Tapering Antidepressants in a 75-Year-Old Patient on Lexapro and Mirtazapine
In a 75-year-old patient taking both escitalopram (Lexapro) and mirtazapine, taper off the mirtazapine first due to its significantly higher risk profile in elderly patients, including orthostatic hypotension, falls, cognitive impairment, and sedation. 1
Primary Rationale for Tapering Mirtazapine First
Mirtazapine appears on the American Geriatrics Society Beers Criteria® as a medication requiring extreme caution in older adults due to substantial risks of orthostatic hypotension, falls, and cognitive impairment. 1 The sedating properties of mirtazapine pose particular dangers in the elderly population, where falls can lead to serious morbidity and mortality 1.
In contrast, escitalopram (Lexapro) has been extensively studied in elderly patients with cardiovascular disease and appears to be safe, though it carries some risk of QTc prolongation. 2 Among SSRIs, sertraline has the lowest risk of QTc prolongation, but escitalopram remains a reasonable choice with appropriate monitoring 2.
Safety Considerations Specific to Elderly Patients
Mirtazapine Risks in the Elderly:
- Orthostatic hypotension leading to falls and fractures 1
- Cognitive impairment and increased delirium risk 1
- Sedation that paradoxically worsens at lower doses 3
- Weight gain and metabolic effects 2, 4
- Requires dose reduction (approximately 50% of standard adult dose) in elderly patients 1
Escitalopram Considerations:
- Generally well-tolerated in elderly patients with depression and anxiety 2
- QTc prolongation risk is present but manageable with ECG monitoring 2
- Hyponatremia risk exists, particularly when combined with diuretics or ACE inhibitors 5
Tapering Protocol
Taper mirtazapine gradually over several weeks to avoid withdrawal symptoms, including panic attacks, anxiety, and sleep disturbance. 6 A case report documented severe, recurrent panic attacks occurring after abrupt discontinuation of mirtazapine even after only 10 weeks of treatment, with symptoms persisting until the medication was reintroduced 6.
Recommended tapering approach:
- Reduce mirtazapine by 25% every 1-2 weeks 1
- Monitor for withdrawal symptoms including anxiety, insomnia, panic attacks, and mood destabilization 6
- Maintain escitalopram at current dose during mirtazapine taper to preserve mood stability 2
- Monitor blood pressure (sitting and standing) at each dose reduction to assess for orthostatic changes 1
Monitoring During Taper
Essential monitoring parameters include:
- Fall risk assessment at each visit 1
- Cognitive function screening 1
- Blood pressure (orthostatic measurements) 1
- Mood and anxiety symptoms weekly during taper 6
- Sleep quality, as mirtazapine withdrawal may cause rebound insomnia 3
Common Pitfalls to Avoid
Do not abruptly discontinue mirtazapine, even after relatively short treatment durations, as withdrawal symptoms can be severe and persistent 6. The case literature demonstrates that panic attacks and anxiety can emerge within 48 hours of abrupt cessation and may persist for weeks 6.
Do not assume lower doses of mirtazapine are safer in terms of sedation—paradoxically, sedation may be more pronounced at subtherapeutic doses (below 15mg) due to predominant antihistamine effects 3.
Avoid tapering both medications simultaneously, as this increases the risk of mood destabilization and makes it difficult to identify which medication is causing withdrawal symptoms 2.
Alternative Consideration
If the clinical indication was to reduce polypharmacy while maintaining antidepressant coverage, keeping escitalopram as monotherapy is preferable given its superior safety profile in elderly patients and established efficacy in this population. 2, 5 Mirtazapine's additional benefits for appetite stimulation and sleep may not outweigh its fall risk and cognitive effects in a 75-year-old patient 2, 1.