MCQ Quiz: Pharmacology of Mood Stabilizing Drugs

Welcome to this focused MCQ quiz on the pharmacology of mood-stabilizing drugs, a vital component of the PharmD curriculum. Mood stabilizers are the cornerstone of treatment for bipolar disorder and other mood-related conditions. This quiz will challenge your understanding of the intricate mechanisms of action, pharmacokinetics, and pharmacodynamics of key agents like lithium, valproate, lamotrigine, and atypical antipsychotics. A strong grasp of this topic is essential for safe and effective medication management, including therapeutic monitoring and handling of adverse effects. Let’s test your knowledge on these complex but crucial medications.

1. The precise mechanism of action for lithium is not fully understood, but it is believed to modulate intracellular signaling pathways by inhibiting which enzyme?

• A. Monoamine Oxidase (MAO)
• B. Glycogen Synthase Kinase-3 (GSK-3)
• C. Catechol-O-methyltransferase (COMT)
• D. Acetylcholinesterase

Answer: B. Glycogen Synthase Kinase-3 (GSK-3)

2. From a pharmacokinetic standpoint, how is lithium primarily eliminated from the body?

• A. Through hepatic metabolism via CYP3A4
• B. Almost exclusively through renal excretion
• C. Through biliary excretion into the feces
• D. Through pulmonary exhalation

Answer: B. Almost exclusively through renal excretion

3. The co-administration of which class of drugs can significantly increase lithium serum concentrations by reducing its renal clearance?

• A. Beta-blockers
• B. Proton pump inhibitors
• C. Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)
• D. Statins

Answer: C. Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

4. Valproic acid (divalproex) is thought to exert its mood-stabilizing effects in part by increasing the levels of which inhibitory neurotransmitter?

• A. Serotonin
• B. Dopamine
• C. Gamma-aminobutyric acid (GABA)
• D. Glutamate

Answer: C. Gamma-aminobutyric acid (GABA)

5. Lamotrigine’s primary mechanism of action, which makes it effective for bipolar depression, involves the blockade of:

• A. Dopamine D2 receptors
• B. Serotonin transporters (SERT)
• C. Voltage-gated sodium channels
• D. Muscarinic acetylcholine receptors

Answer: C. Voltage-gated sodium channels

6. A slow dose titration is required when initiating lamotrigine to reduce the risk of which potentially life-threatening dermatological reaction?

• A. Urticaria
• B. Psoriasis
• C. Alopecia
• D. Stevens-Johnson Syndrome (SJS)

Answer: D. Stevens-Johnson Syndrome (SJS)

7. Carbamazepine is a mood stabilizer that exhibits a unique pharmacokinetic property of auto-induction. What does this mean?

• A. It inhibits its own metabolism, leading to increased drug levels over time.
• B. It induces its own metabolism, primarily via CYP3A4, leading to decreased drug levels over time.
• C. It is eliminated only through the kidneys without being metabolized.
• D. It directly induces the synthesis of neurotransmitters.

Answer: B. It induces its own metabolism, primarily via CYP3A4, leading to decreased drug levels over time.

8. Many atypical antipsychotics, such as olanzapine and quetiapine, are used as mood stabilizers. Their mechanism involves a combination of antagonism at which two key receptors?

• A. Serotonin 5-HT1A and Histamine H1
• B. Dopamine D2 and Serotonin 5-HT2A
• C. Alpha-1 adrenergic and Muscarinic M1
• D. GABA-A and NMDA

Answer: B. Dopamine D2 and Serotonin 5-HT2A

9. What is the therapeutic serum concentration range for lithium in the treatment of acute mania?

• A. 0.2 – 0.6 mEq/L
• B. 0.8 – 1.2 mEq/L
• C. 2.0 – 2.5 mEq/L
• D. > 3.0 mEq/L

Answer: B. 0.8 – 1.2 mEq/L

10. A patient taking lithium presents with nausea, vomiting, coarse tremor, and confusion. These are signs of lithium toxicity, which is exacerbated by what condition?

• A. Hypernatremia (high sodium)
• B. Hypokalemia (low potassium)
• C. Hyponatremia (low sodium) and dehydration
• D. Hypercalcemia (high calcium)

Answer: C. Hyponatremia (low sodium) and dehydration

11. Valproic acid is a potent inhibitor of several UGT and CYP enzymes. Its co-administration can significantly increase the concentration of which other mood stabilizer?

• A. Lithium
• B. Lamotrigine
• C. Topiramate
• D. Aripiprazole

Answer: B. Lamotrigine

12. The primary pharmacological action of atypical antipsychotics that helps mitigate the risk of extrapyramidal symptoms (EPS) compared to typical antipsychotics is:

• A. More potent D2 receptor blockade.
• B. Potent 5-HT2A receptor blockade, which increases dopamine release in the nigrostriatal pathway.
• C. Blockade of histamine H1 receptors.
• D. Inhibition of the norepinephrine transporter.

Answer: B. Potent 5-HT2A receptor blockade, which increases dopamine release in the nigrostriatal pathway.

13. Which of the following mood stabilizers has a black box warning for teratogenicity, specifically an increased risk of neural tube defects like spina bifida?

• A. Lithium
• B. Lamotrigine
• C. Valproic acid
• D. Oxcarbazepine

Answer: C. Valproic acid

14. The metabolic side effects of atypical antipsychotics, such as weight gain and hyperglycemia, are strongly associated with their antagonist activity at which receptors?

• A. Dopamine D2 and Serotonin 5-HT1A
• B. Muscarinic M3 and Nicotinic
• C. Histamine H1 and Serotonin 5-HT2C
• D. Alpha-2 adrenergic and Beta-1

Answer: C. Histamine H1 and Serotonin 5-HT2C

15. Carbamazepine is a potent inducer of CYP3A4. What effect would this have on a CYP3A4 substrate, such as an oral contraceptive?

• A. It would increase the concentration and efficacy of the contraceptive.
• B. It would have no effect on the contraceptive.
• C. It would decrease the concentration of the contraceptive, potentially leading to therapeutic failure.
• D. It would change the contraceptive’s mechanism of action.

Answer: C. It would decrease the concentration of the contraceptive, potentially leading to therapeutic failure.

16. While not a first-line mood stabilizer, which anticonvulsant is sometimes used off-label and is known for causing weight loss and cognitive side effects (“dopamax”)?

• A. Gabapentin
• B. Levetiracetam
• C. Topiramate
• D. Pregabalin

Answer: C. Topiramate

17. What is the pharmacological rationale for using a mood stabilizer in conjunction with an antidepressant to treat bipolar depression?

• A. To increase the metabolism of the antidepressant.
• B. To prevent the antidepressant from inducing a switch into mania or hypomania.
• C. To treat the anticholinergic side effects of the antidepressant.
• D. This combination is always contraindicated.

Answer: B. To prevent the antidepressant from inducing a switch into mania or hypomania.

18. Aripiprazole (Abilify) has a unique mechanism of action as a mood stabilizer, which is best described as:

• A. Pure D2 receptor antagonism.
• B. Partial agonism at the D2 and 5-HT1A receptors.
• C. Irreversible inhibition of MAO.
• D. Selective serotonin reuptake inhibition.

Answer: B. Partial agonism at the D2 and 5-HT1A receptors.

19. Baseline and periodic monitoring of which of the following is essential for a patient on long-term lithium therapy?

• A. Serum creatinine (renal function) and TSH (thyroid function)
• B. Liver function tests and CBC
• C. Serum amylase and lipase
• D. Echocardiogram and ECG

Answer: A. Serum creatinine (renal function) and TSH (thyroid function)

20. The pharmacodynamic profile of quetiapine, especially at lower doses, is dominated by potent antagonism of which receptor, leading to its strong sedative properties?

• A. Dopamine D2 receptor
• B. Serotonin 5-HT2A receptor
• C. Histamine H1 receptor
• D. Alpha-1 adrenergic receptor

Answer: C. Histamine H1 receptor

21. Why is therapeutic drug monitoring (TDM) crucial for carbamazepine?

• A. Because it has a very long half-life.
• B. Because of its auto-induction property, which causes its levels to change over the first few weeks of therapy.
• C. Because it is not metabolized by the liver.
• D. Because it has no known side effects.

Answer: B. Because of its auto-induction property, which causes its levels to change over the first few weeks of therapy.

22. Which anticonvulsant mood stabilizer is generally considered to be more effective for the maintenance treatment of bipolar depression rather than for acute mania?

• A. Valproic acid
• B. Carbamazepine
• C. Lamotrigine
• D. Lithium

Answer: C. Lamotrigine

23. The risk of hyperprolactinemia, leading to side effects like galactorrhea and amenorrhea, is highest with atypical antipsychotics that have potent antagonist activity at which receptor?

• A. Serotonin 5-HT2A
• B. Histamine H1
• C. Dopamine D2
• D. Muscarinic M1

Answer: C. Dopamine D2

24. In terms of pharmacokinetics, valproic acid is highly bound to which plasma protein?

• A. Hemoglobin
• B. Alpha-1 acid glycoprotein
• C. Albumin
• D. Transferrin

Answer: C. Albumin

25. Which of the following is a key counseling point regarding diet for a patient taking lithium?

• A. They must strictly avoid all tyramine-containing foods.
• B. They should dramatically increase their caffeine intake.
• C. They must maintain a consistent intake of salt and fluids to keep lithium levels stable.
• D. They should follow a high-protein, low-carbohydrate diet.

Answer: C. They must maintain a consistent intake of salt and fluids to keep lithium levels stable.

26. The term “steady state” in pharmacokinetics, which is critical for interpreting mood stabilizer levels, is typically reached after how many half-lives?

• A. 1-2 half-lives
• B. 2-3 half-lives
• C. 4-5 half-lives
• D. More than 10 half-lives

Answer: C. 4-5 half-lives

27. What is the primary pharmacologic reason that an SSRI is not recommended as monotherapy for bipolar disorder?

• A. It is ineffective for treating depressive symptoms.
• B. It carries a high risk of inducing a switch to mania or causing rapid cycling.
• C. It has too many drug interactions with mood stabilizers.
• D. It is not absorbed well in patients with bipolar disorder.

Answer: B. It carries a high risk of inducing a switch to mania or causing rapid cycling.

28. Which atypical antipsychotic has a lower risk of metabolic side effects but a higher risk of akathisia?

• A. Olanzapine
• B. Quetiapine
• C. Clozapine
• D. Aripiprazole

Answer: D. Aripiprazole

29. What is the pharmacodynamic basis for the orthostatic hypotension sometimes seen with atypical antipsychotics like risperidone and quetiapine?

• A. Blockade of histamine H1 receptors
• B. Blockade of alpha-1 adrenergic receptors
• C. Blockade of dopamine D2 receptors
• D. Blockade of muscarinic M1 receptors

Answer: B. Blockade of alpha-1 adrenergic receptors

30. Which of the following is a long-term potential adverse effect of lithium on the kidneys?

• A. Acute tubular necrosis
• B. Nephrogenic diabetes insipidus
• C. Glomerulonephritis
• D. Renal cell carcinoma

Answer: B. Nephrogenic diabetes insipidus

31. The mechanism of action for oxcarbazepine is similar to carbamazepine, primarily involving:

• A. Enhancement of GABAergic transmission.
• B. Blockade of voltage-gated sodium channels.
• C. Antagonism of glutamate receptors.
• D. Inhibition of T-type calcium channels.

Answer: B. Blockade of voltage-gated sodium channels.

32. A “loading dose” may be used when initiating a drug like valproic acid in an acute setting. What is the pharmacokinetic rationale for a loading dose?

• A. To decrease the time it takes to reach therapeutic steady-state concentrations.
• B. To test for allergic reactions.
• C. To induce metabolic enzymes.
• D. To saturate plasma protein binding.

Answer: A. To decrease the time it takes to reach therapeutic steady-state concentrations.

33. From a pharmacodynamic perspective, the “dissociation constant” (Kd) for a drug at a receptor is a measure of:

• A. The drug’s efficacy.
• B. The drug’s half-life.
• C. The drug’s affinity for the receptor.
• D. The drug’s rate of metabolism.

Answer: C. The drug’s affinity for the receptor.

34. Valproic acid’s inhibition of histone deacetylase (HDAC) is an example of which type of pharmacological mechanism?

• A. Direct receptor antagonism
• B. Modulation of gene expression through epigenetic changes
• C. Ion channel blockade
• D. Enzyme induction

Answer: B. Modulation of gene expression through epigenetic changes

35. If a patient taking carbamazepine is started on a potent CYP3A4 inhibitor like ketoconazole, what is the likely pharmacokinetic outcome?

• A. The carbamazepine level will decrease, risking treatment failure.
• B. The carbamazepine level will increase, risking toxicity.
• C. There will be no change in carbamazepine levels.
• D. The ketoconazole level will decrease.

Answer: B. The carbamazepine level will increase, risking toxicity.

36. The pharmacology of lurasidone (Latuda) as a treatment for bipolar depression involves D2/5-HT2A antagonism as well as high affinity for which other serotonin receptor?

• A. 5-HT1A (as a partial agonist)
• B. 5-HT2C (as an antagonist)
• C. 5-HT3 (as an antagonist)
• D. 5-HT7 (as an antagonist)

Answer: D. 5-HT7 (as an antagonist)

37. The term “pharmacokinetics” describes which of the following processes?

• A. The mechanism by which a drug produces its effect.
• B. The study of how genes affect a person’s response to drugs.
• C. The movement of a drug into, through, and out of the body (ADME).
• D. The interaction of a drug with its receptor.

Answer: C. The movement of a drug into, through, and out of the body (ADME).

38. Which mood stabilizer is associated with a risk of agranulocytosis and requires strict blood monitoring if used (though it’s more common for schizophrenia)?

• A. Lithium
• B. Olanzapine
• C. Clozapine
• D. Risperidone

Answer: C. Clozapine

39. The sedation associated with olanzapine is primarily due to its strong antagonism of which receptor?

• A. Dopamine D1
• B. Serotonin 5-HT3
• C. Histamine H1
• D. Nicotinic

Answer: C. Histamine H1

40. Why is routine pregnancy testing recommended for female patients of childbearing potential who are taking valproic acid?

• A. It can cause false positive pregnancy tests.
• B. It is a known major teratogen.
• C. It can induce early labor.
• D. It increases fertility.

Answer: B. It is a known major teratogen.

41. The volume of distribution (Vd) of lithium is approximately equal to total body water. What does this pharmacokinetic parameter suggest?

• A. The drug is highly bound to plasma proteins.
• B. The drug does not leave the bloodstream.
• C. The drug distributes widely throughout the body into both intracellular and extracellular fluid.
• D. The drug is extensively sequestered in fat tissue.

Answer: C. The drug distributes widely throughout the body into both intracellular and extracellular fluid.

42. Which mood stabilizer has a mechanism that is thought to decrease central glutamatergic activity, which may contribute to its efficacy in bipolar depression?

• A. Valproic acid
• B. Lithium
• C. Lamotrigine
• D. Carbamazepine

Answer: C. Lamotrigine

43. As a partial agonist, aripiprazole can act as a functional antagonist in a hyperdopaminergic state (like mania) and a functional agonist in a hypodopaminergic state. This pharmacological concept is known as:

• A. Tachyphylaxis
• B. Intrinsic activity
• C. Dopamine system stabilization
• D. Allosteric modulation

Answer: C. Dopamine system stabilization

44. A patient taking valproic acid should be monitored for which of the following hematological adverse effects?

• A. Polycythemia
• B. Thrombocytosis
• C. Thrombocytopenia
• D. Leukocytosis

Answer: C. Thrombocytopenia

45. The half-life of a drug is a pharmacokinetic parameter that determines:

• A. The maximum effect of the drug.
• B. The time it takes for the drug concentration to decrease by 50%.
• C. The drug’s affinity for its receptor.
• D. The drug’s oral bioavailability.

Answer: B. The time it takes for the drug concentration to decrease by 50%.

46. Which two mood stabilizing medications are well-known for causing weight gain as a significant side effect?

• A. Lamotrigine and Topiramate
• B. Lithium and Valproic Acid
• C. Carbamazepine and Aripiprazole
• D. Ziprasidone and Lurasidone

Answer: B. Lithium and Valproic Acid

47. The “loose” binding and rapid dissociation from the D2 receptor is a pharmacodynamic property of which atypical antipsychotic, thought to contribute to its low risk of EPS?

• A. Haloperidol
• B. Risperidone
• C. Quetiapine
• D. Olanzapine

Answer: C. Quetiapine

48. What is the pharmacological basis for a drug interaction between carbamazepine and lamotrigine?

• A. Carbamazepine inhibits the metabolism of lamotrigine.
• B. Carbamazepine induces the metabolism of lamotrigine, decreasing its concentration.
• C. Both drugs compete for the same plasma protein binding sites.
• D. Lamotrigine inhibits the metabolism of carbamazepine.

Answer: B. Carbamazepine induces the metabolism of lamotrigine, decreasing its concentration.

49. Polyuria (excessive urination) and polydipsia (excessive thirst) are common side effects of lithium therapy due to its effect on:

• A. The liver’s ability to metabolize fluids.
• B. The kidneys’ response to antidiuretic hormone (ADH).
• C. The thirst center in the hypothalamus.
• D. The release of aldosterone.

Answer: B. The kidneys’ response to antidiuretic hormone (ADH).

50. What is a key pharmacological principle to remember when dosing lamotrigine in a patient who is also taking valproic acid?

• A. The lamotrigine dose should be higher than usual.
• B. The lamotrigine dose must be initiated at a lower level and titrated more slowly due to valproate’s inhibition of its metabolism.
• C. The two drugs cannot be used together.
• D. The valproic acid dose should be cut in half.

Answer: B. The lamotrigine dose must be initiated at a lower level and titrated more slowly due to valproate’s inhibition of its metabolism.