Iron Sucrose

Iron sucrose is an intravenous iron-carbohydrate complex that delivers iron when oral iron fails or cannot be used. It is supplied as 20 mg/mL elemental iron, and doses here are elemental iron.

Classification. Parenteral iron; iron-carbohydrate complex.

Mechanism. The complex is taken up by the reticuloendothelial system, which releases iron to transferrin for erythropoiesis and storage.

Pharmacokinetics. Distribution volume is about the plasma volume and terminal half-life is about 6 hours. Iron is cleared by the reticuloendothelial system, with minimal renal loss.

Iron deficiency in chronic kidney disease.

• Non-dialysis chronic kidney disease: 200 mg intravenously over 2 to 5 minutes (slow injection) or by infusion on five occasions within 14 days; total 1000 mg.
• Haemodialysis: 100 mg into the dialysis circuit at consecutive sessions, total 1000 mg over 10 sessions.
• Peritoneal dialysis: 300 mg by infusion over 90 minutes twice, 14 days apart, then 400 mg once 14 days later.
• Maximum: 200 mg by injection and 500 mg by infusion in a single dose, not more than three times each week. Loading dose: none.

Iron deficiency anaemia with oral intolerance or failure (adults).

• Dose: 200 mg intravenously, up to three times weekly, until the calculated deficit is given.
• Total iron deficit: weight in kg multiplied by (target haemoglobin minus actual haemoglobin in g/dL) multiplied by 2.4, plus 500 mg for stores in patients over 35 kg.

Children.

• Chronic kidney disease: 0.5 mg/kg (maximum 100 mg) intravenously at dialysis sessions or every 4 weeks, directed by the paediatric nephrology team. Use outside this setting is specialist only.

Adjustments. Kidney: no reduction needed. Liver: avoid in decompensated disease or hepatic iron overload. Weight: dose by deficit calculation.

Contraindications. Iron overload, anaemia not caused by iron deficiency, hypersensitivity to the product, and active serious infection (withhold until controlled).

Adverse effects. Common: taste disturbance, hypotension, nausea, injection-site reactions and venous staining after extravasation. Serious: infusion reactions from complement activation (flushing, chest tightness, back pain) and, rarely, anaphylaxis. Hypophosphataemia is uncommon with this agent.

Interactions. Oral iron is not given at the same time because absorption is reduced. Concurrent angiotensin-converting-enzyme inhibitors may increase the risk of hypersensitivity reactions.

Pregnancy and breastfeeding. Avoid in the first trimester; use in the second and third trimesters when oral iron fails or in severe anaemia. Compatible with breastfeeding.

Common errors. Overdosing from skipping the deficit calculation; checking ferritin too soon (falsely raised for weeks after a dose); giving fast injection leading to hypotension.

Preparation. Slow injection: undiluted at 1 mL (20 mg) each minute, maximum 10 mL (200 mg). Infusion: dilute in 0.9% sodium chloride only; 100 mg in up to 100 mL over at least 15 minutes, 200 mg in up to 200 mL over 30 minutes, 500 mg in up to 250 mL over 3.5 hours.

Baseline. Haemoglobin, ferritin, transferrin saturation, phosphate and C-reactive protein.

Monitoring. Observe for 30 minutes after each dose with resuscitation equipment and adrenaline available. Check haemoglobin at 4 weeks and ferritin and transferrin saturation at least 4 weeks after the last dose. Withhold further iron if ferritin exceeds 500 µg/L or transferrin saturation exceeds 45%.

Referral and escalation. For anaphylaxis, stop the infusion and give adrenaline 0.5 mg intramuscularly (adults), repeated after 5 minutes if needed, with fluids and airway support.