Mirtazapine Brand Names and Dosing Instructions
Mirtazapine is marketed under the brand name Remeron, with generic formulations widely available, and should be initiated at 15 mg once daily at bedtime, with dosing adjustments made based on clinical response. 1
Available Formulations
Mirtazapine tablets are supplied in three strengths 1:
- 15 mg tablets: Pale yellow, oval-shaped, scored, film-coated
- 30 mg tablets: Light pink, oval-shaped, scored, film-coated
- 45 mg tablets: White to off-white, oval-shaped, unscored, film-coated
Dosing Recommendations
Standard Dosing for Depression
The recommended starting dosage is 15 mg once daily at bedtime 2. The effective dosage range is 15-45 mg per day 3, 4.
Dosage titration should follow this approach 2:
- Start with 7.5-15 mg at bedtime
- Increase to 30 mg after 4-10 days if tolerated
- May further increase to maximum 45 mg daily if insufficient response after assessment
Special Populations
For elderly or debilitated patients: Consider starting at 7.5 mg at bedtime, with careful upward titration 2. Mirtazapine is considered a preferred agent for older adults with depression due to its favorable adverse effect profile 3.
For patients with hepatic or renal impairment: Careful dosage titration with regular monitoring is recommended, as dose reduction may be necessary 3, 1.
Administration Instructions
- Take once daily at bedtime to maximize the sedating effects and minimize daytime somnolence 2
- Can be taken with or without food
- Scored tablets (15 mg and 30 mg) may be split if needed; the 45 mg tablet is unscored and should be swallowed whole 1
- Store at room temperature (20°C to 25°C), protected from light and moisture 1
Clinical Monitoring
Assess patient status, therapeutic response, and adverse effects within 1-2 weeks of initiation 4. Continue regular monitoring throughout treatment.
Modify treatment if inadequate response after 6-8 weeks 4. A full therapeutic trial requires at least 4-8 weeks, though sleep disturbances and anxiety may improve within the first week 5.
Duration of Treatment
Continue treatment for 4-9 months after satisfactory response for a first episode of major depression 3, 4. For patients with recurrent depression (≥2 episodes), longer duration therapy is beneficial 3, 4.
When discontinuing, taper over 10-14 days to limit withdrawal symptoms 2.
Common Adverse Effects
The most frequently reported side effects include 6, 2, 7:
- Somnolence (tends to be less frequent at higher dosages)
- Increased appetite and weight gain (related to antihistaminic effects at low doses)
- Dry mouth
- Dizziness
Important note: Mirtazapine is associated with weight gain as a side effect, which may be beneficial in patients with depression and poor appetite, but should be monitored 8, 2.
Key Clinical Considerations
Mirtazapine's unique mechanism—blocking presynaptic α2-adrenergic receptors and postsynaptic 5-HT2 and 5-HT3 receptors—provides antidepressant efficacy with minimal anticholinergic, cardiovascular, and sexual side effects compared to tricyclic antidepressants and SSRIs 6, 7, 5.
The drug is particularly useful for patients with 6:
- Comorbid insomnia (sedating properties)
- Comorbid anxiety (anxiolytic effects)
- Poor appetite or weight loss (appetite-stimulating effects)