What is the recommended dose of ferrous gluconate (iron supplement) for treating iron deficiency anemia?

Ferrous Gluconate Dosing for Iron Deficiency Anemia

For adults with iron deficiency anemia, ferrous gluconate should be dosed at 324 mg tablets (containing 38 mg elemental iron) taken 3-4 times daily, providing approximately 114-152 mg of elemental iron per day, though the total daily elemental iron target is 200 mg in divided doses. 1, 2

Standard Oral Iron Dosing

Adults

• Target dose: 200 mg of elemental iron per day in 2-3 divided doses 2
• Ferrous gluconate specifically: Each 324-325 mg tablet contains only 35-38 mg of elemental iron 2, 1
• To achieve the 200 mg elemental iron target with ferrous gluconate, you would need approximately 5-6 tablets daily (divided into 2-3 doses) 2, 1
• However, ferrous sulfate (65 mg elemental iron per 325 mg tablet) or ferrous fumarate (108 mg elemental iron per 325 mg tablet) are more cost-effective alternatives that require fewer tablets 2

Pediatric Patients

• Target dose: 2-3 mg/kg/day of elemental iron 2
• Consult a physician for specific pediatric dosing with ferrous gluconate 1

Key Administration Principles

Timing and Absorption

• Take on an empty stomach (without food or other medications) for optimal absorption 2
• Food reduces iron absorption by up to 50% if eaten within 2 hours before or 1 hour after the iron supplement 2
• Consider ascorbic acid 250-500 mg twice daily with iron to enhance absorption if response is poor 2

Duration of Treatment

• Continue oral iron for 3 months after correction of anemia to replenish iron stores 2
• Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of treatment 2

When Ferrous Gluconate May Not Be Optimal

Cost and Efficacy Considerations

Ferrous sulfate is the preferred first-line oral iron preparation because it is the cheapest option and provides more elemental iron per tablet 2

• Ferrous gluconate costs approximately $5.08 per month versus $2.29 for ferrous sulfate 2
• All ionic iron salts (sulfate, gluconate, fumarate) are equally effective when equivalent elemental iron doses are given 2

Alternative Dosing Strategy

Lower doses (100 mg elemental iron daily or even alternate-day dosing) may be as effective and better tolerated 2

• Recent evidence suggests once-daily or alternate-day dosing may improve absorption by avoiding hepcidin upregulation 2
• For patients with inflammatory bowel disease specifically, no more than 100 mg elemental iron per day is recommended 2

When to Consider Intravenous Iron

Switch to IV iron if: 2

• Intolerance to at least two different oral iron preparations
• Non-compliance with oral therapy
• Continued blood loss exceeding oral iron absorption capacity
• Malabsorption conditions (celiac disease, inflammatory bowel disease, post-bariatric surgery) 2
• Inadequate response after 3-4 weeks of appropriate oral therapy 2

Common Pitfalls to Avoid

• Don't crush or chew tablets 1
• Don't assume all iron preparations contain the same elemental iron - ferrous gluconate has significantly less elemental iron per tablet than ferrous sulfate or fumarate 2
• Don't continue oral iron indefinitely without monitoring - check hemoglobin and red cell indices at 3-4 weeks, then every 3 months for one year 2
• Don't overlook the underlying cause - failure to respond suggests continued blood loss, malabsorption, misdiagnosis, or poor compliance 2