1. Clinical & Scientific Overview
Magnesium Hydroxide (TIP-MED-000292, Reference Code [5.12]-C22) is classified under
Gastrointestinal & Hepatobiliary Medicines (Ch 05) as a Local Gastric Acid Neutralisers (Non-Systemic Antacids) with Antiflatulent (Simethicone) or Mucosal Anaesthetic (Oxetacaine).
Within the Indian regulatory and compendial framework, it is governed under Non-Schedule / OTC or Schedule K Permitted Preparation (Medical Supervision Recommended for High-Dose/Therapeutic Regimens).
Co-indexed constituent under primary monograph [5.12] (Antacids (Aluminium Hydroxide + Magnesium Hydroxide + Simethicone / Magaldrate / Oxetacaine Combinations)). Representative Indian Market Examples (Edition 2.7 Ch 05 [5.12], p. 65): Digene Gel / Tablets (Abbott), Gelusil MPS (Pfizer), Mucaine Gel (Pfizer—contains Oxetacaine), Siloxogene, Polycrol, Aciloc-RD/Antacid syrups — Strengths & Dosage Forms: Chewable Tablets & Oral Suspensions (typically 5–10 mL containing Al(OH)3 200–400 mg + Mg(OH)2 100–400 mg or Magaldrate 400–540 mg + Simethicone 20–50 mg ± Oxetacaine 10 mg/5 mL)
Chewable Tablets & Oral Suspensions (typically 5–10 mL containing Al(OH)3 200–400 mg + Mg(OH)2 100–400 mg or Magaldrate 400–540 mg + Simethicone 20–50 mg ± Oxetacaine 10 mg/5 mL)
3. Mechanism of Action & Pharmacodynamics
Local Gastric Acid Neutralisers (Non-Systemic Antacids) with Antiflatulent (Simethicone) or Mucosal Anaesthetic (Oxetacaine) acting on target receptor/enzyme pathways in Gastrointestinal & Hepatobiliary Medicines (Ch 05): clinical efficacy is mediated via Local Gastric Acid Neutralisers (Non-Systemic Antacids) with Antiflatulent (Simethicone) or Mucosal Anaesthetic (Oxetacaine) for Rapid symptomatic relief of acute hyperacidity, heartburn, acid indigestion, sour eructation, and bloating/flatulence..
4. Therapeutic Indications & Evidence-Supported Uses
- Rapid symptomatic relief of acute hyperacidity, heartburn, acid indigestion, sour eructation, and bloating/flatulence
🇮🇳 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: General Adult Reference: 10 mL to 15 mL suspension (or 2 chewable tablets, chewed thoroughly) 3 to 4 times daily as needed (SOS), taken 1 hour AFTER meals and at bedtime. Follow physician prescription.
Administration & Meal Timing: Take 1 hour AFTER meals and at bedtime (if taken on an empty stomach, antacids empty into the duodenum within 20–30 minutes; when taken 1 hour after a meal, food buffers and slows gastric emptying, extending acid neutralisation to 2–3 hours!). | 1 hour after breakfast, lunch, and dinner, and at bedtime (or SOS for acute heartburn).
6. Pharmacokinetics, Metabolism & Renal/Hepatic Adjustment
Follows class pharmacokinetic profile detailed in parent monograph [5.12].
Renal: Strictly avoid chronic Mg/Al antacids if eGFR <30 mL/min! Hepatic: Avoid high-sodium effervescent antacids in cirrhotic ascites.
Renal: Strictly avoid chronic Mg/Al antacids if eGFR <30 mL/min! Hepatic: Avoid high-sodium effervescent antacids in cirrhotic ascites.
Renal: Strictly avoid chronic Mg/Al antacids if eGFR <30 mL/min! Hepatic: Avoid high-sodium effervescent antacids in cirrhotic ascites.
7. Contraindications, Precautions & High-Risk Warnings
- Avoid Magnesium- and Aluminium-containing antacids in severe Chronic Kidney Disease (eGFR <30 mL/min) due to risk of fatal hypermagnesaemia and aluminium toxicity. Check sodium content in alginate/bicarbonate preparations (e.g., Gaviscon/Eno) in patients with heart failure, cirrhosis, or severe hypertension.
Key Clinical Precautions: Renal: Strictly avoid chronic Mg/Al antacids if eGFR <30 mL/min! Hepatic: Avoid high-sodium effervescent antacids in cirrhotic ascites.
8. Adverse Effects Profile
- Magnesium hydroxide causes osmotic loose stools/diarrhoea; Aluminium hydroxide causes constipation (combined Al+Mg formulations balance bowel effects, though mild diarrhoea or constipation may still occur), chalky taste, oral numbness (with Mucaine/oxetacaine).
- Hypermagnesaemia (areflexia, respiratory depression, heart block) and aluminium neurotoxicity/osteomalacia in CKD, hypophosphataemia (aluminium binds dietary phosphate in the gut with chronic excess use).
9. Major Drug–Drug, Drug–Food & Drug–Herb Interactions
- Universal Chelation & pH Interaction Alert: Antacids chelate or alter the pH-dependent dissolution of Fluoroquinolones (ciprofloxacin, levofloxacin), Tetracyclines (doxycycline), Oral Iron, Levothyroxine, Bisphosphonates, Itraconazole, Ketoconazole, Cefuroxime, Cefpodoxime, Rosuvastatin, Gabapentin, Digoxin, and Enteric-Coated Tablets (Bisacodyl, Aspirin EC, PPIs)
- Maintain a strict 2-hour window BEFORE or 2–4 hours AFTER taking any other oral medicine!
10. Clinical Monitoring, Patient Counselling & Storage
Clinical & Laboratory Monitoring: Monitor clinical parameters per parent monograph [5.12].
Pharmacist Patient Counselling Points:
- Patient Counselling Checklist: For chewable tablets (Digene/Gelusil): chew the tablets thoroughly into a fine paste before swallowing and follow with half a glass of water—swallowing whole antacid tablets prevents rapid acid neutralisation. Shake liquid bottles well. Never take an antacid at the same time as your morning BP, thyroid, diabetes, or antibiotic tablets (keep a 2-hour gap).
- Meal & Clock Timing Instruction: Take 1 hour AFTER meals and at bedtime (if taken on an empty stomach, antacids empty into the duodenum within 20–30 minutes; when taken 1 hour after a meal, food buffers and slows gastric emptying, extending acid neutralisation to 2–3 hours!). (1 hour after breakfast, lunch, and dinner, and at bedtime (or SOS for acute heartburn).)
- Missed Dose Protocol: Used SOS for symptom relief; do not double.
- Geriatric Dispensing Pearl: Elderly CGHS patients frequently self-medicate with Digene/Gelusil alongside their morning or night prescription pile, inadvertently chelating their levothyroxine, iron, or ciprofloxacin. Always place antacids in a separate 1-hour post-meal window.
Storage, Stability & Dispensing Safeguards: Store below 25°C–30°C in original moisture- and light-resistant packaging out of reach of children. Available forms: Chewable Tablets & Oral Suspensions (typically 5–10 mL containing Al(OH)3 200–400 mg + Mg(OH)2 100–400 mg or Magaldrate 400–540 mg + Simethicone 20–50 mg ± Oxetacaine 10 mg/5 mL)
11. Visual Pharmacology & Mechanism Diagram (svg-v339-01-adme-12-step-journey)
12. Authoritative References, Regulatory Sources & Editorial Disclaimer
Primary Compendial & Guideline Reference: Indian Pharmacopoeia (IP 2022) • NFI • CDSCO
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: VERIFIED_EDUCATIONAL_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.
13. Related Reference Monographs, Educational Guides & Visual Concept
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