Pharmacokinetics: Volume of Distribution

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What is the advantage of using extended-release tablets for oral morphine?

Bypass of the harsh gastrointestinal environment

Faster absorption

Reduced frequency of administration (correct)

Avoidance of first-pass metabolism

What are the advantages of sublingual and buccal routes of drug absorption?

First-pass metabolism

Ease of administration

Rapid absorption (correct)

GI tract instability

When is parenteral drug administration used?

For conscious patients only

For drugs stable in the GI tract

For drugs requiring rapid onset of action (correct)

For drugs that are well-absorbed from the GI tract

What are the benefits of parenteral routes of drug administration?

High bioavailability Signup and view all the answers

What is the formula for calculating the volume of distribution (Vd)?

Vd = C0 Signup and view all the answers

In which compartment of the body is a drug effectively trapped if it has a high molecular weight or is extensively protein bound?

Plasma compartment Signup and view all the answers

Which type of drug distribution results in a low volume of distribution (Vd) that approximates the plasma volume?

Distribution into plasma compartment Signup and view all the answers

What does a low volume of distribution (Vd) indicate about the distribution of a drug in the body?

Trapping within the plasma compartment Signup and view all the answers

What is the energy source driving active transport of drugs across the cell membrane?

Hydrolysis of adenosine triphosphate (ATP) Signup and view all the answers

Which mechanism of drug absorption involves specific carrier proteins that span the cell membrane?

Active transport Signup and view all the answers

What type of absorption is used to transport drugs of exceptionally large size across the cell membrane?

Endocytosis Signup and view all the answers

Which process involves cells using vesicle formation to secrete substances out of the cell?

Exocytosis Signup and view all the answers

Which process involves drugs entering the kidney through renal arteries?

Glomerular filtration Signup and view all the answers

What is the normal glomerular filtration rate (GFR)?

125 mL/min Signup and view all the answers

What influences the passage of drugs into the glomerular filtrate?

Variations in GFR and protein binding of drugs Signup and view all the answers

Where do drugs that were not transferred into the glomerular filtrate leave the glomeruli?

Efferent arterioles Signup and view all the answers

What factor strongly influences the distribution of lipophilic drugs?

Blood flow to the area Signup and view all the answers

Which type of drug distribution may serve as a major source of the drug and prolong its actions or cause local drug toxicity?

Binding to tissue proteins Signup and view all the answers

What is the apparent volume of distribution (Vd) defined as?

The fluid volume required to contain the entire drug in the body at the same concentration measured in the plasma Signup and view all the answers

In drug distribution, drugs that accumulate in tissues may do so due to:

Binding to lipids, proteins, or nucleic acids Signup and view all the answers

In which clinical situation may a patient require a decrease in drug dosage or less frequent dosing?

Decreased metabolism due to a concomitant drug inhibiting metabolism Signup and view all the answers

Which abnormality is likely to result in an increase in drug half-life for a patient?

Decreased metabolism due to hepatic insufficiency as with cirrhosis Signup and view all the answers

What can result in the necessity of higher doses or more frequent dosing intervals for a drug?

Increased hepatic blood flow Signup and view all the answers

What factors influence the distribution of a drug from the plasma to the interstitium?

Blood flow, capillary permeability, tissue volume, binding of the drug to plasma and tissue proteins, and relative lipophilicity of the drug Signup and view all the answers

Why does propofol rapidly distribute into the central nervous system (CNS) when administered intravenously?

High blood flow and high lipophilicity of propofol Signup and view all the answers

What determines capillary permeability in the process of drug distribution?

Capillary structure and chemical nature of the drug Signup and view all the answers

Which factor partly explains the short duration of hypnosis produced by an IV bolus of propofol?

Variation in blood flow to tissue capillaries Signup and view all the answers

What does the volume of distribution (Vd) indicate about a drug that has a low Vd?

The drug has a low Vd that approximates the plasma volume Signup and view all the answers

In which compartment of the body would a drug with a low molecular weight but is hydrophilic distribute into?

Interstitial fluid Signup and view all the answers

What factor could lead to a drug having a high volume of distribution (Vd)?

Extensive protein binding and high molecular weight Signup and view all the answers

What does the volume of distribution (Vd) compare the distribution of a drug with?

Volumes of the water compartments in the body Signup and view all the answers

Why is the rectal route of drug administration advantageous in preventing drug destruction in the gastrointestinal (GI) environment?

Because it bypasses the portal circulation and minimizes biotransformation by the liver Signup and view all the answers

What is a significant disadvantage of the rectal route of drug administration?

Erratic and incomplete absorption of drugs Signup and view all the answers

How does the rate and extent of drug absorption vary for routes of administration other than intravenous?

They result in lower bioavailability due to incomplete absorption Signup and view all the answers

What does the absorption of drugs involve?

Transfer of a drug from the site of administration to the bloodstream Signup and view all the answers

What type of distribution does aminoglycoside antibiotics exhibit?

Distribution into the extracellular fluid Signup and view all the answers

What does a larger volume of distribution (Vd) generally indicate?

Greater distribution into tissues Signup and view all the answers

How is the apparent Vd defined?

Volume of drug distributed into the extracellular fluid Signup and view all the answers

What allows for the calculation of Vd in drug clearance?

First order drug elimination Signup and view all the answers

Which type of drug kinetics is most commonly observed for drug elimination?

First-order kinetics Signup and view all the answers

What allows the kidney to efficiently eliminate lipophilic drugs?

Increased polarity due to metabolism Signup and view all the answers

Which general set of reactions in the liver leads to the conversion of lipid-soluble agents into more polar substances?

Phase I and phase II reactions Signup and view all the answers

What must drugs be sufficiently polar to be, in order to be eliminated from the body?

Eliminated through urinary excretion Signup and view all the answers

What are the factors that influence the distribution of a drug from the plasma to the interstitium?

All of the above Signup and view all the answers

Why does propofol rapidly distribute into the central nervous system (CNS) when administered intravenously?

High blood flow and high lipophilicity Signup and view all the answers

What may partly explain the short duration of hypnosis produced by an IV bolus of propofol?

Low blood flow to skeletal muscles Signup and view all the answers

What determines capillary permeability in the process of drug distribution?

Capillary structure and chemical nature of the drug Signup and view all the answers

Pharmacokinetics: Volume of Distribution

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Questions and Answers

What is the advantage of using extended-release tablets for oral morphine?

What are the advantages of sublingual and buccal routes of drug absorption?

When is parenteral drug administration used?

What are the benefits of parenteral routes of drug administration?

What is the formula for calculating the volume of distribution (Vd)?

In which compartment of the body is a drug effectively trapped if it has a high molecular weight or is extensively protein bound?

Which type of drug distribution results in a low volume of distribution (Vd) that approximates the plasma volume?

What does a low volume of distribution (Vd) indicate about the distribution of a drug in the body?

What is the energy source driving active transport of drugs across the cell membrane?

Which mechanism of drug absorption involves specific carrier proteins that span the cell membrane?

What type of absorption is used to transport drugs of exceptionally large size across the cell membrane?

Which process involves cells using vesicle formation to secrete substances out of the cell?

Which process involves drugs entering the kidney through renal arteries?

What is the normal glomerular filtration rate (GFR)?

What influences the passage of drugs into the glomerular filtrate?

Where do drugs that were not transferred into the glomerular filtrate leave the glomeruli?

What factor strongly influences the distribution of lipophilic drugs?

Which type of drug distribution may serve as a major source of the drug and prolong its actions or cause local drug toxicity?

What is the apparent volume of distribution (Vd) defined as?

In drug distribution, drugs that accumulate in tissues may do so due to:

In which clinical situation may a patient require a decrease in drug dosage or less frequent dosing?

Which abnormality is likely to result in an increase in drug half-life for a patient?

What can result in the necessity of higher doses or more frequent dosing intervals for a drug?

What factors influence the distribution of a drug from the plasma to the interstitium?

Why does propofol rapidly distribute into the central nervous system (CNS) when administered intravenously?

What determines capillary permeability in the process of drug distribution?

Which factor partly explains the short duration of hypnosis produced by an IV bolus of propofol?

What does the volume of distribution (Vd) indicate about a drug that has a low Vd?

In which compartment of the body would a drug with a low molecular weight but is hydrophilic distribute into?

What factor could lead to a drug having a high volume of distribution (Vd)?

What does the volume of distribution (Vd) compare the distribution of a drug with?

Why is the rectal route of drug administration advantageous in preventing drug destruction in the gastrointestinal (GI) environment?

What is a significant disadvantage of the rectal route of drug administration?

How does the rate and extent of drug absorption vary for routes of administration other than intravenous?

What does the absorption of drugs involve?

What type of distribution does aminoglycoside antibiotics exhibit?

What does a larger volume of distribution (Vd) generally indicate?

How is the apparent Vd defined?

What allows for the calculation of Vd in drug clearance?

Which type of drug kinetics is most commonly observed for drug elimination?

What allows the kidney to efficiently eliminate lipophilic drugs?

Which general set of reactions in the liver leads to the conversion of lipid-soluble agents into more polar substances?

What must drugs be sufficiently polar to be, in order to be eliminated from the body?

What are the factors that influence the distribution of a drug from the plasma to the interstitium?

Why does propofol rapidly distribute into the central nervous system (CNS) when administered intravenously?

What may partly explain the short duration of hypnosis produced by an IV bolus of propofol?

What determines capillary permeability in the process of drug distribution?

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