Ferrous Gluconate Dosage
For iron deficiency anemia in adults, ferrous gluconate should be dosed at 50-100 mg of elemental iron once daily, which translates to approximately 2-3 tablets (324 mg each) per day, given that each 324 mg tablet contains 37-38 mg of elemental iron. 1, 2
Standard Adult Dosing
Once-daily dosing of 50-100 mg elemental iron is the evidence-based approach for treating iron deficiency anemia, based on recent understanding that higher frequency dosing increases hepcidin levels and paradoxically reduces iron absorption 1
Ferrous gluconate 324 mg tablets contain 37-38 mg elemental iron per tablet 1, 2
To achieve the recommended 50-100 mg elemental iron daily, prescribe 2-3 tablets of ferrous gluconate 324 mg once daily 1
The FDA label suggests 3-4 tablets daily (providing 114-152 mg elemental iron), but this conflicts with newer evidence showing once-daily dosing is superior 2
Key Dosing Principles
Alternate-day dosing may be considered as an alternative strategy, as it significantly increases fractional iron absorption compared to daily dosing, though the rate of hemoglobin rise is slower 1
Alternate-day dosing with 100-200 mg elemental iron showed higher fractional absorption than daily dosing in iron-depleted women 1
For patients with gastrointestinal side effects, alternate-day dosing provides better tolerability while maintaining efficacy 1
Pediatric Considerations
For infants 4-12 months, ferrous gluconate at prophylactic doses effectively prevents iron deficiency anemia 3, 4
The FDA label recommends consulting a physician for pediatric dosing 2
Important Clinical Caveats
Do not crush or chew tablets as this may affect absorption and increase gastrointestinal side effects 2
Monitor hemoglobin response at 2 weeks - failure to increase hemoglobin by at least 10 g/L strongly predicts treatment failure (sensitivity 90.1%, specificity 79.3%) and should prompt consideration of intravenous iron 1
Ferrous gluconate is better tolerated than ferrous sulfate with fewer gastrointestinal side effects, though it contains less elemental iron per tablet (37-38 mg vs 65 mg) 1, 5, 6
Continue treatment for 3-6 months after hemoglobin normalization to adequately replenish iron stores 1