Absorption Flashcards
What is the definition of drug absorption?
A) The passage of a drug into the systemic circulation
B) The elimination of a drug from the body
C) The binding of a drug to plasma proteins
D) The conversion of a drug into its active metabolite
A
A drug with a pKa of 3.5 will be absorbed more efficiently in which part of the body?
A) Duodenum (pH 6)
B) Stomach (pH 2)
C) Colon (pH 7)
D) Blood plasma (pH 7.4)
B
Which of the following is the most common mechanism for drug absorption?
A) Active transport
B) Passive diffusion
C) Endocytosis
D) Facilitated diffusion
B
The rate of passive diffusion depends on which of the following factors?
A) Lipid solubility of the drug
B) The size of the drug molecule
C) The concentration gradient across the membrane
D) All of the above
D
What is the role of pH in drug absorption?
A) It determines the ionization state of the drug
B) It has no effect on drug permeability
C) It only affects hydrophobic drugs
D) It increases the molecular weight of the drug
A
Which of the following is TRUE regarding facilitated diffusion?
A) It requires ATP
B) It moves substances against their concentration gradient
C) It requires a carrier protein
D) It is the fastest mode of transport
C
What is the main difference between facilitated diffusion and active transport?
A) Active transport requires energy, while facilitated diffusion does not
B) Facilitated diffusion moves drugs against their concentration gradient
C) Active transport only occurs in the liver
D) Facilitated diffusion is non-saturable
A
The sodium-glucose co-transporter is an example of which type of transport?
A) Passive diffusion
B) Facilitated diffusion
C) Primary active transport
D) Secondary active transport
D
Which of the following transport mechanisms involves the engulfment of large molecules by the cell membrane?
A) Passive diffusion
B) Facilitated diffusion
C) Endocytosis
D) Active transport
C
Which of the following factors increases drug absorption?
A) High aqueous solubility
B) Large surface area of absorption site
C) Increased vascularity at the absorption site
D) All of the above
D
What is the role of P-glycoprotein (P-gp) in drug absorption?
A) It facilitates passive diffusion
B) It enhances drug absorption
C) It acts as an efflux transporter, reducing drug absorption
D) It transports only hydrophilic drugs
C
Which drug property leads to faster absorption through passive diffusion?
A) High molecular weight
B) High lipid solubility
C) High ionization in physiological pH
D) Large particle size
B
Which factor can slow down drug absorption from the gastrointestinal tract?
A) Increased gastric motility
B) Presence of food
C) High lipid solubility of the drug
D) Large surface area of the small intestine
B
How does the particle size of a solid drug affect its dissolution and absorption?
A) Smaller particles dissolve faster, leading to increased absorption
B) Larger particles dissolve faster than smaller particles
C) Particle size has no impact on drug absorption
D) Larger particles are absorbed more efficiently in the stomach
A
Which of the following is an example of a drug that is actively transported in the gut?
A) Aspirin
B) Levodopa
C) Diazepam
D) Paracetamol
B
Which route of drug administration bypasses the absorption process?
A) Oral
B) Sublingual
C) Intravenous
D) Rectal
C
What is the first-pass effect?
A) The initial breakdown of a drug before reaching the systemic circulation
B) The ability of a drug to cross the blood-brain barrier
C) The immediate renal excretion of a drug
D) The slow dissolution of a drug in the stomach
A
What is the primary determinant of the rate of drug absorption for oral medications?
A) Gastric pH
B) Drug solubility
C) Food in the stomach
D) All of the above
D
Which physiological factor significantly affects drug absorption from intramuscular and subcutaneous sites?
A) Vascularity of the site
B) Lipid solubility of the drug
C) Enzyme activity in the skin
D) The molecular weight of the drug
A
Which of the following is a characteristic of hydrophilic drugs?
A) They are rapidly absorbed through the lipid bilayer
B) Their absorption is limited by membrane permeability
C) They do not require dissolution before absorption
D) They are highly protein-bound
B
- A patient with severe diarrhea is prescribed an antibiotic. Which factor may reduce the drug’s absorption?
A) Increased gastric emptying
B) Increased drug solubility
C) Decreased gastric pH
D) Increased intestinal transit time
A
A weakly acidic drug with a pKa of 4.5 will be absorbed best in which part of the GI tract?
A) Stomach (pH 2)
B) Duodenum (pH 6)
C) Ileum (pH 7)
D) Colon (pH 8)
A
Which of the following factors affects passive diffusion of a drug?
A) Lipid solubility
B) Drug ionization
C) Concentration gradient
D) All of the above
D
Why do weak acids tend to be absorbed more in the stomach?
A) The stomach lining is highly permeable
B) Weak acids remain largely non-ionized in an acidic environment
C) The stomach has a large surface area for absorption
D) Acidic drugs actively bind to stomach enzymes
B
Which of the following best describes facilitated diffusion?
A) It moves substances from high to low concentration without energy
B) It moves substances against their concentration gradient
C) It involves engulfment of molecules by the cell membrane
D) It requires ATP to transport drugs across the membrane
A
What type of transport is used when a drug moves against its concentration gradient?
A) Passive diffusion
B) Facilitated diffusion
C) Active transport
D) Endocytosis
C
A drug with low aqueous solubility will likely have which of the following rate-determining steps for absorption?
A) Rate of dissolution
B) Rate of drug metabolism
C) Rate of elimination
D) Rate of diffusion through the bloodstream
A
What effect does increased vascularity at the absorption site have on drug absorption?
A) It slows down drug absorption
B) It increases drug absorption
C) It has no effect on absorption
D) It enhances first-pass metabolism
B
What is the main function of ATP-binding cassette (ABC) transporters in drug absorption?
A) They mediate passive diffusion of drugs
B) They act as efflux pumps to expel drugs from cells
C) They enhance lipid solubility of drugs
D) They neutralize weak acids
B
What is the role of the sodium-glucose transporter in drug absorption?
A) It facilitates glucose transport in the absence of sodium
B) It actively transports glucose into cells using energy
C) It is an example of symport active transport
D) It promotes passive diffusion of drugs
C
Which statement about oral absorption is TRUE?
A) Weak bases are absorbed primarily in the stomach
B) Acidic drugs are absorbed better in the stomach
C) Lipophilic drugs are poorly absorbed
D) The small intestine absorbs fewer drugs than the stomach
B
What effect does food in the stomach have on drug absorption?
A) It increases absorption of all drugs
B) It delays gastric emptying and slows absorption
C) It accelerates dissolution of drugs
D) It has no effect on drug absorption
B
A patient takes an acidic drug (pKa = 3.5) with an antacid that increases stomach pH. What will happen to drug absorption?
A) Absorption will increase
B) Absorption will decrease
C) Absorption will be unchanged
D) The drug will bypass first-pass metabolism
B
A lipophilic drug is administered orally. What is the most likely mechanism of its absorption?
A) Active transport
B) Endocytosis
C) Passive diffusion
D) Facilitated diffusion
C
A drug is formulated as a nanoparticle to improve absorption. What is the main reason for this formulation?
A) To increase drug metabolism
B) To decrease drug permeability
C) To increase drug dissolution rate
D) To enhance renal excretion
C
A weak acid drug is absorbed mainly in the stomach. What happens if the patient takes an antacid?
A) Drug absorption increases
B) The drug bypasses metabolism
C) The drug is excreted faster
D) Drug absorption decreases
D
A 70-year-old patient with reduced gastric acid production is given a basic drug. How will absorption be affected?
A) Decreased absorption in the stomach
B) Increased absorption in the stomach
C) No effect on absorption
D) Increased absorption in the colon
A
A patient takes a highly lipophilic drug with a high-fat meal. How will drug absorption be affected?
A) It will decrease significantly
B) The drug will become inactive
C) It will not be affected
D) It will be delayed but increased
D
A patient takes a drug that undergoes extensive first-pass metabolism. Which of the following is a possible consequence?
A) Increased bioavailability
B) Decreased oral bioavailability
C) Increased plasma drug concentration
D) Enhanced renal excretion
B
A patient receives an intravenous dose of a drug that is usually poorly absorbed orally. What is the advantage of this route?
A) Slower drug action
B) Increased drug degradation in plasma
C) Bypasses first-pass metabolism
D) Decreased drug concentration in the bloodstream
C
