What is the next best medication for a 69-year-old inpatient with depression, suicidal ideation, and possible cognitive issues, currently on 100mg of Zoloft (sertraline)?

Medication Recommendation for Treatment-Resistant Depression with Suicidal Ideation in Elderly Patient

Given this patient's persistent suicidal ideation despite SSRI therapy, worsening confusion with antipsychotic augmentation, and possible cognitive impairment, I recommend adding lithium augmentation to the current sertraline regimen at a low dose (150 mg daily, targeting blood levels of 0.2-0.6 mEq/L), as lithium has the strongest evidence for reducing suicidal behaviors in depressed patients. 1

Rationale for Lithium Augmentation

Evidence for Suicide Risk Reduction

• Lithium has demonstrated specific anti-suicide effects in patients with unipolar depression, with multiple cohort studies and systematic reviews showing that lithium maintenance therapy is associated with fewer suicidal behaviors and deaths 1
• This is particularly critical given your patient's recent suicide attempt and ongoing suicidal ideation 1
• The anti-suicide effect of lithium appears independent of its antidepressant properties, making it uniquely suited for this high-risk situation 1

Dosing Considerations for Elderly Patients

• Start with 150 mg daily, as elderly patients are prone to neurotoxicity at higher doses 1
• Target therapeutic blood levels of 0.2-0.6 mEq/L (lower than standard psychiatric dosing) 1
• This dosage range (150-300 mg daily) is generally adequate for augmentation in older adults 1
• Monitor renal function, thyroid function, and lithium levels closely given age-related pharmacokinetic changes 1

Why Not Other Options?

Avoiding Antipsychotics

• You correctly discontinued risperidone after it caused increased confusion 1
• Antipsychotics should only be used when depression is accompanied by psychosis, which is not described in this case 1
• The cognitive impairment risk is particularly problematic given the family history of dementia 1

Optimizing Current SSRI First

• Before switching antidepressants, consider that you recently reduced sertraline from 200mg to 100mg 1
• The dose reduction may have contributed to treatment failure and increased suicidal ideation 1
• Sertraline is well-tolerated and has less effect on metabolism of other medications compared to other SSRIs, making it appropriate for elderly patients 1
• Maximum dose is 200mg daily 1

Alternative Medication Strategies if Lithium Fails or Is Not Tolerated

Consider Ketamine Infusion for Acute Suicidal Crisis

• Ketamine (0.5 mg/kg single infusion) produces rapid improvement in suicidal ideation within 24 hours, lasting at least 1 week 1
• In meta-analyses, 55% of patients had no suicidal ideation at 24 hours and 60% at 7 days 1
• This provides a bridge while optimizing longer-term pharmacotherapy 1
• Particularly valuable in inpatient settings where immediate intervention is needed 1

Switching Antidepressants (Second-Line)

• If augmentation fails, switching to another second-generation antidepressant is reasonable, though no specific agent is superior 1
• For elderly patients with cognitive concerns, preferred agents include escitalopram, citalopram, or mirtazapine 1
• Avoid paroxetine and fluoxetine in older adults due to higher rates of adverse effects 1
• Mirtazapine (starting 7.5mg at bedtime, maximum 30mg) may be particularly useful as it promotes sleep, is well-tolerated, and has faster onset of action 1

SNRIs as Alternative

• Venlafaxine or duloxetine are slightly more effective than SSRIs for depression symptoms but have higher rates of nausea and vomiting 1
• May be considered if SSRI augmentation strategies fail 1

Critical Monitoring Requirements

Suicide Risk Assessment

• Monitor closely for increases in suicidal thoughts and behaviors beginning within 1-2 weeks of any medication change 1
• Risk for suicide attempts is greatest during the first 1-2 months of treatment 1
• Watch for emergence of agitation, irritability, or unusual behavioral changes 1

Cognitive Function Monitoring

• Given possible cognitive impairment and family history of dementia, avoid medications with significant anticholinergic effects 1
• Monitor for worsening confusion with any new medication 1
• Lithium neurotoxicity can manifest as confusion, so careful dose titration is essential 1

Treatment Response Timeline

• Assess response within 6-8 weeks of initiating augmentation strategy 1
• If inadequate response, modify treatment rather than continuing ineffective therapy 1
• Consider that only 50% of patients respond to initial antidepressant therapy 1

Essential Non-Pharmacologic Interventions

Psychotherapy Integration

• Cognitive behavioral therapy (CBT) reduces suicidal ideation and behavior by more than 50% in patients with recent suicide attempts 1
• Most patients benefit from fewer than 12 CBT sessions 1
• Dialectical behavior therapy (DBT) is also effective for reducing self-directed violence, particularly if personality factors contribute 1
• These should be implemented concurrently with medication optimization 1

Common Pitfalls to Avoid

• Do not prematurely discontinue or reduce SSRI dose in patients with ongoing depression and suicidal ideation 1
• Do not use antipsychotics for augmentation unless psychotic features are present, as they increase confusion risk in elderly patients with cognitive impairment 1
• Do not rely on a single assessment tool for suicide risk—use multiple methods including clinical interview and self-report measures 1
• Do not delay treatment modifications if response is inadequate at 6-8 weeks 1