Ferric Derisomaltose

Ferric derisomaltose is an intravenous iron-carbohydrate complex that allows a full replacement dose, up to 20 mg/kg, in one infusion. It is supplied as 100 mg/mL elemental iron.

Classification. Parenteral iron; iron-carbohydrate complex.

Mechanism. Strongly bound iron is released slowly to the reticuloendothelial system, and iron is passed to transferrin for erythropoiesis and storage.

Pharmacokinetics. Terminal half-life is about 20 hours, longer than with other intravenous irons. Renal clearance is negligible.

Iron deficiency anaemia (adults when oral iron is not suitable).

• Dose: up to 20 mg/kg as a single dose, with a cumulative dose of 1000 mg for adults weighing 50 kg or more and haemoglobin of 10 g/dL or more; 1500 mg for lower haemoglobin; the deficit calculation (weight in kg multiplied by target minus actual haemoglobin in g/dL, multiplied by 2.4, plus 500 mg) is an alternative.
• Maximum: 20 mg/kg (about 1500 mg) in a single dose; doses above 1000 mg are infused over at least 30 minutes. Loading dose: none. Repeat doses are not given within 4 weeks.

Adjustments. Kidney: none; used in chronic kidney disease. Liver: avoid in decompensation. Hypophosphataemia occurs less often than with ferric carboxymaltose.

Children. Not advised under 14 years in many regions; paediatric use is specialist directed.

Contraindications. Hypersensitivity, non-iron-deficiency anaemia, iron overload, serious active infection.

Adverse effects. Infusion reactions (flushing, back pain, hypotension), rash, nausea, injection-site discolouration. Serious hypersensitivity reactions are rare. Hypophosphataemia can occur.

Interactions. Not given with oral iron.

Pregnancy and breastfeeding. Avoid in the first trimester; used in the second and third when benefit outweighs risk. Compatible with breastfeeding.

Common errors. Overdosing by not capping the dose; repeating within 4 weeks; mistaking transient ferritin rise for repletion.

Preparation. Dilute in 0.9% sodium chloride only; doses up to 1000 mg in 100 mL over at least 20 minutes; smaller doses (up to 500 mg) may be given undiluted as a bolus no faster than 250 mg/min.

Baseline. Haemoglobin, ferritin, transferrin saturation, phosphate.

Monitoring. Observe for 30 minutes after the dose. Haemoglobin at 4 weeks, ferritin and transferrin saturation at least 4 weeks after the last dose; check phosphate in those with prior hypophosphataemia, malabsorption or repeat dosing.

Referral and escalation. Anaphylaxis: stop the infusion, give adrenaline 0.5 mg intramuscularly (adults), and resuscitate.