1
Page | 1
Comprehensive NCLEX-RN
Psychopharmacology Q&A with Detailed
Rationales
, 2
1. A patient taking lithium for bipolar disorder presents with nausea, tremors, and
confusion. Which laboratory value would be most concerning?
A. Sodium 138 mEq/L
B. Lithium level 2.1 mEq/L
C. Potassium 4.0 mEq/L
Page | 2 D. Creatinine 0.9 mg/dL
✔Correct Answer: B. Lithium level 2.1 mEq/L
Rationale: A lithium level of 2.1 mEq/L indicates lithium toxicity. Therapeutic levels
typically range from 0.6 to 1.2 mEq/L. At levels above 2.0, patients can present with serious
symptoms like severe tremors, confusion, vomiting, and even seizures. It’s a medical
emergency. Sodium levels also influence lithium excretion; low sodium can increase lithium
retention. In this case, other values are within normal limits and less concerning. Immediate
management involves stopping lithium, providing IV fluids, and possibly dialysis if
symptoms are severe. Monitoring renal function is also crucial since lithium is renally
excreted.
2. Which drug class is contraindicated with MAO inhibitors due to the risk of
hypertensive crisis?
A. Selective serotonin reuptake inhibitors (SSRIs)
B. Benzodiazepines
C. Beta-blockers
D. Antipsychotics
✔Correct Answer: A. Selective serotonin reuptake inhibitors (SSRIs)
Rationale: SSRIs are contraindicated with monoamine oxidase inhibitors (MAOIs) due to
the high risk of serotonin syndrome and hypertensive crisis. Combining these can result in
dangerously high serotonin levels, leading to symptoms such as agitation, confusion,
hyperthermia, tachycardia, and potentially life-threatening outcomes. A washout period
(typically 14 days) is recommended when switching between SSRIs and MAOIs. The
combination of these two drugs interferes with serotonin metabolism and clearance.
Benzodiazepines, beta-blockers, and antipsychotics don’t carry the same direct risk of
hypertensive crisis in this context, though they may have other interactions.
3. A patient on warfarin reports the use of St. John’s Wort. What is the appropriate
response?
A. No change is needed
B. Decrease warfarin dose
C. Discontinue St. John’s Wort
D. Increase warfarin dose
✔Correct Answer: C. Discontinue St. John’s Wort
Rationale: St. John’s Wort is a known inducer of the cytochrome P450 enzymes, particularly
CYP3A4. This leads to increased metabolism of warfarin, significantly reducing its
anticoagulant effect and increasing the risk of thromboembolic events. Because of this
serious interaction, patients on warfarin should avoid St. John’s Wort. Monitoring INR levels
Page | 1
Comprehensive NCLEX-RN
Psychopharmacology Q&A with Detailed
Rationales
, 2
1. A patient taking lithium for bipolar disorder presents with nausea, tremors, and
confusion. Which laboratory value would be most concerning?
A. Sodium 138 mEq/L
B. Lithium level 2.1 mEq/L
C. Potassium 4.0 mEq/L
Page | 2 D. Creatinine 0.9 mg/dL
✔Correct Answer: B. Lithium level 2.1 mEq/L
Rationale: A lithium level of 2.1 mEq/L indicates lithium toxicity. Therapeutic levels
typically range from 0.6 to 1.2 mEq/L. At levels above 2.0, patients can present with serious
symptoms like severe tremors, confusion, vomiting, and even seizures. It’s a medical
emergency. Sodium levels also influence lithium excretion; low sodium can increase lithium
retention. In this case, other values are within normal limits and less concerning. Immediate
management involves stopping lithium, providing IV fluids, and possibly dialysis if
symptoms are severe. Monitoring renal function is also crucial since lithium is renally
excreted.
2. Which drug class is contraindicated with MAO inhibitors due to the risk of
hypertensive crisis?
A. Selective serotonin reuptake inhibitors (SSRIs)
B. Benzodiazepines
C. Beta-blockers
D. Antipsychotics
✔Correct Answer: A. Selective serotonin reuptake inhibitors (SSRIs)
Rationale: SSRIs are contraindicated with monoamine oxidase inhibitors (MAOIs) due to
the high risk of serotonin syndrome and hypertensive crisis. Combining these can result in
dangerously high serotonin levels, leading to symptoms such as agitation, confusion,
hyperthermia, tachycardia, and potentially life-threatening outcomes. A washout period
(typically 14 days) is recommended when switching between SSRIs and MAOIs. The
combination of these two drugs interferes with serotonin metabolism and clearance.
Benzodiazepines, beta-blockers, and antipsychotics don’t carry the same direct risk of
hypertensive crisis in this context, though they may have other interactions.
3. A patient on warfarin reports the use of St. John’s Wort. What is the appropriate
response?
A. No change is needed
B. Decrease warfarin dose
C. Discontinue St. John’s Wort
D. Increase warfarin dose
✔Correct Answer: C. Discontinue St. John’s Wort
Rationale: St. John’s Wort is a known inducer of the cytochrome P450 enzymes, particularly
CYP3A4. This leads to increased metabolism of warfarin, significantly reducing its
anticoagulant effect and increasing the risk of thromboembolic events. Because of this
serious interaction, patients on warfarin should avoid St. John’s Wort. Monitoring INR levels
