From the FDA Drug Label
Mirtazapine should be used with caution in patients with known cardiovascular or cerebrovascular disease that could be exacerbated by hypotension (history of myocardial infarction, angina, or ischemic stroke) and conditions that would predispose patients to hypotension (dehydration, hypovolemia, and treatment with antihypertensive medication)
The use of Mirtazapine in patients with pre-existing vascular conditions or small vessel disease may be associated with an increased risk of exacerbating these conditions due to its potential to cause orthostatic hypotension. Therefore, caution is advised when prescribing Mirtazapine to these patients 1. Key considerations include:
- History of myocardial infarction, angina, or ischemic stroke
- Conditions that predispose to hypotension, such as dehydration, hypovolemia, and treatment with antihypertensive medication It is essential to carefully weigh the benefits and risks of Mirtazapine treatment in patients with pre-existing vascular conditions or small vessel disease.
From the Research
Mirtazapine poses significant risks for patients with pre-existing vascular conditions or small vessel disease, and its use should be carefully considered and monitored due to its potential to worsen these conditions through various mechanisms, as suggested by studies such as 2 and 3.
Risks Associated with Mirtazapine
Mirtazapine can lead to weight gain, increased appetite, and metabolic changes that negatively impact vascular health. It can also cause fluid retention and edema, exacerbating cardiovascular strain. For patients with small vessel disease, mirtazapine's effects on blood pressure regulation and potential orthostatic hypotension could increase the risk of cerebrovascular events. Additionally, mirtazapine has been associated with rare cases of QT interval prolongation, problematic in patients with underlying cardiovascular disease.
Considerations for Prescribing Mirtazapine
When prescribing mirtazapine to patients with vascular conditions, starting at lower doses (7.5-15mg daily) is advisable, with careful monitoring of cardiovascular parameters, weight, and metabolic markers. Regular follow-up appointments should assess for any worsening of vascular symptoms. These risks stem from mirtazapine's action on multiple neurotransmitter systems, particularly its antagonism of histamine H1 receptors (causing weight gain) and alpha-1 adrenergic receptors (affecting blood pressure regulation).
Evidence and Recommendations
A study from 2 suggests that SSRIs may have cardioprotective benefits compared to mirtazapine, indicating a need for caution when choosing mirtazapine for patients with cardiovascular risks. Furthermore, a systematic review and meta-analysis 3 found that patients taking mirtazapine were at a greater risk of gastrointestinal bleeding than those not taking antidepressants, suggesting that mirtazapine may not be as safe as previously thought for patients at risk of bleeding. Therefore, the decision to prescribe mirtazapine should be made with caution, considering the potential risks and closely monitoring patients for adverse effects, as supported by the most recent and highest quality evidence available, such as 2 and 3.