What is the recommended dosage and treatment protocol for Mirtazipine (Mirtazapine) in patients with major depressive disorder?

From the Guidelines

Mirtazapine is typically started at 15 mg once daily at bedtime for adults with major depressive disorder, with gradual increases as needed to an effective dose of 15-45 mg daily. Most patients respond to doses between 15-30 mg daily, though some may require the maximum recommended dose of 45 mg. Elderly patients and those with renal or hepatic impairment should start at 7.5 mg nightly with slower titration. Treatment should continue for at least 6-12 months after symptom resolution to prevent relapse, with discontinuation involving gradual tapering to minimize withdrawal symptoms. Mirtazapine works through multiple mechanisms, including antagonism of alpha-2 adrenergic receptors and serotonin receptors (5-HT2 and 5-HT3), which contributes to its antidepressant and anxiolytic effects. The medication is typically taken at night due to its sedative properties, which can help patients with sleep disturbances. Common side effects include increased appetite, weight gain, sedation, and dry mouth, with sedation often decreasing at higher doses due to the medication's unique pharmacological profile.

Some key points to consider when prescribing mirtazapine include:

• Monitoring patient status, therapeutic response, and adverse effects of antidepressant therapy on a regular basis beginning within 1 to 2 weeks of initiation of therapy 1
• Modifying treatment if the patient does not have an adequate response to pharmacotherapy within 6 to 8 weeks of the initiation of therapy for major depressive disorder 1
• Continuing treatment for 4 to 9 months after a satisfactory response in patients with a first episode of major depressive disorder, with longer durations for patients with recurrent episodes 1
• Selecting between either cognitive behavioral therapy or second-generation antidepressants to treat patients with major depressive disorder after discussing treatment effects, adverse effect profiles, cost, accessibility, and preferences with the patient 1

It's also important to note that the American College of Physicians recommends that clinicians choose pharmacologic therapy to treat patients with acute major depression, selecting second-generation antidepressants on the basis of adverse effect profiles, cost, and patient preferences 1.

Overall, mirtazapine is a viable treatment option for patients with major depressive disorder, with a unique pharmacological profile and potential benefits for patients with sleep disturbances. However, treatment should be individualized and monitored closely to minimize adverse effects and optimize therapeutic response.

From the FDA Drug Label

2.1 Recommended Dosage The recommended starting dose of mirtazapine tablets is 15 mg once daily, administered orally, preferably in the evening prior to sleep. If patients do not have an adequate response to the initial 15 mg dose, increase the dose up to a maximum of 45 mg per day Dose changes should not be made in intervals of less than 1 to 2 weeks to allow sufficient time for evaluation of response to a given dose The recommended dosage and treatment protocol for Mirtazapine in patients with major depressive disorder is to start with 15 mg once daily, preferably in the evening, and increase the dose up to a maximum of 45 mg per day if necessary.

• The dose should be increased in intervals of at least 1 to 2 weeks to allow for evaluation of response.
• It is also important to screen for bipolar disorder prior to starting Mirtazapine tablets 2.

From the Research

Dosage and Treatment Protocol

• The recommended starting dosage of Mirtazapine is 15 mg/day for 4 days, then 30 mg/day for 10 days 3.
• If effective, the drug should be continued unchanged at this dosage or, in patients assessed as insufficiently improved, the daily dosage may be further increased to 45 mg/day 3.
• The recommended initial dosage is 15 mg once/day at bedtime, with an effective daily dosage range of 15-45 mg 4, 5.
• Monotherapy with Mirtazapine 15-45 mg/day leads to rapid and sustained improvements in depressive symptoms in patients with major depression 6.

Administration and Pharmacokinetics

• Mirtazapine is rapidly and completely absorbed after oral administration 5.
• It is biotransformed by hepatic demethylation and is suitable for once-daily doses 5.
• The elimination half-life of Mirtazapine is approximately 20-40 hours, enabling once-daily bedtime dosing 4, 7.

Efficacy and Safety

• Mirtazapine has been shown to be equally efficacious as amitriptyline, clomipramine, and doxepin as assessed by scores on the HAM-D or other depression rating scales 3, 5.
• It appears to have a broad spectrum of activity, reflected in its efficacy in a variety of clinical settings 7.
• Mirtazapine has demonstrated superior tolerability to the tricyclic antidepressants and trazodone, primarily on account of its relative absence of anticholinergic, adrenergic and serotonin-related adverse effects 3, 7.
• The most commonly reported adverse effects associated with Mirtazapine are somnolence, increased appetite, weight gain, and dizziness 5.