MCQ Quiz: Anesthetics

Anesthetics are a critical class of drugs that induce a reversible loss of sensation, allowing for painless surgical and medical procedures. Their use is a cornerstone of modern medicine. This quiz covers the fundamental types of anesthetics, including general and local agents, their mechanisms of action, and key clinical considerations.

1. What is the primary function of the Blood-Brain Barrier (BBB)?

• a. To increase blood flow to the brain.
• b. To protect the central nervous system (CNS) from toxins, pathogens, and circulating neurotransmitters.
• c. To facilitate the easy passage of all molecules from the blood into the brain.
• d. To produce cerebrospinal fluid (CSF).

Answer: b. To protect the central nervous system (CNS) from toxins, pathogens, and circulating neurotransmitters.

2. The BBB is primarily formed by which type of cells lining the brain’s capillaries?

• a. Neurons
• b. Astrocytes
• c. Microglia
• d. Endothelial cells

Answer: d. Endothelial cells

3. What type of cell-to-cell connection is a key feature of the BBB, severely restricting paracellular (between-cell) transport?

• a. Gap junctions
• b. Desmosomes
• c. Tight junctions
• d. Loose junctions

Answer: c. Tight junctions

4. A drug with which of the following characteristics is most likely to passively diffuse across the BBB?

• a. Large, water-soluble, and highly ionized.
• b. Small, lipid-soluble, and non-ionized.
• c. Highly bound to plasma proteins.
• d. A large peptide.

Answer: b. Small, lipid-soluble, and non-ionized.

5. Dopamine cannot be used to treat Parkinson’s disease because it cannot cross the BBB. However, its precursor, ______, can cross the BBB via an amino acid transporter.

• a. Carbidopa
• b. Serotonin
• c. Levodopa
• d. Norepinephrine

Answer: c. Levodopa

6. P-glycoprotein (P-gp) is an important protein at the BBB that functions as a(n):

• a. Influx transporter, pulling drugs into the brain.
• b. Efflux transporter, actively pumping drugs out of the brain back into the blood.
• c. Metabolic enzyme.
• d. Ion channel.

Answer: b. Efflux transporter, actively pumping drugs out of the brain back into the blood.

7. A drug that is a substrate for P-glycoprotein will likely have:

• a. High brain concentrations.
• b. Low brain concentrations.
• c. No difficulty crossing the BBB.
• d. A very long half-life in the CNS.

Answer: b. Low brain concentrations.

8. Which glial cells have “end-feet” that wrap around the brain capillaries and contribute to the induction and maintenance of the BBB?

• a. Oligodendrocytes
• b. Microglia
• c. Ependymal cells
• d. Astrocytes

Answer: d. Astrocytes

9. First-generation antihistamines like diphenhydramine cause drowsiness because they can cross the BBB. Second-generation antihistamines like loratadine are less sedating because they:

• a. Are more potent at the H1 receptor.
• b. Are less lipophilic and are substrates for P-glycoprotein, limiting their CNS penetration.
• c. Are administered at a much lower dose.
• d. Do not interact with histamine receptors.

Answer: b. Are less lipophilic and are substrates for P-glycoprotein, limiting their CNS penetration.

10. Which of the following is a method used to overcome the BBB for drug delivery?

• a. Designing highly lipophilic prodrugs.
• b. Conjugating a drug to a molecule that uses a specific transporter (e.g., the transferrin receptor).
• c. Temporarily disrupting the BBB with agents like mannitol.
• d. All of the above.

Answer: d. All of the above.

11. The “neurovascular unit” is a concept that describes the close interaction between brain endothelial cells, pericytes, astrocytes, and:

• a. Neurons
• b. Only other endothelial cells
• c. Red blood cells
• d. Cerebrospinal fluid

Answer: a. Neurons

12. Conditions such as meningitis, stroke, or multiple sclerosis can ____ the permeability of the BBB.

• a. decrease
• b. have no effect on
• c. increase
• d. repair

Answer: c. increase

13. Why is it important that neurotransmitters like norepinephrine and serotonin in the peripheral circulation do not cross the BBB?

• a. To prevent interference with the precisely controlled neurotransmission within the CNS.
• b. They do cross the BBB easily.
• c. Because they are not active in the brain.
• d. To ensure they reach peripheral tissues.

Answer: a. To prevent interference with the precisely controlled neurotransmission within the CNS.

14. A drug’s lipophilicity is often measured by its:

• a. Molecular weight
• b. pKa
• c. LogP value (octanol-water partition coefficient)
• d. Solubility in water

Answer: c. LogP value (octanol-water partition coefficient)

15. A highly protein-bound drug has less free concentration available to cross the BBB.

• a. True
• b. False

Answer: a. True

16. The brain lacks a traditional lymphatic system for drainage. This function is largely performed by the:

• a. Vascular system.
• b. Flow of cerebrospinal fluid (CSF).
• c. Microglia.
• d. Ventricles.

Answer: b. Flow of cerebrospinal fluid (CSF).

17. What is the role of pericytes in the BBB?

• a. They are immune cells of the brain.
• b. They are contractile cells that help regulate capillary diameter and contribute to BBB integrity.
• c. They produce myelin.
• d. They transmit nerve signals.

Answer: b. They are contractile cells that help regulate capillary diameter and contribute to BBB integrity.

18. Which of the following can freely pass through the BBB via simple diffusion?

• a. Glucose
• b. Amino acids
• c. Small, uncharged molecules like oxygen and carbon dioxide.
• d. Large proteins like albumin.

Answer: c. Small, uncharged molecules like oxygen and carbon dioxide.

19. How does glucose, the brain’s primary energy source, cross the BBB?

• a. Via simple diffusion.
• b. Via active transport.
• c. Via facilitated diffusion through specific GLUT1 transporters.
• d. It cannot cross the BBB.

Answer: c. Via facilitated diffusion through specific GLUT1 transporters.

20. A drug designed to inhibit P-glycoprotein might be used to:

• a. Decrease the CNS penetration of another drug.
• b. Increase the CNS penetration of another drug that is a P-gp substrate.
• c. Treat hypertension.
• d. Treat a bacterial infection.

Answer: b. Increase the CNS penetration of another drug that is a P-gp substrate.

21. The BBB is fully formed and impermeable at birth.

• a. True
• b. False

Answer: b. False

22. An area of the brain that lacks a BBB to allow for the detection of circulating hormones and toxins is the:

• a. Cerebellum
• b. Frontal cortex
• c. Chemoreceptor Trigger Zone (CTZ)
• d. Hippocampus

Answer: c. Chemoreceptor Trigger Zone (CTZ)

23. The lack of a BBB at the Chemoreceptor Trigger Zone is important for the mechanism of:

• a. Hunger and thirst.
• b. Vision.
• c. Nausea and vomiting.
• d. Motor control.

Answer: c. Nausea and vomiting.

24. Which of the following statements about the BBB is FALSE?

• a. It is a physical barrier.
• b. It is a metabolic barrier with enzymes that can break down drugs.
• c. It is a transport barrier with active efflux pumps.
• d. It has large gaps (fenestrations) between endothelial cells.

Answer: d. It has large gaps (fenestrations) between endothelial cells.

25. A pharmacist considers the BBB when:

• a. Choosing an antibiotic for a CNS infection like meningitis.
• b. Selecting an antihistamine for a patient who needs to avoid drowsiness.
• c. Understanding why levodopa is used instead of dopamine for Parkinson’s disease.
• d. All of the above.

Answer: d. All of the above.

26. A drug’s ability to cross the BBB is a key consideration in which field of study?

• a. Medicinal Chemistry and Pharmacology
• b. Pharmacoeconomics
• c. Pharmacy Law
• d. Pharmaceutics

Answer: a. Medicinal Chemistry and Pharmacology

27. A highly ionized (charged) molecule at physiological pH will have ____ difficulty crossing the BBB.

• a. no
• b. some
• c. significant
• d. It depends on the charge.

Answer: c. significant

28. What is the approximate molecular weight cutoff for easy passive diffusion across the BBB?

• a. 10,000 Daltons
• b. 5,000 Daltons
• c. 1,000 Daltons
• d. 400-500 Daltons

Answer: d. 400-500 Daltons

29. The concept of designing a lipophilic prodrug involves:

• a. Attaching a water-soluble group to the drug.
• b. Attaching a lipid-soluble group to a drug to help it cross the BBB, which is then cleaved to release the active drug.
• c. Making the drug larger.
• d. Making the drug an ion.

Answer: b. Attaching a lipid-soluble group to a drug to help it cross the BBB, which is then cleaved to release the active drug.

30. A key reason why many chemotherapy agents are not effective for brain tumors is:

• a. Brain tumors are not cancerous.
• b. The drugs cannot effectively cross the BBB to reach the tumor.
• c. The drugs are not potent enough.
• d. The drugs are too expensive.

Answer: b. The drugs cannot effectively cross the BBB to reach the tumor.

31. The BBB creates the unique challenge of designing drugs that are lipophilic enough to enter the brain but also have enough water solubility to be formulated and administered.

• a. True
• b. False

Answer: a. True

32. Which of the following is NOT a component of the neurovascular unit?

• a. Endothelial cells
• b. Pericytes
• c. Astrocytes
• d. Red blood cells

Answer: d. Red blood cells

33. The brain is considered an “immunologically privileged” site, in part due to the BBB.

• a. True
• b. False

Answer: a. True

34. Loperamide is an opioid agonist that does not cause CNS effects at normal doses because:

• a. It does not bind to opioid receptors.
• b. It is a potent substrate for the P-glycoprotein efflux pump at the BBB.
• c. It is rapidly metabolized in the blood.
• d. It is not an opioid.

Answer: b. It is a potent substrate for the P-glycoprotein efflux pump at the BBB.

35. A high dose of a drug that is a P-gp substrate can sometimes overwhelm the efflux pump, leading to increased CNS penetration and side effects.

• a. True
• b. False

Answer: a. True

36. Inflammation of the brain and its surrounding membranes (meningitis) can make the BBB:

• a. More selective.
• b. “Leaky” or more permeable.
• c. Stronger.
• d. Thicker.

Answer: b. “Leaky” or more permeable.

37. How does the “leakiness” of the BBB in meningitis affect drug therapy?

• a. It makes it harder for all drugs to enter the CNS.
• b. It allows some antibiotics that normally cross poorly (like penicillin) to enter the CNS more effectively.
• c. It has no effect on drug therapy.
• d. It requires lower doses of all antibiotics.

Answer: b. It allows some antibiotics that normally cross poorly (like penicillin) to enter the CNS more effectively.

38. The blood-CSF barrier, located in the choroid plexus, is another barrier protecting the brain.

• a. True
• b. False

Answer: a. True

39. A drug with a high LogP value is:

• a. Hydrophilic
• b. Lipophilic
• c. A large molecule
• d. A small molecule

Answer: b. Lipophilic

40. The development of drugs that target brain disorders is one of the most challenging areas of medicinal chemistry due to the BBB.

• a. True
• b. False

Answer: a. True

41. Which of the following properties would be desirable for a new CNS-acting drug?

• a. Small molecular weight, optimal lipophilicity, not a P-gp substrate.
• b. Large molecular weight, hydrophilic, a P-gp substrate.
• c. High protein binding, ionized at physiological pH.
• d. Large size, charged, water-soluble.

Answer: a. Small molecular weight, optimal lipophilicity, not a P-gp substrate.

42. The “Trojan horse” strategy for drug delivery to the brain involves:

• a. Disrupting the BBB.
• b. Using a lipophilic prodrug.
• c. Attaching the drug to a molecule that can use a specific receptor-mediated transport system to get across the BBB.
• d. Injecting the drug directly into the brain.

Answer: c. Attaching the drug to a molecule that can use a specific receptor-mediated transport system to get across the BBB.

43. A pharmacist’s understanding of the BBB is crucial for:

• a. Predicting CNS side effects of medications.
• b. Counseling patients on why some drugs cause drowsiness and others do not.
• c. Understanding why certain drugs are chosen for CNS infections.
• d. All of the above.

Answer: d. All of the above.

44. Active transport across the BBB requires:

• a. A concentration gradient.
• b. Energy (ATP) and a carrier protein.
• c. The drug to be lipophilic.
• d. The drug to be small.

Answer: b. Energy (ATP) and a carrier protein.

45. Which of the following is NOT a function of the BBB?

• a. Regulating the CNS microenvironment.
• b. Protecting the brain from toxins.
• c. Transmitting nerve impulses.
• d. Transporting essential nutrients into the brain.

Answer: c. Transmitting nerve impulses.

46. The presence of pericytes is a key difference between brain capillaries and peripheral capillaries.

• a. True
• b. False

Answer: a. True

47. The total surface area of the human blood-brain barrier is estimated to be:

• a. The size of a postage stamp.
• b. The size of a dinner plate.
• c. The size of a tennis court.
• d. The size of a football field.

Answer: c. The size of a tennis court.

48. Why is carbidopa given with levodopa?

• a. It is a decarboxylase inhibitor that does not cross the BBB, so it prevents levodopa from being converted to dopamine in the periphery.
• b. It helps levodopa cross the BBB.
• c. It is another dopamine precursor.
• d. It treats the motor symptoms of Parkinson’s.

Answer: a. It is a decarboxylase inhibitor that does not cross the BBB, so it prevents levodopa from being converted to dopamine in the periphery.

49. The overall effect of the BBB is to create a highly controlled and stable:

• a. Peripheral nervous system environment.
• b. Central nervous system microenvironment.
• c. Cardiovascular system.
• d. Gastrointestinal system.

Answer: b. Central nervous system microenvironment.

50. The ultimate reason for a pharmacist to understand the BBB is to:

• a. Better predict and manage the central effects and side effects of medications.
• b. Design new CNS drugs.
• c. Perform brain surgery.
• d. Memorize a list of lipophilic drugs.

Answer: a. Better predict and manage the central effects and side effects of medications.