Safely Increasing Mirtazapine (Remeron) Dosage from 15mg
When increasing mirtazapine from 15mg, increase the dose to 30mg once daily, preferably in the evening prior to sleep, and wait 1-2 weeks before considering any further increase to the maximum dose of 45mg. 1
Dosing Protocol for Mirtazapine Increase
Initial Increase (15mg to 30mg)
- Increase from 15mg to 30mg once daily, taken in the evening before sleep 1
- Allow 1-2 weeks at the new dose to properly evaluate response before considering further increases 1
- Take with or without food (food has minimal effect on absorption) 2
Further Increase (if needed)
- If insufficient response after 1-2 weeks at 30mg, may increase to maximum dose of 45mg once daily 1
- Maximum recommended dose is 45mg daily 1
- Therapeutic plasma concentrations typically range from 5 to 100 μg/L at doses of 15-45mg daily 2
Monitoring After Dose Increase
Short-term Monitoring (first 1-2 weeks)
- Monitor for increased sedation, which is dose-dependent and most common during initial titration 3
- Watch for increased appetite and potential weight gain (10% of patients experience weight gain) 4
- Assess for dry mouth (25% of patients) and excessive sedation (19% of patients) 4
Long-term Monitoring
- Evaluate therapeutic response after 4-8 weeks (full therapeutic trial duration) 3
- Monitor for continued side effects, particularly weight gain and sedation
- Assess for improvement in both depressive symptoms and sleep quality
Clinical Considerations
Pharmacological Properties
- Mirtazapine has a half-life of 20-40 hours, making once-daily dosing appropriate 5
- Steady state is reached after 4-6 days of consistent dosing 2
- Mirtazapine shows linear pharmacokinetics over the dose range of 15-80mg 2
Special Populations
- For elderly patients or those with hepatic/renal impairment, more careful titration is recommended 2
- Women and elderly patients typically have higher plasma concentrations than men and younger adults 2
- Liver and moderate renal impairment cause approximately 30% decrease in mirtazapine clearance 2
Drug Interactions
- Adjust dosing if patient is taking strong CYP3A inducers (e.g., carbamazepine, phenytoin, rifampin) or inhibitors 1
- With strong CYP3A inducers: may need higher mirtazapine dose
- With strong CYP3A inhibitors (e.g., ketoconazole, clarithromycin): may need lower mirtazapine dose
Common Pitfalls to Avoid
- Increasing dose too rapidly: Always wait 1-2 weeks between dose adjustments 1
- Discontinuing abruptly: If needing to stop, gradually reduce the dose to avoid withdrawal symptoms 1
- Missing the therapeutic window: Lower doses (7.5-15mg) may be more sedating than higher doses due to the predominance of H1 receptor antagonism at lower doses 5
- Ignoring daytime sedation: Consider taking the dose earlier in the evening if morning sedation is problematic
- Overlooking weight gain: Monitor weight regularly as increased appetite is a common side effect 3
Mirtazapine is generally well tolerated and has a favorable safety profile with minimal cardiovascular effects, anticholinergic effects, and sexual dysfunction compared to other antidepressants 5.