India · Ganzoni Equation · IV Iron Dose · Pregnancy · CKD · InFed · Iron Sucrose · Ferric Carboxymaltose
Total iron (mg) = Weight (kg) × (Target Hb − Actual Hb) × 2.4 + Iron stores (mg)
⚠️ Anaphylaxis risk with IV iron — resuscitation facilities must be available
⚠️ Iron dextran requires 25mg test dose before TDI
⚠️ Avoid IV iron in active infection
⚠️ FCM can cause hypophosphataemia — monitor phosphate
| Product | Dose per infusion | Max single dose | Notes |
|---|---|---|---|
| Iron sucrose (Venofer) | 100–200 mg in 100mL NS over 15–30 min | 200 mg | Preferred in CKD/dialysis; safest profile |
| Ferric carboxymaltose (FCM) | 500–1000 mg in 250mL NS over 15 min | 1000 mg (20 mg/kg) | Can correct large deficits in 1–2 doses; preferred in pregnancy |
| Iron dextran (Imferon) | TDI — full deficit in one infusion | Total deficit (slow infusion) | Test dose 25mg required; anaphylaxis risk higher |
The Ganzoni equation calculates the total elemental iron required to restore haemoglobin to target levels and replenish iron stores. The formula: Total iron (mg) = Body weight (kg) × (Target Hb − Actual Hb g/dL) × 2.4 + Iron stores (mg). The factor 2.4 accounts for the iron content of haemoglobin (0.34% iron by weight) and blood volume (approximately 70 mL/kg). Iron stores are typically 500 mg for adults weighing more than 35 kg, and 15 mg/kg for those weighing 35 kg or less. In severely iron-deficient patients, stores may already be zero — reduce accordingly.
Iron deficiency anaemia affects over 50% of pregnant women in India (NFHS-5 data) — one of the highest rates globally. IV iron is increasingly preferred in the second and third trimester when oral iron has failed, is not tolerated, or when rapid correction is needed pre-delivery. Ferric carboxymaltose (FCM) — brands: Encicarb, Monofer — is now recommended in Indian obstetric practice for its single-dose high-dose convenience. The target Hb in pregnancy is 11 g/dL (WHO); the second trimester target is 10.5 g/dL due to physiological haemodilution. Iron stores are typically set to zero in severely deficient pregnant women.
Oral iron absorption is markedly reduced in CKD due to elevated hepcidin levels. IV iron sucrose is the standard of care in dialysis-dependent CKD patients — typically 100 mg per dialysis session for 10 sessions to replenish deficit, then maintenance doses of 100 mg every 1–2 weeks as guided by ferritin and TSAT. Target serum ferritin: 200–500 ng/mL; TSAT: 20–50% (KDIGO 2012). Avoid IV iron when ferritin >500 ng/mL or TSAT >50%.