Psychiatry

Antidepressants

Choose antidepressants by clinical goals and adverse effects, recognize toxic syndromes, and plan safe monitoring, pregnancy care, tapering, and switches.

An antidepressant choice is a prediction about benefit, tolerability, and safety in one person. Two patients with the same depression score may need different treatment because one has painful neuropathy and another has a history of bulimia. Start with the illness being treated and the adverse effect the patient can least afford, rather than treating a drug class as a list of interchangeable names.

Connect the target to the clinical effect

At a monoamine synapse, released transmitter acts on receptors and is then cleared or metabolized. SERT retrieves serotonin, NET retrieves norepinephrine, and DAT retrieves dopamine. Inhibiting a transporter reduces reuptake; it does not increase the transporter's ability to clear transmitter. MAO inhibition reduces monoamine metabolism. Presynaptic alpha-2 blockade reduces an inhibitory feedback signal. These mechanisms help organize drugs, but they do not prove that depression is simply a measured shortage of one transmitter.

Clearance at the nerve ending

SSRIs inhibit SERT. SNRIs inhibit SERT and NET. Bupropion inhibits norepinephrine and dopamine reuptake. These actions differ from direct receptor activation.

Metabolism inside cells

MAO inhibitors limit monoamine breakdown. Interactions with dietary tyramine and other drugs depend on the particular formulation and dose.

Receptor regulation

Mirtazapine blocks alpha-2 receptors and selected serotonin receptors. Histamine H1 antagonism helps explain its sedation and appetite effects.

Transporter effects occur before the full clinical response. Early nausea does not mean an SSRI has already delivered its maximum antidepressant benefit. Follow symptoms, function, adherence, and adverse effects over time. Improvement may emerge over several weeks, but a rule to do nothing until week eight is inappropriate when adverse effects, suicidality, or no response require reassessment. [1]

The monoamine framework is also incomplete. Intranasal esketamine acts as an NMDA receptor antagonist. Its US treatment-resistant depression indication now allows monotherapy or combination with an oral antidepressant. Administration still requires supervised monitoring under its restricted program, including at least two hours of observation. The indication does not establish that it prevents suicide, and improvement after a dose does not cancel a need for hospitalization. [18]

Try it here · Checkpoint 1 of 3

Make your prediction before reading the choices. A first attempt is just a starting point.

Case 27

Show answer and explanations

A. Dopamine D2 antagonism. (Why this does not fit)
D2 blockade is associated with antipsychotic motor and prolactin effects, not the characteristic TCA antimuscarinic and orthostatic pattern.
B. Antimuscarinic and alpha-1 receptor blockade, with possible additional sedating H1 effects. (Best answer)
These off-target receptor actions explain retention, dry or blurred visual symptoms, orthostasis, and sedation.
C. Selective SERT inhibition with no receptor effects. (Why this does not fit)
That description omits the TCA actions responsible for this adverse-effect pattern.
D. MAO inhibition alone. (Why this does not fit)
Amitriptyline is not an MAOI, and its anticholinergic burden better fits the findings.

Takeaway: TCA tolerability reflects several targets beyond monoamine reuptake.

Case sources: [19]

Try another question from this subject

A 46-year-old man comes for follow-up of depressed mood and insomnia. He says that yesterday he purchased a handgun and ammunition and wrote letters to his children because he plans to shoot himself tonight. He has been drinking heavily but is not currently intoxicated. He refuses permission to contact family and asks for a sleeping medication. He is calm, oriented, and has no hallucinations.

Which of the following is the most appropriate next step?

Choose an answer before revealing the reasoning.

Get one of these every morning · Practice more in the QBank

Choose among reuptake inhibitors

Fluoxetine, sertraline, paroxetine, citalopram, escitalopram, and fluvoxamine are SSRIs. Their shared serotonergic effects can produce nausea, diarrhea, sexual dysfunction, and early activation. Platelet serotonin effects can increase bleeding risk, especially with NSAIDs or anticoagulants. SIADH and hyponatremia are particularly relevant in susceptible older adults. A class effect does not mean equal interaction profiles, half-lives, approved indications, or dosing rules. [2]

Fluoxetine and its active metabolite persist for weeks, which reduces abrupt concentration changes but complicates interactions and switching. Fluoxetine also has specific bulimia nervosa and OCD indications; an indication belongs to the individual product, not automatically to every SSRI. Paroxetine is associated with more troublesome withdrawal and greater anticholinergic burden than many other SSRIs. Sertraline does not require dose adjustment solely for renal impairment, although liver disease changes its dosing.

Citalopram has dose-dependent QT concerns; the maximum recommended daily dose is 20 mg above age 60, in hepatic impairment, and in certain CYP2C19-related circumstances. Persistent QTc above 500 ms warrants discontinuation under its label. [9] [10] [2] [1] [23]

Venlafaxine, desvenlafaxine, and duloxetine are SNRIs. Noradrenergic effects can contribute to sweating, increased pulse, and increased blood pressure. Monitor blood pressure with venlafaxine and reconsider treatment when increases are sustained. Duloxetine can address depression with diabetic peripheral neuropathic pain, fibromyalgia, or chronic musculoskeletal pain. Its US labeling advises avoiding use in severe renal impairment with GFR below 30 mL/min and in chronic liver disease or cirrhosis. [3] [4]

Milnacipran belongs to the SNRI family but its US product is indicated for fibromyalgia, not major depressive disorder. Levomilnacipran is a different drug; do not transfer indications between similar names. The presence of pain can favor a drug with a relevant indication, but kidney function, blood pressure, interactions, and the patient's preferences still determine whether it is a reasonable choice. [17]

TCAs include amitriptyline, nortriptyline, imipramine, desipramine, and clomipramine. Their serotonin and norepinephrine reuptake effects coexist with varying antimuscarinic, histamine H1, and alpha-1 blockade. Dry mouth, constipation, urinary retention, sedation, and orthostasis follow from these additional actions. Secondary amines such as nortriptyline often have a lower anticholinergic burden than amitriptyline, but are not free of it. Clomipramine's role in OCD does not erase its cardiac and anticholinergic risks. [19] [26]

Use distinctive adverse effects to individualize care

Benefits and liabilities belong in the same decision
Drug	Potential fit	Reason to reconsider
Bupropion	Depression when sexual adverse effects or smoking cessation are priorities	Seizure disorder, current or prior anorexia or bulimia, or abrupt withdrawal from selected sedatives
Mirtazapine	Depression with insomnia and poor appetite	Weight gain, daytime somnolence, or a high fall burden
Trazodone	Antidepressant treatment with sedating properties	Orthostasis, daytime impairment, or priapism
Vortioxetine	An alternative for major depression after individualized review	Nausea, serotonergic interactions, and possible sexual dysfunction

Bupropion has relatively little direct serotonergic activity and generally fewer sexual adverse effects than SSRIs. [21] Its seizure risk is dose-related, and an eating-disorder history remains relevant even after purging stops. Appropriate bupropion formulations are used for smoking cessation; off-label use for adult ADHD has trial support but does not make it an immediate stimulant substitute. [22] It can worsen insomnia or increase blood pressure and is not harmless in overdose. [5]

Mirtazapine combines alpha-2 antagonism with 5-HT2, 5-HT3, and H1 blockade. Appetite increase and sedation can be useful when those symptoms are prominent, but should be discussed as tradeoffs. It is not a guaranteed weight-restoration treatment, and a simplistic promise that a higher dose always eliminates sedation is unreliable. Compared with a strongly anticholinergic TCA, it may be a more reasonable option in a patient with urinary symptoms, while still requiring monitoring. [6]

Trazodone has serotonin reuptake inhibition and 5-HT2 antagonism, with H1 and alpha-1 effects contributing to sedation and orthostasis. Low-dose use for insomnia is off-label and is not equivalent to an adequate antidepressant regimen. A prolonged erection, particularly beyond four hours, requires emergency assessment. Vortioxetine inhibits SERT and modulates several serotonin receptors. It can still cause sexual dysfunction; neither its receptor profile nor improvement in depression establishes treatment of an independent cognitive disorder. [7] [8]

Ask about sexual function before and after treatment. Consider depression itself, relationship factors, endocrine or vascular illness, and other drugs. Options may include cautious dose adjustment, switching to a drug with a different adverse-effect profile, or a targeted adjunct. Sildenafil has randomized evidence in men with remitted depression and SRI-associated sexual dysfunction, subject to its own contraindications. Choose an adjunct for the specific symptom, evidence and patient contraindications; no option is guaranteed to work. [16]

Distinguish three dangerous medication patterns

Serotonin toxicity commonly follows adding, increasing, or combining serotonergic agents. Tramadol, linezolid, and IV methylene blue are relevant interaction checks. Agitation with diaphoresis, diarrhea, hyperreflexia, and clonus after such an exposure should prompt urgent cessation of implicated agents and supportive medical treatment. Neuromuscular excitation helps distinguish this pattern from uncomplicated anxiety. Neuroleptic malignant syndrome more often follows dopamine blockade or withdrawal of dopaminergic treatment and features generalized rigidity; neither syndrome should be diagnosed by fever alone. [2] [3]

Supportive treatment remains central in serotonin toxicity; severe cases may need sedation and airway support. Serotonin antagonists such as cyproheptadine have been used as adjuncts under specialist direction. An adjunct must not delay resuscitation or treatment of dangerous hyperthermia. [25]

TCAs can block fast cardiac sodium channels in overdose, causing conduction delay, wide QRS complexes, hypotension, ventricular dysrhythmias, and seizures. Sodium bicarbonate provides sodium loading and alkalinization; it does not pull sodium away from a channel. AHA recommends bicarbonate for life-threatening TCA cardiotoxicity. For persistent wide-complex dysrhythmia despite appropriate initial treatment, a class Ib agent such as lidocaine can be considered with toxicology expertise. A blanket statement that lidocaine is forbidden is incorrect. [13] [19]

Phenelzine and tranylcypromine inhibit MAO and can cause a dangerous pressor response to excessive tyramine or sympathomimetic exposure. Severe headache and hypertension after a high-tyramine meal require emergency evaluation and controlled treatment, potentially including a short-acting agent such as phentolamine. This is a different mechanism from sodium-channel toxicity. The selegiline patch has dose-specific dietary rules. At 6 mg per 24 hours a modified tyramine diet is not required by its label, whereas 9 and 12 mg per 24 hours require restrictions that continue for two weeks after stopping or reducing those doses. [11] [12]

Hyponatremia is another emergency pathway. Confusion or a seizure after starting an SSRI warrants sodium measurement and assessment of the cause. Severe or moderately severe symptoms attributable to hyponatremia require urgent monitored hypertonic saline treatment, irrespective of an arbitrary sodium cutoff such as 120 mmol/L. Stop the suspected causative drug as appropriate, prevent overly rapid correction, and distinguish SIADH from hypovolemia before choosing ongoing fluid treatment. [14]

Try it here · Checkpoint 2 of 3

Make your prediction before reading the choices. A first attempt is just a starting point.

Case 14

Show answer and explanations

A. Give procainamide for the persistent wide-complex dysrhythmia. (Why this does not fit)
Class Ia agents can aggravate the sodium-channel conduction toxicity.
B. Give propranolol to slow the ventricular rhythm. (Why this does not fit)
Beta blockade is not the recommended rescue here and can worsen cardiovascular compromise.
C. Consider lidocaine in this refractory setting. (Best answer)
A class Ib antiarrhythmic can be considered for persistent dysrhythmia from sodium-channel-blocker poisoning after initial treatment.
D. Use magnesium as the only next antiarrhythmic despite no torsades or prolonged-QT pattern. (Why this does not fit)
Magnesium is not the targeted rescue for this refractory TCA sodium-channel dysrhythmia; rhythm-specific toxicology management is needed.

Takeaway: Drug-class names alone do not determine an antidotal or rescue role.

Case sources: [13]

Plan the first month and the last dose

Before prescribing, assess suicide risk, prior treatment response, bipolar symptoms, substance use, interactions, and relevant medical illness. Review an antidepressant usually within two weeks, and within one week for a person aged 18 to 25 or when suicide risk is a particular concern. Early intense restlessness, new suicidal thoughts, reduced need for sleep, or expansive behavior require active reassessment, not automatic reassurance that activation always settles. [1] [9]

If there is no response after four weeks at a recognized therapeutic dose, check adherence, tolerability, diagnosis, ongoing stressors, and comorbid illness before deciding among further treatment options. A partial response differs from no response. Dose adjustment within recommended limits, a switch, psychotherapy, or specialist augmentation may be appropriate. After remission, treatment often continues for at least six months, with longer prevention based on relapse risk and preference. [1]

Withdrawal can cause flu-like symptoms, insomnia, nausea, imbalance, sensory disturbances such as electric-shock sensations, and hyperarousal. These may begin soon after a missed dose or rapid reduction, particularly with paroxetine or venlafaxine. Relapse is not the only explanation for distress after stopping medication. Taper in agreed stages, often using smaller proportional reductions as the dose falls, and adapt to symptoms. Fluoxetine's long persistence can delay withdrawal rather than making it impossible.

Washout is directional and drug-specific
Sequence	Label information	Practical interpretation
Fluoxetine to an MAOI	At least five weeks	Active drug and metabolite persist after the final dose.
MAOI to fluoxetine	At least 14 days	Allow enzyme activity to recover after an irreversible MAOI.
Venlafaxine to an MAOI	Effexor XR specifies at least seven days	Also check the receiving MAOI label, which may require longer.
Phenelzine and serotonergic antidepressant switches	Nardil generally specifies at least 14 days, with the longer fluoxetine exception	Follow both product labels and the individualized specialist plan.

A washout interval is not a taper schedule, and a taper does not eliminate an incompatible overlap. Do not reduce these distinctions to a universal two-week rule. In urgent infections requiring linezolid, coordinate with the treating service and pharmacy rather than simply adding it or delaying essential antimicrobial care without a plan. [9] [3] [11]

Reassess the diagnosis and the treatment setting

Pregnancy does not make untreated depression benign, and it does not automatically require stopping or switching an effective medication. Review severity, relapse history, prior response, gestational timing, medication-specific risks, and patient preferences. ACOG advises against withholding or discontinuing treatment solely because of pregnancy or lactation. A stable patient taking paroxetine needs individualized counseling rather than a forced abrupt switch; no drug should be described as having zero fetal or neonatal risk.

Formulation also matters. Zoloft oral solution contains 12% alcohol and its label does not recommend that solution during pregnancy; this is distinct from whether sertraline itself remains an appropriate treatment. [2] [15]

In an older adult, consider falls, anticholinergic burden, sodium, QT risk, bleeding, renal function, and the rest of the medication list. Renal dosing is product-specific. Sertraline's renal labeling does not mean every other SSRI is prohibited in kidney disease. Emotional blunting likewise needs a differential diagnosis, including residual depression and medication effects, before a dose change or switch. Do not promise that changing to one named drug restores a particular feeling.

Depression with psychotic symptoms often warrants specialist care and combined antidepressant and antipsychotic treatment. ECT can be considered when a rapid response is needed, the illness is severe or life-threatening, or other treatments have failed. A patient with a history of mania requires a bipolar treatment plan; routine antidepressant monotherapy is not an appropriate default for bipolar I depression. New mania during antidepressant treatment requires reassessment and antimanic treatment. [1] [20]

For depression with panic or generalized anxiety, select a treatment with evidence for the actual disorders and start cautiously when activation is a concern. NICE does not recommend benzodiazepines for panic disorder and limits their GAD use to short-term crises; bridging is not compulsory. Atypical depressive features do not automatically mandate an MAOI. Specialist options for inadequate response include psychological treatment, switching and selected augmentation such as lithium or an antipsychotic after reviewing risks. [1] [24]

Esketamine's treatment-resistant depression indication permits monotherapy or an oral-antidepressant combination. Its separate indication for depressive symptoms in adults with MDD and acute suicidal ideation or behavior still requires an oral antidepressant. It has not been shown to prevent suicide and does not replace hospitalization when indicated. [18]

Try it here · Checkpoint 3 of 3

Make your prediction before reading the choices. A first attempt is just a starting point.

Case 6

Show answer and explanations

A. Continue the same prescription without discussing the pregnancy or prior relapses. (Why this does not fit)
Continuing treatment may be appropriate, but informed review of medication-specific and untreated-illness risks is still needed.
B. Automatically cross-taper to sertraline based only on the positive pregnancy test. (Why this does not fit)
A switch may be considered in some circumstances, but a stable patient with recurrent illness needs individualized evaluation rather than an automatic switch.
C. Review individualized maternal and fetal risks and prior response before agreeing on a treatment plan. (Best answer)
Pregnancy alone does not require stopping an effective treatment, and the relapse history is directly relevant.
D. Stop paroxetine today and arrange review after the first trimester. (Why this does not fit)
Abrupt cessation can cause withdrawal and relapse and leaves the current treatment decision unaddressed.

Takeaway: Pregnancy decisions require individualized counseling rather than a forced switch.

Case sources: [15] [1]

Prescribing and toxicity cases

These original educational scenarios test selection, adverse effects, interactions, and follow-up. Each has one best answer based on the information provided.

Case 1

Show answer and explanations

A. Clomipramine. (Why this does not fit)
This serotonergic TCA is not a particularly suitable choice for avoiding sexual adverse effects and adds anticholinergic and cardiac burdens.
B. Paroxetine. (Why this does not fit)
Changing to another SSRI, particularly one with a substantial sexual-adverse-effect burden, does not best fit this patient preference to reduce the effect.
C. A higher SSRI dose solely to treat the sexual symptoms. (Why this does not fit)
Increasing serotonergic exposure is not a dependable treatment for an adverse effect that began on the SSRI.
D. Bupropion. (Best answer)
Its different reuptake profile generally carries fewer sexual adverse effects, making it a reasonable switch to discuss with a taper and monitoring plan.

Takeaway: Use the patient's treatment preference and adverse-effect pattern to guide a safe change.

Case sources: [1] [5] [21]

Case 2

Show answer and explanations

A. Direct alpha-1 receptor activation by phenelzine. (Why this does not fit)
The pressor response is indirect: reduced tyramine metabolism permits increased norepinephrine release.
B. Serotonin reuptake inhibition caused by the cheese. (Why this does not fit)
Dietary tyramine is not an SSRI; the meal-MAOI interaction is catecholamine-mediated.
C. Impaired tyramine metabolism with excessive catecholamine release. (Best answer)
MAO inhibition allows a greater pressor response to dietary tyramine, fitting the meal-associated hypertensive emergency.
D. MAO inhibition causes depletion of sympathetic norepinephrine stores. (Why this does not fit)
Depletion would not explain this abrupt pressor reaction; tyramine drives release when its normal metabolism is inhibited.

Takeaway: Tyramine-associated hypertension is a distinct MAOI emergency.

Case sources: [11]

Case 3

Show answer and explanations

A. IV lidocaine as the first treatment before bicarbonate. (Why this does not fit)
Lidocaine can be considered for refractory dysrhythmia after initial treatment; bicarbonate is the first targeted therapy for life-threatening TCA cardiotoxicity.
B. IV sodium bicarbonate with resuscitative monitoring. (Best answer)
Sodium loading and alkalinization counter TCA sodium-channel toxicity in this wide-QRS, hypotensive presentation.
C. IV procainamide. (Why this does not fit)
Additional class Ia sodium-channel blockade can worsen the TCA-associated conduction disturbance.
D. IV magnesium alone to correct the wide QRS. (Why this does not fit)
Magnesium is used for torsades in an appropriate long-QT context; it does not replace bicarbonate for TCA sodium-channel cardiotoxicity.

Takeaway: Wide QRS and hypotension after TCA overdose require urgent bicarbonate-based treatment.

Case sources: [13] [19]

Case 4

Show answer and explanations

A. Serotonin toxicity. (Best answer)
The new serotonergic exposure and neuromuscular excitation fit serotonin toxicity.
B. Uncomplicated opioid intoxication. (Why this does not fit)
Typical opioid poisoning produces depressed consciousness and ventilation rather than this clonus and hyperreflexia pattern.
C. SSRI discontinuation syndrome. (Why this does not fit)
There was a serotonergic addition rather than abrupt cessation, and clonus with autonomic findings requires emergency assessment.
D. Isolated acute dystonia. (Why this does not fit)
Dystonia produces sustained contractions, not the full gastrointestinal and hyperreflexic syndrome described.

Takeaway: Clonus after a serotonergic interaction is a high-value finding.

Case sources: [2] [3]

Case 5

Show answer and explanations

A. Amitriptyline. (Why this does not fit)
Its antimuscarinic effects can worsen urinary retention and add orthostasis despite possible sedation.
B. Bupropion. (Why this does not fit)
Its activating and appetite effects do not best match the prominent insomnia and poor intake.
C. Trazodone 25 mg nightly as the entire depression regimen. (Why this does not fit)
This is a low hypnotic dose, not an adequate antidepressant regimen for the stated major depression.
D. Mirtazapine with monitoring for sedation, weight, and falls. (Best answer)
Its appetite and sleep effects may fit this presentation, with less anticholinergic burden than the listed TCA option.

Takeaway: A useful adverse effect must still be balanced against sedation and fall risk.

Case sources: [6] [7] [19]

Case 7

Show answer and explanations

A. The XL formulation permits routine treatment despite the previous bulimia. (Why this does not fit)
The history-based eating-disorder contraindication applies despite extended-release formulation.
B. The prior bulimia diagnosis remains a labeled contraindication. (Best answer)
The contraindication includes current or prior bulimia or anorexia, not only active purging or a previous seizure.
C. Bupropion is suitable because purging is no longer active. (Why this does not fit)
Resolution of current behavior does not erase the label's history-based contraindication.
D. A normal EEG would remove the contraindication. (Why this does not fit)
An EEG does not establish that the eating-disorder-associated seizure risk is absent.

Takeaway: Ask about past as well as current eating disorders before prescribing bupropion.

Case sources: [5]

Case 8

Show answer and explanations

A. Antidepressant withdrawal. (Best answer)
The rapid onset after cessation and sensory symptoms support withdrawal rather than automatically proving depressive relapse.
B. Definite recurrence of major depression. (Why this does not fit)
Depression may recur, but this acute sensory and vestibular pattern after abrupt cessation is more characteristic of withdrawal.
C. Serotonin toxicity. (Why this does not fit)
The onset after missed doses with electric-shock sensations and no clonus or autonomic toxicity favors withdrawal.
D. Vestibular neuritis. (Why this does not fit)
Vestibular disease can cause dizziness, but the multiple sensory and sleep symptoms closely following paroxetine cessation favor withdrawal.

Takeaway: Temporal relation to dose reduction helps distinguish withdrawal from relapse.

Case sources: [1]

Case 9

Show answer and explanations

A. Clomipramine. (Why this does not fit)
Its OCD and antidepressant uses do not make it a standard smoking-cessation medication.
B. Phenelzine. (Why this does not fit)
It is not a usual tobacco-cessation treatment and introduces substantial food and drug interaction requirements.
C. Trazodone. (Why this does not fit)
Sedation does not provide the established tobacco-cessation role associated with bupropion.
D. Bupropion. (Best answer)
Bupropion is used in depression and in smoking cessation formulations, so it can fit both goals after a safety review.

Takeaway: A shared treatment goal can favor a drug, but product details and contraindications still matter.

Case sources: [5]

Case 10

Show answer and explanations

A. A cross-taper eliminates the need for washout. (Why this does not fit)
Overlapping incompatible serotonergic treatment can cause severe toxicity.
B. The washout can be counted from the first taper reduction while full doses continue. (Why this does not fit)
Washout follows discontinuation of the relevant drug, not merely the beginning of a taper.
C. Effexor XR specifies at least seven days after stopping, but Nardil generally requires at least 14 days after serotonergic agents; follow both labels. (Best answer)
The apparent conflict reflects the departing and receiving product requirements, so the shorter interval alone should not dictate this switch.
D. Seven days is always adequate for every antidepressant-to-MAOI switch. (Why this does not fit)
Fluoxetine and receiving-product requirements make a universal seven-day rule incorrect.

Takeaway: Check both ends of an antidepressant switch.

Case sources: [3] [11]

Case 11

Show answer and explanations

A. Phenelzine. (Why this does not fit)
Phenelzine does not have the specific combined MDD and diabetic peripheral neuropathic-pain indications of duloxetine.
B. Duloxetine. (Best answer)
It has indications for depression and diabetic peripheral neuropathic pain, and the stem does not identify its major organ-function exclusions.
C. Fluoxetine. (Why this does not fit)
Fluoxetine treats depression but lacks the specific diabetic peripheral neuropathic-pain indication asked about.
D. Mirtazapine. (Why this does not fit)
Appetite and sleep benefits do not establish efficacy for the diabetic neuropathic-pain indication in this question.

Takeaway: A pain indication can help select among otherwise reasonable antidepressants.

Case sources: [4]

Case 12

Show answer and explanations

A. Emergency evaluation now and stop trazodone pending assessment. (Best answer)
A prolonged erection can threaten tissue even without severe pain and requires urgent treatment.
B. Stop trazodone and observe at home until the following morning. (Why this does not fit)
A painful erection persisting beyond four hours needs urgent assessment; stopping the drug alone does not resolve the ischemic risk.
C. Reduce the next trazodone dose and use a nonprescription analgesic. (Why this does not fit)
Dose reduction does not address the current prolonged painful erection.
D. Arrange a routine outpatient urology visit later in the month. (Why this does not fit)
The duration makes this an emergency, not a routine referral.

Takeaway: Trazodone-associated priapism requires urgent assessment.

Case sources: [7]

Case 13

Show answer and explanations

A. Withhold hypertonic saline until sodium is below 120 mmol/L. (Why this does not fit)
Clinical severity, not that single cutoff, determines emergency treatment.
B. Use fluid restriction alone while the seizure continues. (Why this does not fit)
Fluid restriction does not provide adequate immediate treatment for severe neurologic symptoms.
C. Correct sodium to normal as rapidly as possible without serial measurements. (Why this does not fit)
Overcorrection can cause serious neurologic injury; correction requires close monitoring and limits.
D. Treat the symptomatic emergency with monitored hypertonic saline and address the suspected cause. (Best answer)
Severe neurologic symptoms warrant urgent treatment without waiting for sodium to fall below an arbitrary threshold.

Takeaway: Hyponatremia treatment is guided by symptoms and safe correction, not a single number.

Case sources: [14] [2]

Case 15

Show answer and explanations

A. Delay all antimicrobial treatment for a full antidepressant washout without considering infection urgency. (Why this does not fit)
A serious infection may require immediate treatment. Coordinate antibiotic selection and the antidepressant plan rather than delaying essential care automatically.
B. Coordinate the urgent antibiotic and antidepressant plan with the treating team. (Best answer)
Linezolid has MAOI activity; the need for effective infection treatment and serotonin-toxicity prevention must be addressed together.
C. Continue sertraline with linezolid and defer interaction review until routine follow-up. (Why this does not fit)
Linezolid inhibits MAO and can interact with sertraline. The plan and monitoring must be addressed before or during urgent initiation.
D. Replace sertraline with fluoxetine immediately to eliminate the interaction. (Why this does not fit)
Fluoxetine is also serotonergic and has prolonged persistence; this does not solve the interaction.

Takeaway: Medication reconciliation must include nonpsychiatric serotonergic interactions.

Case sources: [2] [11]

Case 16

Show answer and explanations

A. Assess residual depression and medication effects before changing treatment. (Best answer)
Emotional blunting has more than one possible contributor, and the management should match the assessment.
B. Switch to vortioxetine without reviewing residual depressive symptoms or the medication history. (Why this does not fit)
A switch may be reasonable after assessment, but the complaint alone does not identify a guaranteed remedy or exclude residual illness.
C. Double the dose without evaluating residual symptoms or adverse effects. (Why this does not fit)
More exposure may worsen a medication-related problem and bypasses the needed assessment.
D. Abruptly stop medication today to test the diagnosis. (Why this does not fit)
An unplanned abrupt stop risks withdrawal and relapse.

Takeaway: A reported adverse experience deserves assessment and shared adjustment, not a guaranteed drug match.

Case sources: [1] [8]

Case 17

Show answer and explanations

A. Testosterone despite normal testosterone testing. (Why this does not fit)
Hormone replacement is not appropriate without a supported deficiency; the trial-supported symptom-targeted option here is sildenafil.
B. Aripiprazole to augment the remitted depression. (Why this does not fit)
Augmentation for inadequately treated depression is a different indication; this patient needs assessment and treatment of erectile difficulty.
C. Increase sertraline to treat the erectile symptom as residual depression. (Why this does not fit)
Depression is in remission and the erectile difficulty began on treatment. Increasing the suspected drug is not the symptom-targeted adjunct supported by the cited trial.
D. Sildenafil. (Best answer)
A randomized placebo-controlled trial in men with remitted depression and SRI-associated sexual dysfunction supports benefit. This does not guarantee improvement in every sexual symptom or population.

Takeaway: Match the intervention and its evidence to the specific sexual symptom and patient.

Case sources: [16] [2]

Case 18

Show answer and explanations

A. Reduce citalopram from 40 mg to 20 mg and defer repeat ECG assessment for several months. (Why this does not fit)
Persistent QTc above 500 ms warrants discontinuation under the label and prompt review of reversible causes and alternatives.
B. Continue the same dose because the patient has not had syncope. (Why this does not fit)
Absence of syncope does not negate the high-risk QT finding.
C. Discontinue citalopram under an appropriate clinical plan and evaluate the cardiac risk. (Best answer)
Persistent QTc above 500 ms meets the label's discontinuation instruction, and 40 mg also exceeds the recommended maximum for this age.
D. Continue 40 mg because the adult maximum applies at every age. (Why this does not fit)
The recommended maximum is 20 mg daily above age 60.

Takeaway: Age-specific dosing and a persistent dangerous QT interval are separate reasons for action.

Case sources: [10]

Case 19

Show answer and explanations

A. The waiting period is needed only when switching from phenelzine to fluoxetine. (Why this does not fit)
That reverse switch also needs separation, but the especially long interval applies after fluoxetine.
B. Fluoxetine requires at least a five-week interval before an MAOI because active drug and metabolite persist. (Best answer)
The long persistence makes a standard two-week interval inadequate for this direction of switching.
C. A seven-day interval is sufficient because fluoxetine has no long-lived active metabolite. (Why this does not fit)
Norfluoxetine is active and prolonged exposure explains the five-week minimum interval.
D. An MAOI can safely overlap if the fluoxetine dose was low. (Why this does not fit)
Dose does not erase the labeled interaction or washout requirement.

Takeaway: Fluoxetine is a critical exception to a generic two-week washout rule.

Case sources: [9] [11]

Case 20

Show answer and explanations

A. Arrange an alcohol-free formulation plan while preserving effective depression care. (Best answer)
The product label does not recommend the alcohol-containing oral solution during pregnancy; that does not itself require abandoning sertraline treatment.
B. Use the solution unchanged because only the active ingredient matters in pregnancy. (Why this does not fit)
The alcohol-containing formulation creates a separate labeled concern even though the active drug is familiar.
C. Dilute the measured solution and describe it as alcohol-free. (Why this does not fit)
Dilution changes concentration but does not eliminate the amount of alcohol in the administered dose.
D. Abruptly stop all antidepressant treatment solely because this formulation is unsuitable. (Why this does not fit)
A formulation problem should prompt a coordinated alternative, not an automatic interruption of effective care.

Takeaway: Formulation ingredients can change prescribing even when the active drug remains appropriate.

Case sources: [2] [15]

Case 21

Show answer and explanations

A. Continue unchanged and manage the restlessness only with sleep-hygiene advice. (Why this does not fit)
Intense restlessness or suicidal thoughts require prompt assessment; sleep advice alone is insufficient.
B. Wait until eight weeks because antidepressants need time to work. (Why this does not fit)
Expected onset of benefit does not justify delaying assessment of new suicidality.
C. Increase the dose to suppress the restlessness without assessment. (Why this does not fit)
Additional exposure could worsen the problem and bypasses safety evaluation.
D. Prompt safety assessment and medication review for activation. (Best answer)
Severe restlessness with new self-harm thoughts requires active evaluation rather than waiting for routine follow-up.

Takeaway: Early activation plus suicidality is an assessment priority.

Case sources: [1] [9]

Case 22

Show answer and explanations

A. The remaining effect proves impaired renal clearance of unchanged fluoxetine. (Why this does not fit)
Prolonged activity can occur without renal disease because fluoxetine and its active metabolite are slowly eliminated.
B. Lack of early withdrawal means the drug has already left the body. (Why this does not fit)
Residual exposure can delay withdrawal symptoms, so their absence does not prove clearance.
C. Fluoxetine and norfluoxetine can remain active for weeks after dosing stops. (Best answer)
Long elimination explains carryover interactions without implying that stopping the drug creates new drug.
D. The absence of early withdrawal makes a short MAOI washout adequate. (Why this does not fit)
Symptoms do not determine the interaction washout. The fluoxetine label requires at least five weeks before an MAOI.

Takeaway: A drug can remain pharmacologically relevant after its last dose.

Case sources: [9]

Case 23

Show answer and explanations

A. Use renal function as the only determinant of sertraline suitability. (Why this does not fit)
Hepatic impairment, other drugs and adverse effects still influence safe use despite the renal dosing statement.
B. No sertraline dose adjustment is required solely for renal impairment. (Best answer)
Its renal labeling supports this distinction without making it uniquely safe for every patient.
C. Reduce sertraline to one-quarter of the usual dose solely because the GFR is below 30. (Why this does not fit)
The label does not require adjustment solely for renal impairment, although other patient factors may support cautious dosing.
D. Duloxetine is automatically interchangeable at full dose in severe renal impairment. (Why this does not fit)
Duloxetine has a different labeling precaution below GFR 30 mL/min.

Takeaway: Use the individual product's organ-function guidance.

Case sources: [2] [4]

Case 24

Show answer and explanations

A. Reassess the venlafaxine dose or treatment and manage the sustained blood-pressure increase. (Best answer)
Venlafaxine can increase blood pressure, so persistent change warrants action rather than routine continuation.
B. Continue the dose unchanged and repeat the blood pressure only at the next annual review. (Why this does not fit)
A sustained increase needs timely assessment and consideration of dose reduction or discontinuation.
C. Switch directly to another SNRI without further blood-pressure monitoring. (Why this does not fit)
Other SNRIs can also affect blood pressure; selection and follow-up still require review.
D. Treat the readings as anxiety-related without checking repeated measurements or other causes. (Why this does not fit)
The sustained readings and drug exposure warrant assessment rather than presumptive dismissal.

Takeaway: A sustained vital-sign change can be a medication-selection problem.

Case sources: [3]

Case 25

Show answer and explanations

A. Select a TCA without considering overdose access because it previously helped sleep. (Why this does not fit)
Past symptom benefit must be balanced against serious overdose toxicity and current risk.
B. Give a routine large supply of an SSRI without discussing medication access. (Why this does not fit)
Lower relative toxicity is not absence of harm; supply and access should match the individualized risk assessment.
C. Withhold all depression treatment solely because suicide risk is present. (Why this does not fit)
The risk requires a safer coordinated treatment plan, not abandonment of care.
D. Consider overdose toxicity and medication access when selecting and dispensing treatment. (Best answer)
Both product toxicity and available quantity matter in this patient's immediate treatment plan.

Takeaway: Overdose safety includes drug selection, supply, and the broader safety plan.

Case sources: [1] [19] [5]

Case 26

Show answer and explanations

A. Classify the illness as treatment-resistant after this single trial. (Why this does not fit)
One unsuccessful trial does not by itself establish the usual treatment-resistance construct; adequacy and diagnosis must be reviewed.
B. Stop treatment without discussing alternatives or withdrawal. (Why this does not fit)
An unplanned stop does not address the ongoing illness and may produce withdrawal.
C. Reassess diagnosis, adherence, context, and treatment options. (Best answer)
A four-week review of no response is appropriate; the next decision depends on this assessment rather than an automatic deadline.
D. Prohibit any reassessment until week eight. (Why this does not fit)
Guidance supports earlier review, especially with no response.

Takeaway: No response calls for structured reassessment before choosing the next treatment.

Case sources: [1]

Case 28

Show answer and explanations

A. Use a bipolar depression plan rather than antidepressant monotherapy. (Best answer)
The documented mania changes the diagnosis and the risks of the proposed treatment.
B. Treat with SSRI monotherapy because the prior manic episode has resolved. (Why this does not fit)
A history of mania changes the diagnosis and treatment plan even during the depressive phase.
C. Choose venlafaxine monotherapy because activation is desirable in bipolar depression. (Why this does not fit)
Antidepressant monotherapy is not an appropriate default for bipolar I depression and may destabilize mood.
D. Start lamotrigine at a full maintenance dose to avoid antidepressant exposure. (Why this does not fit)
A bipolar plan is needed, but lamotrigine must be titrated safely; a high starting dose is not an acceptable shortcut.

Takeaway: The same depressive symptoms require different prescribing when prior mania is present.

Case sources: [1] [20]

Case 29

Show answer and explanations

A. Use a hypnotic alone and postpone specialist assessment for eight weeks. (Why this does not fit)
A sleep-focused regimen does not address severe psychotic depression or the need for rapid response.
B. Use routine outpatient psychotherapy alone without assessing medical or psychiatric urgency. (Why this does not fit)
Psychotherapy may have a role but does not replace urgent evaluation of this severe presentation.
C. Use antipsychotic monotherapy as the complete treatment plan without reviewing the depression. (Why this does not fit)
Combined treatment or ECT may be needed; addressing psychosis alone does not provide the full depression plan.
D. Urgent specialist care with consideration of ECT and combined pharmacotherapy. (Best answer)
Psychotic symptoms and potentially life-threatening intake refusal require more than a routine outpatient medication trial.

Takeaway: Severity and psychotic features can change both treatment and urgency.

Case sources: [1]

Case 30

Show answer and explanations

A. Start restrictions only if a blood-pressure increase occurs after a meal. (Why this does not fit)
Dietary precautions are preventive at 9 or 12 mg per 24 hours and should not wait for an adverse event.
B. Stop dietary restrictions the day after reducing back to 6 mg per 24 hours. (Why this does not fit)
The label requires continued restrictions for two weeks after stopping or reducing the higher dose.
C. Begin tyramine dietary restrictions and maintain them for two weeks after later stopping or reducing the higher dose. (Best answer)
The higher patch doses carry dietary precautions that differ from the 6 mg per 24 hour regimen.
D. No dietary counseling is needed at any patch dose. (Why this does not fit)
The absence of a modified-diet requirement at 6 mg does not apply to 9 or 12 mg.

Takeaway: MAOI formulation and dose affect food precautions but do not abolish interaction checks.

Case sources: [12]

Case 31

Show answer and explanations

A. The acute-suicidality MDD indication also permits monotherapy in the same way as TRD. (Why this does not fit)
The separate acute-suicidality depressive-symptom indication still requires an oral antidepressant.
B. TRD treatment may be monotherapy or combined with an oral antidepressant, with supervised administration and at least two hours of monitoring. (Best answer)
The 2025 expansion permits monotherapy for TRD while retaining the restricted monitored setting.
C. Observation can routinely end after 30 minutes if dissociation has resolved. (Why this does not fit)
The label requires at least two hours of monitoring and assessment of clinical stability before discharge.
D. Its approval proves that it prevents suicide. (Why this does not fit)
The label specifically states that suicide-prevention effectiveness has not been demonstrated.

Takeaway: A broader indication does not remove monitoring requirements or establish suicide prevention.

Case sources: [18]

Case 32

Show answer and explanations

A. Sexual dysfunction remains possible and should be assessed with other causes. (Best answer)
The drug's multimodal serotonin actions do not eliminate sexual adverse effects.
B. Exclude vortioxetine as a contributor solely because it has multimodal receptor activity. (Why this does not fit)
Its label includes sexual dysfunction; mechanism does not rule out an adverse effect.
C. Diagnose hypogonadism from the symptom alone without examination or testing. (Why this does not fit)
Endocrine causes belong in the assessment but cannot be established from this symptom alone.
D. Add a serotonergic antidepressant before reviewing the existing treatment. (Why this does not fit)
Adding another drug before assessing the adverse effect can compound risk and does not establish a targeted solution.

Takeaway: A different serotonergic mechanism does not guarantee freedom from a class-associated problem.

Case sources: [8]

Sources

NICE NG222 depression in adults recommendations (2022)
Shared treatment selection, response review, withdrawal, psychotic depression, and ECT.
Zoloft prescribing information
SSRI mechanism, sexual effects, bleeding, SIADH, interactions, and renal dosing. Pregnancy formulation warning for alcohol-containing oral solution.
Effexor XR prescribing information
SNRI mechanism, blood pressure, discontinuation, and direction-specific MAOI washout.
Duloxetine prescribing information
Depression and pain indications, renal and hepatic precautions.
Wellbutrin XL prescribing information
Bupropion pharmacology, dose-related seizures, eating-disorder contraindication, and overdose.
Remeron prescribing information
Mirtazapine alpha-2, serotonin and histamine receptor effects, appetite, weight, and sedation.
Trazodone prescribing information
Antidepressant mechanism, sedation, orthostasis, and priapism.
Trintellix prescribing information
Vortioxetine multimodal serotonergic pharmacology and sexual adverse effects.
Prozac prescribing information
Fluoxetine persistence, MAOI washout, bulimia, and suicidality warning.
Celexa prescribing information
Age-related maximum dose, QT precautions, and persistent QTc above 500 ms.
Nardil prescribing information
Tyramine interaction, hypertensive crisis, serotonergic contraindications, and washout.
Emsam prescribing information
Transdermal selegiline and dose-specific tyramine dietary precautions.
AHA 2025 special circumstances of resuscitation (2025)
Sodium bicarbonate for TCA cardiotoxicity and selected use of lidocaine for refractory dysrhythmia.
Society for Endocrinology emergency hyponatraemia guidance (2022)
Symptom-based emergency hypertonic saline treatment and prevention of overcorrection.
ACOG Clinical Practice Guideline No. 5: treatment and management of mental health conditions during pregnancy and postpartum (2023)
Original ACOG guideline, publicly hosted copy; individualized perinatal medication decisions and recommendation against stopping solely for pregnancy or lactation.
Sildenafil for antidepressant-associated sexual dysfunction randomized trial (2003)
Evidence for sildenafil in men with remitted depression and SRI-associated sexual dysfunction.
Savella FDA prescribing information (2024)
Milnacipran US fibromyalgia indication rather than an MDD indication.
Spravato FDA prescribing information (2025)
TRD monotherapy expansion, monitored administration, and limits of suicide-prevention evidence.
Nortriptyline prescribing information
Tricyclic adverse effects, cardiac conduction toxicity, and overdose.
NICE CG185 bipolar disorder recommendations (2014)
Bipolar depression and management of mania arising during antidepressant treatment.
Randomized comparison of bupropion SR and sertraline, including sexual functioning (1999)
Comparative sexual adverse effects supporting individualized antidepressant selection.
Bupropion XL in adult ADHD randomized placebo-controlled trial (2005)
Evidence underlying a bounded off-label adult ADHD teaching point.
AGS 2023 Beers Criteria (2023)
Anticholinergic antidepressants including paroxetine and nortriptyline; older-adult safety rather than a universal prescribing ban.
NICE CG113 GAD and panic disorder recommendations (2011)
GAD preference-based psychological or drug care, and panic treatment without routine benzodiazepine bridging.
Medsafe: Serotonin syndrome/toxicity reminder (2010)
Official historical safety communication: supportive treatment, severe-case airway support and reported use of serotonin antagonists such as cyproheptadine.
Nortriptyline NRIM New Zealand data sheet (2013-05-09)
Pharmacodynamic comparison with amitriptyline; lower anticholinergic activity is not absence of anticholinergic adverse effects.

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