class of drug receptor best fits:_** ## Footnote **An intracellular receptor that recognized lipid-soluble ligands and can bind to DNA** Nuclear factor receptor

**_Which class of drug receptor best fits:_** **A single receptor protein that spans the cell membrane seven times**

**_Which class of drug receptor best fits:_** ## Footnote **A single receptor protein that spans the cell membrane seven times** G Protein-Coupled Receptor

**_Which class of drug receptor best fits:_** **A single protein that spans the cell membrane once and has an intracellular catalytic domain which is unveiled when the receptor is activated by a ligand**

**_Which class of drug receptor best fits:_** ## Footnote **A single protein that spans the cell membrane once and has an intracellular catalytic domain which is unveiled when the receptor is activated by a ligand** Kinase-Linked Receptor

**The therapeutic index of a drug is defined as: **

**The therapeutic index of a drug is defined as: ** The 50% lethal dose divided by the 50% effective dose

**What is the mode by which most drugs are distributed in the body?**

**What is the mode by which most drugs are distributed in the body?** Passive Diffusion

**Enterohepatic recycling of a glucuronidated drug from the intestinal tract depends upon the presence of ________ in intestinal epithelial cells. **

**Enterohepatic recycling of a glucuronidated drug from the intestinal tract depends upon the presence of ________ in intestinal epithelial cells. ** B-Glucuronidase

**An acidic drug with a pKa = 2.4 is given intravenously to a cat. What is the ratio of the protonated (non-ionized) to unprotonated (ionized) forms of the drug in the plasma?**

**An acidic drug with a pKa = 2.4 is given intravenously to a cat. What is the ratio of the protonated (non-ionized) to unprotonated (ionized) forms of the drug in the plasma?** 1 : 100,000

**What type of drug decreases the protency of an agonist by a surmountable mechanism?**

**What type of drug decreases the protency of an agonist by a surmountable mechanism?** Competitive Orthosteric Antagonist

**Name the drug biotransformation process that matches this statement ** Inactivation process for norepinephrine and other biogenic amine neurotransmitters

**Name the drug biotransformation process that matches this statement** ## Footnote Inactivation process for norepinephrine and other biogenic amine neurotransmitters **_Monoamine Oxidase_**

**Name the drug biotransformation process that matches this statement** This process requires UDP-glucose

**Name the drug biotransformation process that matches this statement** ## Footnote This process requires UDP-glucose **_Glucuronic Acid Conjugation_**

**Name the drug biotransformation process that matches this statement** Drug biotransformations occur through the chemical reduction of molecular oxygen and an iron atom

**Name the drug biotransformation process that matches this statement** ## Footnote Drug biotransformations occur through the chemical reduction of molecular oxygen and an iron atom **_Mixed-Function Oxidase System_**

**Name the drug biotransformation process that matches this statement** A phase I biotransformation process that can be mediated by cytochrome P450 system or by enzymes expressed by gut bacteria

**Name the drug biotransformation process that matches this statement** ## Footnote A phase I biotransformation process that can be mediated by cytochrome P450 system or by enzymes expressed by gut bacteria **_Reduction_**

**Name the drug biotransformation process that matches this statement** Pigs lack sufficient amounts of the cofactor needed to operate this phase II mechanism at a high level

**Name the drug biotransformation process that matches this statement** ## Footnote Pigs lack sufficient amounts of the cofactor needed to operate this phase II mechanism at a high level **_Sulfate conjugation _**

**Glucuronidation increases renal excretion of a drug molecule by active secretion through the ______ transport pathway into the renal tubule. **

**Glucuronidation increases renal excretion of a drug molecule by active secretion through the ______ transport pathway into the renal tubule. ** Acid (anion)

**Drugs given to a lactating animal which are relatively _______ will tend to accumulate in her milk.**

**Drugs given to a lactating animal which are relatively \_\_\_\_\_\_\_ will tend to accumulate in her milk.** Basic (Milk is slightly more acidic than plasma, and basic drugs would have a greater ionized fraction in this environment

**What is the approximate half-life (in hours) of a drug who Vd = 143 L and clearance = 5 L/hr?**

**What is the approximate half-life (in hours) of a drug who Vd = 143 L and clearance = 5 L/hr?** 20 hours (Half life = 0.7 Vd/Cl)

**_True/False _** The loading dose of a drug given by bolus injection is usually higher than the maintenance dose.

**_True/False_** ## Footnote The loading dose of a drug given by bolus injection is usually higher than the maintenance dose. **TRUE**

**Drugs given to a pregnant animal which are relatively ______ will tend to accumulate more in the fetal circulation**

**Drugs given to a pregnant animal which are relatively ______ will tend to accumulate more in the fetal circulation** Basic (Fetal blood is slightly more acidic than maternal blood, and acidic drugs would have a greater non-ionized fraction in this environment)

**A drug has a half-life of 3 hours and is given at a total bolus dose of 10 mg, i.c. to a dog. Assuming that the drug is eliminated by first-order kinetics, in how many hours will the amount of drug in the dog's body reach 2.5 mg?**

**Bioavailability = **

**Bioavailability = ** Comparison of a drug's plasma concentration vs. time relationships after its administration at a fixed dose by the intravenous route and an extravascular route

**Volume of distribution = **

**Volume of distribution = ** Measure of a drug's theoretical dilution space in the body

**Bioequivalence = **

**Bioequivalence = ** Comparison of the plasma concentration vs. time relationships for two or more formulations of the same generic drug administered by the same route and dose

**Total Body Clearance = **

**Total Body Clearance =** Rate at which a fixed volume of plasma is cleansed of a drug