From the Guidelines
Chronic use of mirtazapine can increase the risk of falls and weakness in elderly patients due to its sedative effects, dizziness, and orthostatic hypotension. Mirtazapine, an antidepressant commonly prescribed for depression and sleep disorders, can cause side effects that are particularly problematic for older adults. These include sedation, dizziness, and orthostatic hypotension (sudden drop in blood pressure when standing up), all of which can contribute to falls and a general sense of weakness. The sedative effects are most pronounced at lower doses (7.5-15mg) and may persist during daytime hours, especially with long-term use. Elderly patients often have reduced drug metabolism and clearance, leading to higher blood levels and prolonged effects of the medication. Additionally, mirtazapine may interact with other medications commonly taken by older adults, potentially exacerbating these side effects. For elderly patients on mirtazapine who experience falls or weakness, healthcare providers should consider dose reduction, switching to a less sedating antidepressant, or implementing fall prevention strategies, as suggested by recent studies 1. The risk-benefit ratio should be carefully evaluated, as untreated depression itself can contribute to functional decline and fall risk in older adults. Key considerations include:
- Monitoring for signs of sedation, dizziness, and orthostatic hypotension
- Adjusting the dose or switching to a less sedating antidepressant if necessary
- Implementing fall prevention strategies, such as removing tripping hazards and improving lighting
- Regularly reviewing the patient's medication regimen to minimize potential interactions and adverse effects, as recommended by recent guidelines 1.
From the FDA Drug Label
In patients with symptomatic hyponatremia, discontinue mirtazapine tablets and institute appropriate medical intervention Elderly patients, patients taking diuretics, and those who are volume- depleted may be at greater risk of developing hyponatremia [see Use in Specific Populations (8.5)]. Signs and symptoms of hyponatremia include headache, difficulty concentrating, memory impairment, confusion, weakness, and unsteadiness, which may lead to falls
Chronic use of mirtazapine can cause falls and weakness in elderly patients due to the risk of hyponatremia, which may lead to symptoms such as weakness and unsteadiness, increasing the risk of falls 2.
- Key factors that increase the risk of hyponatremia in elderly patients include:
- Age
- Use of diuretics
- Volume depletion
- Precautions should be taken when administering mirtazapine to elderly patients, including conservative dose selection and monitoring for signs of hyponatremia 2.
From the Research
Chronic Use of Mirtazapine and Falls in the Elderly
- The relationship between chronic use of mirtazapine and the risk of falls in the elderly is complex and has been studied in various research papers 3, 4, 5, 6.
- A study published in 2025 found that mirtazapine was associated with a higher risk of mortality compared to sertraline, but the risk of falls and fractures within 90 days was not statistically significantly different between the groups 3.
- However, another study published in 2017 found that the risk of hip fracture was increased for mirtazapine users, especially when combined with other antidepressants such as selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants (TCAs) 4.
- In contrast, a study published in 2019 found that mirtazapine did not appear to increase the risk of falls in older hospitalized patients, although the use of multiple psychoactive drugs was a separate risk factor for falls 5.
- A review published in 2009 noted that sedation, insomnia, and impaired sleep, as well as orthostatic hypotension, cardiac rhythm and conduction disorders, and movement disorders, have all been postulated as contributing factors to falls in patients taking antidepressants, including mirtazapine 6.
- Orthostatic hypotension, which can be caused by various factors including autonomic nervous system dysfunction, has been associated with an increased risk of falls and adverse outcomes, including mortality 7.
Risk Factors for Falls
- Several factors can contribute to the risk of falls in the elderly, including:
- Medication use, such as long-acting benzodiazepines, SNRIs, Z-drugs, and low-potency neuroleptics 5
- Medical conditions, such as Parkinson's syndrome, delirium, and hyponatremia 5
- Psychoactive polypharmacy, which can increase the risk of falls 5
- Orthostatic hypotension, which can be caused by various factors including autonomic nervous system dysfunction 7
Mirtazapine and Weakness
- There is limited evidence on the specific relationship between chronic use of mirtazapine and weakness in the elderly.
- However, a study published in 2017 found that the combination of mirtazapine with other antidepressants, such as SSRIs or TCAs, was associated with an increased risk of hip fracture, which could be related to weakness or impaired mobility 4.