What is the recommended dosage and administration schedule of polysaccharide‑iron complex for a typical adult?

Polysaccharide Iron Complex Dosing for Adults

Critical Limitation: Insufficient Evidence for Polysaccharide Iron Complex

Polysaccharide iron complex is not recommended as a first-line oral iron supplement for adults with iron deficiency anemia because there is no high-quality evidence supporting its efficacy, safety profile, or optimal dosing compared to standard ferrous salts. 1, 2

Recommended Alternative: Standard Ferrous Salts

First-Line Treatment

• Ferrous sulfate 200 mg (providing 65 mg elemental iron) taken once daily in the morning on an empty stomach is the evidence-based standard for treating iron deficiency anemia in adults. 1, 2
• Ferrous sulfate costs approximately £1.00 per 28-day supply, making it the most cost-effective option available. 1, 2
• No oral iron formulation has demonstrated superiority in efficacy or tolerability over ferrous sulfate. 2

Optimal Dosing Strategy

• Once-daily dosing of 50-100 mg elemental iron is superior to multiple daily doses because doses ≥60 mg trigger hepcidin elevation that persists for 24 hours and blocks absorption of subsequent doses by 35-45%. 1, 3, 4
• Iron should be taken 1-2 hours before or after meals to maximize absorption. 1
• Co-administration with 250-500 mg vitamin C (or citrus juice) enhances absorption by forming a chelate with iron. 1, 5

Alternate-Day Dosing for Improved Tolerability

• If daily dosing causes intolerable gastrointestinal side effects, alternate-day dosing (every other day) with 100-200 mg elemental iron significantly increases fractional iron absorption while reducing side effects. 1, 3, 4
• In iron-depleted women, alternate-day dosing resulted in 21.8% fractional absorption versus 16.3% with consecutive daily dosing (p=0.0013). 4

Alternative Ferrous Salts

• Ferrous fumarate (69-106 mg elemental iron per tablet) or ferrous gluconate (35-38 mg elemental iron per tablet) may be substituted if ferrous sulfate is not tolerated, though evidence does not support improved tolerability. 1, 2

Monitoring Response

• Check hemoglobin at 2 weeks; failure to achieve at least a 10 g/L rise strongly predicts treatment failure (sensitivity 90.1%, specificity 79.3%). 1, 2
• Continue treatment for approximately 3 months after hemoglobin normalizes to adequately replenish iron stores. 1, 2

When to Escalate to Intravenous Iron

• Consider intravenous iron if oral iron causes intolerable gastrointestinal symptoms despite dosing adjustments, or if hemoglobin fails to rise after 2-4 weeks of adherent oral therapy. 1, 2
• Modern IV formulations (ferric carboxymaltose, ferric derisomaltose) can replenish total body iron stores in one or two infusions and produce clinically meaningful hemoglobin response within one week. 6, 2

Critical Pitfalls to Avoid

• Do not prescribe multiple daily doses of iron, as this decreases total absorption due to hepcidin elevation and increases gastrointestinal side effects without improving efficacy. 1, 3, 4
• Do not use modified-release iron preparations, as they are classified as "less suitable for prescribing" by the British National Formulary because they release iron beyond the duodenum where absorption is optimal. 1, 2
• Do not rely on multivitamin preparations containing ≤14 mg elemental iron, as these are insufficient for treating iron deficiency anemia. 2

Why Polysaccharide Iron Complex Is Not Recommended

• The available research on polysaccharide iron complex consists only of small comparative studies and laboratory characterization studies, with no high-quality clinical trials establishing optimal dosing, efficacy, or safety in adults. 7, 8
• One small Taiwanese study (n=72) compared a ferrous fumarate combination product to a polysaccharide iron complex and found the ferrous product significantly more effective for increasing hemoglobin and serum ferritin. 7
• Standard ferrous salts remain the evidence-based first-line treatment with established efficacy, safety, and cost-effectiveness. 1, 2