What is the recommended dosage of Magnex forte (Ferrous sulfate) for an adult patient with iron deficiency anemia?

Magnex Forte Dosage for Iron Deficiency Anemia

For adult patients with iron deficiency anemia, start with one tablet of ferrous sulfate 200 mg (providing 65 mg elemental iron) once daily, taken on an empty stomach. 1

Initial Dosing Strategy

• Begin with 50-100 mg elemental iron once daily rather than multiple daily doses, as this optimizes absorption while minimizing side effects 1, 2
• A standard ferrous sulfate 200 mg tablet contains 65 mg elemental iron and represents the gold standard, most cost-effective option 1, 3
• Take iron on an empty stomach to maximize absorption, though this may increase gastrointestinal side effects 1, 2
• Avoid multiple daily doses: 60 mg elemental iron taken once daily produces similar overall absorption to 60 mg taken twice daily, because hepcidin elevation persists for 24 hours and blocks subsequent iron absorption by 35-45% 1, 4

If Standard Dosing Not Tolerated

• Reduce to one tablet every other day if daily dosing causes intolerable side effects 1
• Alternate-day dosing with 100-200 mg elemental iron actually increases fractional iron absorption compared to daily dosing, though the rate of hemoglobin rise may be slower initially 1, 4
• Consider taking iron with food to reduce side effects, though this decreases absorption 2
• Alternative ferrous salts (ferrous fumarate 210 mg providing 69 mg elemental iron, or ferrous gluconate 300 mg providing 37 mg elemental iron) can be tried, though evidence does not support improved tolerability 1, 4

Monitoring Response

• Check hemoglobin within 4 weeks of starting treatment to assess response 1, 2
• Expect hemoglobin to increase by at least 10 g/L within 2 weeks; failure to achieve this strongly predicts treatment failure (sensitivity 90.1%, specificity 79.3%) 1, 2
• If hemoglobin has not risen by at least 10 g/L at 2 weeks, investigate for non-compliance, continued bleeding, malabsorption, or concurrent vitamin B12/folate deficiency 1, 4

Duration of Treatment

• Continue treatment for approximately 3 months after hemoglobin normalizes to ensure adequate repletion of marrow iron stores 1, 2
• After successful treatment, monitor blood count every 6 months initially to detect recurrent anemia 1

When to Consider Parenteral Iron

• Switch to intravenous iron if oral iron is contraindicated, ineffective, or not tolerated despite dosing modifications 1, 2
• Parenteral iron should be considered when colonoscopy is imminent, as oral iron can interfere with visualization 1
• Intravenous iron produces a clinically meaningful hemoglobin response within one week and can replenish total body iron stores in one or two infusions 4, 3

Common Pitfalls to Avoid

• Do not prescribe modified-release preparations, as they are less suitable for prescribing and offer no proven advantage 1, 4
• Do not rely on multivitamin preparations, which typically contain insufficient elemental iron (up to 14 mg) for treating iron deficiency anemia 1, 4
• Do not prescribe three-times-daily dosing, as this is based on outdated evidence and increases side effects without improving absorption 1, 5
• Avoid taking iron with tea, coffee, or calcium-containing foods/medications, which inhibit absorption 2, 4

Strategies to Enhance Absorption

• Consider taking iron with vitamin C (250-500 mg) or citrus fruits/drinks to enhance absorption 1, 2, 4
• Separate iron and calcium supplements by 1-2 hours to avoid affecting absorption of each 1