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MEDICINE MONOGRAPH CODE: [11.21] ID: TIP-MED-000225

Mirtazapine (NaSSA Antidepressant & Appetite/Sleep Aid)

Active Ingredient / Scientific Identity: Mirtazapine • Class: Noradrenergic and Specific Serotonergic Antidepressant (NaSSA; Central Alpha-2 Antagonist)

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THE INDIAN PHARMACIST — Educational Reference Sheet
Profile: Mirtazapine (NaSSA Antidepressant & Appetite/Sleep Aid) ([11.21] | ID: TIP-MED-000225) • Last Reviewed: 2026-11-10
Source URL: https://theindianpharmacist.com/medicine/11-21-mirtazapine-nassa-antidepressant-appetite-sleep-aid/
Generic / Entity NameMirtazapine (NaSSA Antidepressant & Appetite/Sleep Aid) ([11.21])
Verified Indian Brands / RefGeneric Compendial Entry (No Commercial Brand Claimed)
Pharmacological ClassNoradrenergic and Specific Serotonergic Antidepressant (NaSSA; Central Alpha-2 Antagonist)
Available Dosage FormsFilm-Coated Tablet / Orally Disintegrating Tablet (ODT): 7.5 mg, 15 mg, 30 mg, 45 mg.
Regulatory ClassificationSchedule H Prescription Drug (To be sold by retail on the prescription of a Registere
Key Warning & Review DateRenal: eGFR 15-30 mL/min: Clearance reduced by 30%; eGFR <15 mL/min: Clearance reduced by 50%; titrate cautiously. • Hepatic:
Reviewed: 2026-11-10
Safety Matrix:⚖️ Legal Status: Schedule H Prescription Drug (To be sold by retail o✔️ Standard Clinical Dispensing Precautions

1. Clinical & Scientific Overview

Mirtazapine (NaSSA Antidepressant & Appetite/Sleep Aid) (TIP-MED-000225, Reference Code [11.21]) is classified under CNS & Psychiatric Medicines (Ch 11) as a Noradrenergic and Specific Serotonergic Antidepressant (NaSSA; Central Alpha-2 Antagonist). Within the Indian regulatory and compendial framework, it is governed under Schedule H Prescription Drug (To be sold by retail on the prescription of a Registered Medical Practitioner only — Drugs Rules 1945).

Verified Indian Market Examples / Compendial Status:
Representative Indian Market Examples (Edition 2.7 Ch 11 [11.21], p. 150): Mirnite, Mirtaz, Nassa, Mirtafresh — Strengths & Dosage Forms: Film-Coated Tablet / Orally Disintegrating Tablet (ODT): 7.5 mg, 15 mg, 30 mg, 45 mg.
Representative Indian Market Examples (Edition 2.7 Ch 11 [11.21], p. 150): Mirnite, Mirtaz, Nassa, Mirtafresh — Strengths & Dosage Forms: Film-Coated Tablet / Orally Disintegrating Tablet (ODT): 7.5 mg, 15 mg, 30 mg, 45 mg.
Dosage Forms & Available Strengths:
Film-Coated Tablet / Orally Disintegrating Tablet (ODT): 7.5 mg, 15 mg, 30 mg, 45 mg.
Routes: Oral / Parenteral / Topical as specified by formulation

3. Mechanism of Action & Pharmacodynamics

Blocks central presynaptic alpha-2 adrenergic auto- and heteroreceptors -> increases noradrenergic and 5-HT1A serotonergic transmission while blocking post-synaptic 5-HT2A, 5-HT2C, 5-HT3 (antiemetic), and H1 histamine receptors.

4. Therapeutic Indications & Evidence-Supported Uses

  • Major depressive disorder (especially with severe insomnia, anxiety, weight loss, or chemotherapy/GI nausea)

🇮🇳 Jurisdiction & Indication Note: Indications and schedules reflect Indian compendial and regulatory records (CDSCO / Indian Pharmacopoeia & NFI / NLEM 2022). Where international reference labels (US FDA DailyMed / NCBI StatPearls) are cited for pharmacokinetic or mechanistic parameters, international approvals do not automatically imply CDSCO approval in India.

5. Educational Dosage Context, Formulations & Administration

Educational Dosing & Regimen Summary: Adult: Start 15 mg PO once daily at bedtime; titrate every 1-2 weeks to effective antidepressant dose of 30-45 mg at bedtime. • Paediatric: Not recommended in children <18 years.

Administration & Meal Timing: See Administration & Counselling below. | Standard clinical schedule per indication.

6. Pharmacokinetics, Metabolism & Renal/Hepatic Adjustment

Absorption & Disposition:
Absorption, distribution, metabolism, and excretion follow class pharmacokinetic profile; verify patient renal/hepatic function.
Metabolism & Biotransformation:
Renal: eGFR 15-30 mL/min: Clearance reduced by 30%; eGFR <15 mL/min: Clearance reduced by 50%; titrate cautiously. • Hepatic: Mild-to-moderate hepatic impairment: Clearance reduced by ~30%; use lower maintenance dose.
Elimination & Renal Adjustment:
Renal: eGFR 15-30 mL/min: Clearance reduced by 30%; eGFR <15 mL/min: Clearance reduced by 50%; titrate cautiously. • Hepatic: Mild-to-moderate hepatic impairment: Clearance reduced by ~30%; use lower maintenance dose.
Hepatic Impairment Considerations:
Renal: eGFR 15-30 mL/min: Clearance reduced by 30%; eGFR <15 mL/min: Clearance reduced by 50%; titrate cautiously. • Hepatic: Mild-to-moderate hepatic impairment: Clearance reduced by ~30%; use lower maintenance dose.

7. Contraindications, Precautions & High-Risk Warnings

Contraindications & Red-Flag Precautions:
  • Contraindications: Concomitant MAOIs or Linezolid (within 14 days). • Precautions: Paradoxical dose-sedation relationship: lower doses (7.5-15 mg) are MORE sedating than higher doses (30-45 mg) because H1 antihistamine effect predominates at low doses while activating noradrenergic release offsets sedation at >=30 mg.

Key Clinical Precautions: Renal: eGFR 15-30 mL/min: Clearance reduced by 30%; eGFR <15 mL/min: Clearance reduced by 50%; titrate cautiously. • Hepatic: Mild-to-moderate hepatic impairment: Clearance reduced by ~30%; use lower maintenance dose.

8. Adverse Effects Profile

Common & Mechanism-Related Adverse Effects:
  • Marked somnolence, increased appetite, weight gain, dry mouth, dizziness.
  • Rare reversible agranulocytosis/neutropenia (presents as fever/sore throat), hypertriglyceridaemia, QT prolongation.
Serious / Dose-Limiting Adverse Effects:
  • Monitor for severe hypersensitivity, organ toxicity, or dose-limiting adverse events.

9. Major Drug–Drug, Drug–Food & Drug–Herb Interactions

  • Alcohol / Benzodiazepines -> additive sedation; CYP3A4 inhibitors (Ketoconazole) -> increase levels; Phenytoin / Carbamazepine -> reduce mirtazapine levels by 50%

10. Clinical Monitoring, Patient Counselling & Storage

Clinical & Laboratory Monitoring: Monitor clinical response, baseline renal/hepatic parameters, and relevant serum biomarkers.

Pharmacist Patient Counselling Points:

  • Patient Counselling Checklist: Take at bedtime; low doses cause strong sleepiness; report any unexplained fever, sore throat, or mouth ulcers immediately.
  • Meal & Clock Timing Instruction: See Administration & Counselling below. (Standard clinical schedule per indication.)
  • Missed Dose Protocol: Take as soon as remembered unless close to next scheduled dose; never double the dose.
  • Geriatric Dispensing Pearl: Schedule: Schedule H | NLEM 2022: Non-NLEM | Compendia: IP 2026 / NFI 7th Ed 2026 / CDSCO Schedule H / BNF 90th Ed

Storage, Stability & Dispensing Safeguards: Store below 25°C–30°C in original moisture- and light-resistant packaging out of reach of children. Available forms: Film-Coated Tablet / Orally Disintegrating Tablet (ODT): 7.5 mg, 15 mg, 30 mg, 45 mg.

11. Visual Pharmacology & Mechanism Diagram (svg-v339-01-adme-12-step-journey)

THE 12-STEP ORAL DRUG JOURNEY THROUGH THE HUMAN BODY (LADME) Note: IV bolus enters Step 6 directly (F = 100%); Sublingual & Transdermal routes bypass Step 4–5 Portal First-Pass Metabolism 1. Oral Administration • Tablet / Capsule swallowed • Gastric emptying to duodenum pH 1.5–3.5 (Stomach) 2. Disintegration & Dissolution • Tablet breaks into granules • API dissolves in GI fluid Noyes-Whitney Dissolution Rate 3. GI Epithelial Absorption • Crosses intestinal villi • Passive / Active / P-gp efflux Small Intestine (Large Surface Area) 4. Portal Circulation • Mesenteric veins → Portal vein • Delivers blood to liver sinusoids Pre-systemic Venous Conduit 5. First-Pass Metabolism • Gut & hepatic CYP450 extraction • High: GTN, Propranolol, Morphine Determines Bioavailability (F = f_a × (1-E_H)) 6. Systemic Circulation • Hepatic vein → IVC → Heart • Unbound vs Albumin-bound drug Only FREE drug is active 7–8. Tissue Distribution (Vd) • Capillary permeation to organs • Blood-Brain & Placental barriers Vd = Dose / C_0 (L or L/kg) 9. Target Site of Action • Receptors (GPCR, Ion channel) • Enzymes & Carrier Transporters Pharmacodynamic Effect (E_max, EC50) 10. Hepatic Biotransformation • Phase I (CYP450 Oxidation/Hydrolysis) • Phase II (Glucuronidation/Sulfation) Converts lipophilic drug → hydrophilic metabolite 11. Renal & Biliary Elimination • Nephron: Filtration + Secretion − Reabsorption • Biliary excretion & Enterohepatic recycling Total Clearance CL_tot = CL_renal + CL_hepatic 12. Excretion from the Body • Urine (Primary polar metabolite route) • Bile/Faeces, Expired Air, Sweat, Milk Elimination Half-Life t1/2 = (0.693 × Vd) / CL
svg-v339-01-adme-12-step-journey — 8.1 Complete 12-Step Journey of an Orally Administered Drug (ADME): Figure 8.1: The 12-step physiological journey of a typical orally administered solid dosage form through Liberation, Absorption, Distribution, Metabolism, and Excretion (LADME). Note: Parenteral (IV), sublingual, and inhalational routes bypass gastrointestinal absorption and/or hepatic first-pass metabolism.

12. Authoritative References, Regulatory Sources & Editorial Disclaimer

Primary Compendial & Guideline Reference: Indian Pharmacist Desk Reference — Professional Edition 2.7 (2026–27) • Ch 11 [11.21] (p. 150)

Official Verification Portals: Indian Pharmacopoeia Commission (IPC) & National Formulary of India (NFI) • Central Drugs Standard Control Organization (CDSCO) • Ministry of Health & Family Welfare — NLEM 2022 • NCBI Bookshelf / StatPearls Pharmacology Reference • DailyMed (US FDA Official Prescribing Reference)

Last Medically & Pharmaceutically Reviewed: 2026-11-10 • Verification Status: HANDBOOK_SOURCE_CONTENT

Educational & Clinical Disclaimer: This reference profile is published solely for pharmacy education, academic study, and professional clinical reference. It does not substitute for patient-specific clinical judgement, qualified specialist oncology/medical supervision, or official CDSCO/IP prescribing information. Never self-medicate with prescription, Schedule H/H1/X, NDPS, or oncology medicines.

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Educational Reference Notice: This printout from THE INDIAN PHARMACIST (https://theindianpharmacist.com/medicine/11-21-mirtazapine-nassa-antidepressant-appetite-sleep-aid/, Last Reviewed: 2026-11-10) is an educational reference sheet for students and healthcare learners. It is NOT an official prescribing guideline or patient-specific treatment order.