From the Guidelines
Mirtazapine is primarily used to treat major depressive disorder, and its use is recommended due to its faster onset of action compared to other antidepressants, such as fluoxetine, paroxetine, or sertraline 1. The medication is typically prescribed at doses ranging from 15 to 45 mg once daily, usually taken at bedtime due to its sedating effects.
- Treatment usually begins at a lower dose (15 mg) and may be gradually increased based on response and tolerability.
- Mirtazapine works differently from many other antidepressants as it's classified as a noradrenergic and specific serotonergic antidepressant (NaSSA).
- It increases norepinephrine and serotonin neurotransmission by blocking certain receptors in the brain. Notably, mirtazapine has a unique side effect profile - it's often sedating at lower doses (15 mg) but may become less sedating at higher doses (30-45 mg).
- It can stimulate appetite and cause weight gain, making it potentially beneficial for patients with depression who have insomnia or weight loss.
- Common side effects include drowsiness, increased appetite, weight gain, and dry mouth. Although mirtazapine is not FDA-approved for insomnia, it is sometimes used off-label for this indication, particularly at lower doses, due to its sedating effects 1. Improvement in sleep and appetite may occur within the first few weeks, while full antidepressant effects typically take 4-6 weeks to develop.
- Patients should avoid alcohol while taking mirtazapine and should not stop the medication abruptly without medical supervision. It's essential to weigh the benefits and risks of mirtazapine, considering its potential for increased appetite and weight gain, as well as its sedating effects, which may be beneficial for patients with insomnia but require caution in other cases 1.
From the FDA Drug Label
Mirtazapine tablets are indicated for the treatment of major depressive disorder (MDD) in adults [see Clinical Studies (14)]. The use of Mirtazapine (Remeron) is for the treatment of major depressive disorder (MDD) in adults 2.
- Indication: Major depressive disorder (MDD)
- Population: Adults
From the Research
Overview of Mirtazapine (Remeron)
Mirtazapine, also known as Remeron, is an antidepressant medication that has been evaluated for its efficacy, safety, and tolerability in the treatment of major depression 3, 4, 5, 6, 7.
Mechanism of Action
Mirtazapine works by blocking presynaptic alpha 2-adrenergic receptors and postsynaptic serotonin type 2 and type 3 receptors, which leads to an increase in noradrenergic and serotonergic activity 3, 6. This unique mechanism of action is thought to be responsible for its rapid onset of action and its ability to improve symptoms of depression, anxiety, and sleep disturbance 4, 5, 7.
Clinical Efficacy
Studies have shown that mirtazapine is effective in the treatment of moderate to severe major depression, with efficacy comparable to that of tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs) 3, 4, 5, 7. Mirtazapine has also been shown to be effective in patients with depression comorbid with anxiety symptoms and sleep disturbance 4, 5, 7.
Adverse Effects
The most common adverse effects associated with mirtazapine are somnolence, increased appetite, weight gain, and dizziness 3, 6. Mirtazapine has a unique tolerability profile, with a lower incidence of anticholinergic events, tremor, and dyspepsia compared to tricyclic antidepressants, and a lower incidence of sexual dysfunction compared to SSRIs 4, 6, 7.
Dosage and Administration
Mirtazapine is typically administered in a single dose at bedtime, with a recommended starting dosage of 15 mg/day 3, 6. The drug is rapidly and completely absorbed after oral administration, and its elimination half-life of 20-40 hours enables once-daily dosing 6, 7.
Key Benefits
- Effective in the treatment of moderate to severe major depression
- Rapid onset of action
- Improves symptoms of anxiety and sleep disturbance
- Unique tolerability profile with a lower incidence of certain adverse effects
- Can be used as a first-line therapy or as an alternative to other antidepressants 3, 4, 5, 6, 7