Can we start a selective serotonin reuptake inhibitor (SSRI) for anxiety in a patient on diazepam (10 mg daily) and zopiclone (5 mg daily) while tapering the diazepam dose?

Starting an SSRI While Tapering Diazepam in an Elderly Patient

Yes, you can safely initiate an SSRI while tapering diazepam in this elderly patient, but you must start the SSRI at a low dose, increase it slowly, and maintain close monitoring during the first 24-48 hours after each dose adjustment. 1

Key Safety Considerations

Drug Interaction Profile

• SSRIs do not have direct contraindications with benzodiazepines or Z-drugs (zopiclone), unlike MAOIs which are absolutely contraindicated with SSRIs 1
• The primary concern is additive CNS depression when combining these agents, particularly in elderly patients who are at higher risk for falls, confusion, and oversedation 1

SSRI Selection for This Patient

Choose escitalopram or citalopram as first-line options because they have the least effect on CYP450 isoenzymes and therefore the lowest propensity for drug interactions 1

• Avoid fluvoxamine - it has extensive CYP450 interactions (CYP1A2, CYP2C19, CYP2C9, CYP3A4, CYP2D6) which could affect zopiclone metabolism 1
• Use caution with paroxetine - it has higher discontinuation syndrome risk and increased suicidal thinking compared to other SSRIs 1
• Citalopram dosing caveat: Do not exceed 20 mg daily in elderly patients due to QT prolongation risk 1

Implementation Strategy

Initiation Protocol

1. Start with a subtherapeutic "test" dose of the SSRI to assess tolerability, as initial adverse effects can include anxiety and agitation 1
2. Begin escitalopram at 5 mg daily or citalopram at 10 mg daily in this elderly patient 2
3. Maintain the current diazepam dose initially while introducing the SSRI to avoid compounding withdrawal symptoms with SSRI initiation side effects

Titration Timeline

• Increase SSRI dose slowly: For shorter half-life SSRIs (escitalopram, citalopram), increase at 1-2 week intervals as tolerated 1
• Monitor intensively during the first 24-48 hours after each dose change for signs of serotonin syndrome, behavioral activation, or excessive sedation 1
• Begin diazepam taper only after SSRI reaches therapeutic dose and the patient has stabilized (typically 2-4 weeks) 3, 4

Diazepam Tapering Approach

• Taper diazepam slowly - reduce by no more than 10-25% every 1-2 weeks to minimize withdrawal symptoms and rebound anxiety
• The SSRI will provide anxiety coverage as the benzodiazepine is reduced, but full SSRI efficacy takes 6-12 weeks 1
• Consider maintaining a low dose of diazepam (2.5-5 mg daily) temporarily during the SSRI titration phase for anxiety control

Critical Monitoring Parameters

Watch for These Complications

• Behavioral activation/agitation: More common in elderly patients, especially early in treatment or with dose increases 1
• Falls risk: The combination of SSRI, benzodiazepine, and Z-drug significantly increases fall risk in elderly patients 1
• Benzodiazepine withdrawal symptoms: Anxiety, insomnia, tremor, confusion - may be difficult to distinguish from SSRI side effects
• Serotonin syndrome: Though rare without MAOIs, monitor for confusion, agitation, tremors, hyperreflexia, autonomic instability within 24-48 hours of dose changes 1

Zopiclone Considerations

• Zopiclone 5 mg can be continued during this transition, as it does not have significant interactions with SSRIs 5
• However, consider eventual taper of zopiclone as well, since SSRIs can improve sleep quality once therapeutic levels are achieved 2, 3
• Zopiclone may cause less daytime anxiety than benzodiazepines like triazolam, but still carries CNS depression risk 5

Common Pitfalls to Avoid

• Do not start both SSRI and benzodiazepine taper simultaneously - this creates confusion about symptom etiology and increases patient distress
• Do not use paroxetine in elderly patients - higher discontinuation syndrome risk and suicidal thinking compared to other SSRIs 1
• Do not exceed citalopram 20 mg daily in elderly patients due to cardiac conduction risks 1
• Do not rush the SSRI titration - slower is safer in elderly patients, and higher doses do not necessarily improve outcomes 1

This approach prioritizes patient safety while transitioning from benzodiazepine dependence to more appropriate long-term anxiety management with an SSRI. 3, 4