Mirtazapine
Also known as: Remeron, Mirtaz, Mirt
Important: This is informational content only. Always consult Dr. Ambrish Singal or your psychiatrist before starting, stopping, or changing any medication.
What is Mirtazapine?
Mirtazapine is a unique antidepressant that works by enhancing both norepinephrine and serotonin release. Its sedating and appetite-stimulating properties make it particularly useful for patients with insomnia and weight loss.
How It Works
Blocks alpha-2 adrenergic autoreceptors (increasing norepinephrine/serotonin release), 5-HT2 and 5-HT3 receptors, and histamine H1 receptors. The histamine blockade causes sedation and weight gain.
Uses
How This Drug Starts Working
Effects typically begin within 1-4 weeks depending on the condition being treated. Full therapeutic effect usually takes 4-8 weeks.
Week-by-Week Timeline
Week 1: Medication reaching therapeutic blood levels. Some initial side effects may appear as body adjusts.
Week 2-3: Initial therapeutic effects beginning. Side effects often settling.
Week 4-6: Significant therapeutic benefit in most patients.
Week 8+: Full effect established. Treatment response can be properly assessed.
What Changes First?
Physical symptoms (sleep, appetite, energy) typically improve before emotional and cognitive symptoms. Others may notice improvement before you feel it yourself.
Why Does It Take Time?
Psychiatric medications work by gradually rebalancing brain chemistry and neural circuits. Unlike pain medications that block a sensation, these drugs help your brain rebuild healthy patterns — which requires time.
Complete Dosage Guide
How to Take
Take exactly as prescribed by your doctor. Maintain consistent timing each day.
Starting Dose
Your doctor will determine the appropriate starting dose based on your condition, age, weight, and other factors.
Dose Increases
Dose adjustments are made gradually based on your response and side effects. Follow your doctor's instructions for any changes.
Maximum Dose
Your doctor will not exceed safe maximum doses. Never take more than prescribed.
When to Take
Take at the same time daily for best results. Ask your doctor whether morning or evening is better for your specific medication.
If You Miss a Dose
If you miss a dose, take it as soon as you remember unless close to your next dose. Never double up. Contact your doctor if you miss multiple doses.
Food & Drink
Ask your doctor or pharmacist about specific food interactions for your medication.
How Long to Take
Duration of treatment varies by condition. Never stop medication without discussing with your doctor first — some medications require gradual tapering.
Dosage by Age Group
adult
Start 15mg at bedtime. Increase by 15mg every 1-2 weeks. Usual: 15-45mg/day. Paradoxically, lower doses are more sedating.
child
Not approved for children. Sometimes used off-label in adolescents.
elderly
Start 7.5mg at bedtime. Increase slowly. Effective for depression with insomnia in elderly.
Special Populations
Pregnancy
Category C. Limited data. Generally considered relatively safe but discuss with doctor.
Kidney Conditions
Reduce dose if CrCl < 40 mL/min.
Liver Conditions
Reduce dose in hepatic impairment. Clearance reduced by 30%.
Side Effects
Common
- Sedation/drowsiness
- Increased appetite
- Weight gain
- Dry mouth
- Dizziness
- Constipation
- Elevated cholesterol
Serious
- Agranulocytosis (rare)
- Serotonin syndrome
- Suicidal ideation
- Stevens-Johnson Syndrome (rare)
- Restless leg syndrome
What You Should Know
Overdose Risks
Generally safe in overdose. May cause sedation, disorientation, and tachycardia. Fatalities are extremely rare with mirtazapine alone.
Safe Discontinuation
Taper over 2-4 weeks. Withdrawal symptoms include nausea, dizziness, insomnia, and anxiety. Less severe than SSRI/SNRI discontinuation.