Podcast
Questions and Answers
Which of the following best defines drug absorption?
Which of the following best defines drug absorption?
- The breakdown of the drug in the gastrointestinal tract
- The movement of the drug out of the bloodstream after administration
- The metabolism of the drug within the bloodstream
- The movement of the drug into the bloodstream after administration (correct)
What controls drug absorption?
What controls drug absorption?
- Pores and large plasma proteins
- Barriers like blood-brain barriers and placenta
- Capillary walls and endothelial cells (correct)
- Cell membrane and basement membrane
Where does the exchange of materials between blood and cells primarily occur?
Where does the exchange of materials between blood and cells primarily occur?
- Capillaries (correct)
- Basement membrane
- Endothelial cells
- Cell membrane
Which of the following types of capillaries has more pores allowing materials to move in/out?
Which of the following types of capillaries has more pores allowing materials to move in/out?
What is the site of exchange of materials between blood and cells?
What is the site of exchange of materials between blood and cells?
How thick are capillary walls?
How thick are capillary walls?
What allows ions, water, nutrients, and unbound drugs to move in/out of capillaries?
What allows ions, water, nutrients, and unbound drugs to move in/out of capillaries?
Which pathway of drug excretion is the most important?
Which pathway of drug excretion is the most important?
Under what condition will there be a greater intensity of drug effect?
Under what condition will there be a greater intensity of drug effect?
What does the Volume Distribution Formula Vd= Amount of drug in the body/Plasma drug concentration represent?
What does the Volume Distribution Formula Vd= Amount of drug in the body/Plasma drug concentration represent?
Which drug excretion pathway involves enterohepatic cycling for some drugs?
Which drug excretion pathway involves enterohepatic cycling for some drugs?
In what type of urine are acid drugs mostly ionized?
In what type of urine are acid drugs mostly ionized?
Which category of FDA Teratogenic Risk indicates absolute fetal abnormalities and not to be used at any time during pregnancy?
Which category of FDA Teratogenic Risk indicates absolute fetal abnormalities and not to be used at any time during pregnancy?
What is the effect on drug excretion during the first year of life in neonates/infants?
What is the effect on drug excretion during the first year of life in neonates/infants?
Which organ is primarily responsible for the excretion of general anesthetic gases?
Which organ is primarily responsible for the excretion of general anesthetic gases?
What happens to measures of renal function with age?
What happens to measures of renal function with age?
What occurs to drug excretion after the first year of life in neonates/infants?
What occurs to drug excretion after the first year of life in neonates/infants?
Which factor does NOT influence the rate of drug absorption?
Which factor does NOT influence the rate of drug absorption?
In aging individuals, what contributes to decreased drug absorption?
In aging individuals, what contributes to decreased drug absorption?
Which organ is exposed to the largest amount of drug due to high blood flow?
Which organ is exposed to the largest amount of drug due to high blood flow?
What happens to water-soluble drugs in the body due to their solubility in water and plasma?
What happens to water-soluble drugs in the body due to their solubility in water and plasma?
How does aging affect drug binding to plasma proteins?
How does aging affect drug binding to plasma proteins?
What does a lower percentage of body fat in neonates and infants result in regarding drug distribution?
What does a lower percentage of body fat in neonates and infants result in regarding drug distribution?
What effect does a higher percentage of water in pediatrics have on drug concentrations?
What effect does a higher percentage of water in pediatrics have on drug concentrations?
What is the impact of high drug binding on drug distribution into tissues and metabolism?
What is the impact of high drug binding on drug distribution into tissues and metabolism?
What is the main function of the blood-brain barrier (BBB) in relation to drug absorption?
What is the main function of the blood-brain barrier (BBB) in relation to drug absorption?
What is most influential in the rapid distribution of drugs into body tissues?
What is most influential in the rapid distribution of drugs into body tissues?
In drug excretion, which type of drugs are mostly ionized in alkaline urine?
In drug excretion, which type of drugs are mostly ionized in alkaline urine?
What is the primary pathway for the excretion of general anesthetic gases?
What is the primary pathway for the excretion of general anesthetic gases?
During the first year of life, what happens to drug excretion in neonates/infants?
During the first year of life, what happens to drug excretion in neonates/infants?
What is the impact of high drug binding on drug distribution into tissues and metabolism?
What is the impact of high drug binding on drug distribution into tissues and metabolism?
What is the category of FDA Teratogenic Risk that indicates absolute fetal abnormalities and prohibits use at any time during pregnancy?
What is the category of FDA Teratogenic Risk that indicates absolute fetal abnormalities and prohibits use at any time during pregnancy?
How does aging affect measures of renal function such as GFR and creatinine clearance?
How does aging affect measures of renal function such as GFR and creatinine clearance?
What occurs to water-soluble drugs in the body due to their solubility in water and plasma?
What occurs to water-soluble drugs in the body due to their solubility in water and plasma?
In what type of urine are acid drugs mostly ionized?
In what type of urine are acid drugs mostly ionized?
What does the Volume Distribution Formula Vd= Amount of drug in the body/Plasma drug concentration represent?
What does the Volume Distribution Formula Vd= Amount of drug in the body/Plasma drug concentration represent?
Which organ is exposed to the largest amount of drug due to high blood flow?
Which organ is exposed to the largest amount of drug due to high blood flow?
Which factor does NOT influence the rate of drug distribution?
Which factor does NOT influence the rate of drug distribution?
What happens to water-soluble drugs in the body due to their solubility in water and plasma?
What happens to water-soluble drugs in the body due to their solubility in water and plasma?
What is the effect of a higher percentage of water in pediatrics on drug concentrations?
What is the effect of a higher percentage of water in pediatrics on drug concentrations?
How does aging affect drug binding to plasma proteins?
How does aging affect drug binding to plasma proteins?
What is most influential in the rapid distribution of drugs into body tissues?
What is most influential in the rapid distribution of drugs into body tissues?
Where does the exchange of materials between blood and cells primarily occur?
Where does the exchange of materials between blood and cells primarily occur?
What happens to drug excretion after the first year of life in neonates/infants?
What happens to drug excretion after the first year of life in neonates/infants?
Which drug excretion pathway involves enterohepatic cycling for some drugs?
Which drug excretion pathway involves enterohepatic cycling for some drugs?
What does a lower percentage of body fat in neonates and infants result in regarding drug distribution?
What does a lower percentage of body fat in neonates and infants result in regarding drug distribution?
What category of FDA Teratogenic Risk indicates absolute fetal abnormalities and not to be used at any time during pregnancy?
What category of FDA Teratogenic Risk indicates absolute fetal abnormalities and not to be used at any time during pregnancy?
What is the primary site of exchange of materials between blood and cells?
What is the primary site of exchange of materials between blood and cells?
Which of the following barriers allows a large part of the basement membrane to be exposed, allowing large plasma proteins to pass through?
Which of the following barriers allows a large part of the basement membrane to be exposed, allowing large plasma proteins to pass through?
What regulates drug absorption by controlling the movement of the drug into the bloodstream after administration?
What regulates drug absorption by controlling the movement of the drug into the bloodstream after administration?
Which part of the body has capillary walls that are one cell thick, with pores allowing materials to move in and out?
Which part of the body has capillary walls that are one cell thick, with pores allowing materials to move in and out?
What is the role of capillaries in relation to drug absorption?
What is the role of capillaries in relation to drug absorption?
Which organ is exposed to the largest amount of drug due to high blood flow?
Which organ is exposed to the largest amount of drug due to high blood flow?
What controls drug absorption by regulating the movement of drugs into the bloodstream after administration?
What controls drug absorption by regulating the movement of drugs into the bloodstream after administration?
Which type of capillaries has more pores allowing materials to move in and out?
Which type of capillaries has more pores allowing materials to move in and out?
What allows ions, water, nutrients, and unbound drugs to move in/out of capillaries?
What allows ions, water, nutrients, and unbound drugs to move in/out of capillaries?
What is mainly responsible for controlling drug absorption by regulating the movement of drugs into the bloodstream after administration?
What is mainly responsible for controlling drug absorption by regulating the movement of drugs into the bloodstream after administration?
Study Notes
-
Drug Absorption: Blood-Brain-Barrier (BBB) acts as a selective barrier for large hydrophilic molecules, only allowing passage of smaller, lipid-soluble drugs or through active transport.
-
To enter the brain, drugs must pass through endothelial cells or undergo active transport. Levodopa, a specific drug, is transported into the brain via a transporter.
-
The rate of drug absorption is influenced by factors such as:
- Surface area of absorption site
- Blood flow at absorption site
- Concentration gradient
- Drug formulations (sizes)
- Lipid solubility
- Un-ionized state
-
In neonates and infants:
- Smaller muscle mass results in slower absorption after IM injections
- Thinner skin allows for faster absorption of topically applied drugs
- Less acidic gastrointestinal tract
-
In aging individuals:
- Decreased intestinal surface area
- Decreased blood flow to the intestine
- Decreased gastrointestinal motility
- Decreased onset of action
- Decreased absorption of medications
-
Drug Distribution: After a drug gains access to the bloodstream, it is distributed to various tissues and organs of the body.
-
Factors affecting Drug Distribution:
- Blood flow: Tissues with high blood flow, such as the brain, liver, kidneys, and lungs, are exposed to the largest amount of drug.
- Blood-Brain Barrier: Brain composition of a large amount of lipid allows for lipid-soluble drugs to pass readily into the brain.
- Plasma Protein Binding: The distribution of drugs in the body is influenced by the percentage bound to plasma proteins. A higher percentage of binding reduces the free drug available for distribution into tissues.
- Distribution occurs most rapidly into tissues with high blood flow, such as "rich-vessel organs" (lungs, kidneys, liver, brain).
-
Water-soluble drugs vs. fat-soluble drugs:
- Water-soluble drugs are more easily distributed throughout the body due to their solubility in water and plasma.
- Fat-soluble drugs are stored in fatty tissues, acting as a drug reservoir, and are released into the bloodstream over a longer period of time.
-
Drug Binding:
- Drugs bound to plasma proteins are generally not pharmacologically active and have longer durations of action and low volumes of distribution.
- Aging reduces plasma protein levels, leading to increased free drug, decreased drug metabolism, and increased drug effect.
- Neonates and infants have a lower percentage of body fat, resulting in decreased distribution to body tissues and longer drug effects.
- Pediatrics have a higher percentage of water and are more easily dehydrated, leading to increased drug concentrations.
- High drug binding reduces the free drug available for distribution into tissues, decreases metabolism, and can be displaced by other drugs.
-
Drug Absorption: Blood-Brain-Barrier (BBB) acts as a selective barrier for large hydrophilic molecules, only allowing passage of smaller, lipid-soluble drugs or through active transport.
-
To enter the brain, drugs must pass through endothelial cells or undergo active transport. Levodopa, a specific drug, is transported into the brain via a transporter.
-
The rate of drug absorption is influenced by factors such as:
- Surface area of absorption site
- Blood flow at absorption site
- Concentration gradient
- Drug formulations (sizes)
- Lipid solubility
- Un-ionized state
-
In neonates and infants:
- Smaller muscle mass results in slower absorption after IM injections
- Thinner skin allows for faster absorption of topically applied drugs
- Less acidic gastrointestinal tract
-
In aging individuals:
- Decreased intestinal surface area
- Decreased blood flow to the intestine
- Decreased gastrointestinal motility
- Decreased onset of action
- Decreased absorption of medications
-
Drug Distribution: After a drug gains access to the bloodstream, it is distributed to various tissues and organs of the body.
-
Factors affecting Drug Distribution:
- Blood flow: Tissues with high blood flow, such as the brain, liver, kidneys, and lungs, are exposed to the largest amount of drug.
- Blood-Brain Barrier: Brain composition of a large amount of lipid allows for lipid-soluble drugs to pass readily into the brain.
- Plasma Protein Binding: The distribution of drugs in the body is influenced by the percentage bound to plasma proteins. A higher percentage of binding reduces the free drug available for distribution into tissues.
- Distribution occurs most rapidly into tissues with high blood flow, such as "rich-vessel organs" (lungs, kidneys, liver, brain).
-
Water-soluble drugs vs. fat-soluble drugs:
- Water-soluble drugs are more easily distributed throughout the body due to their solubility in water and plasma.
- Fat-soluble drugs are stored in fatty tissues, acting as a drug reservoir, and are released into the bloodstream over a longer period of time.
-
Drug Binding:
- Drugs bound to plasma proteins are generally not pharmacologically active and have longer durations of action and low volumes of distribution.
- Aging reduces plasma protein levels, leading to increased free drug, decreased drug metabolism, and increased drug effect.
- Neonates and infants have a lower percentage of body fat, resulting in decreased distribution to body tissues and longer drug effects.
- Pediatrics have a higher percentage of water and are more easily dehydrated, leading to increased drug concentrations.
- High drug binding reduces the free drug available for distribution into tissues, decreases metabolism, and can be displaced by other drugs.
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Description
Test your knowledge of drug absorption, distribution, and excretion with this quiz based on the fundamentals of pharmacology lecture by Hoang Nguyen, M.D., Ph.D., RPh., FACHE. Assess your understanding of mechanisms and learning objectives related to pharmacokinetics.
