What is the recommended dose and administration schedule of Monoferric (ferric derisomaltose) for a 34-year-old female patient with severe iron deficiency anemia (Hemoglobin 74 g/L, Mean Corpuscular Volume (MCV) 57 fL, ferritin 2 mcg/L, iron 4 umol/L) who has failed oral iron and vitamin C supplementation?

Monoferric (Ferric Derisomaltose) Dosing for Severe Iron Deficiency Anemia

For this 34-year-old female patient with severe iron deficiency anemia (Hb 74 g/L, MCV 57 fL, ferritin 2 mcg/L) who has failed oral iron therapy, the recommended dose of Monoferric (ferric derisomaltose) is 1500 mg administered as a single intravenous infusion.

Patient Assessment and Indication

• The patient has clear evidence of severe iron deficiency anemia with hemoglobin of 74 g/L (well below 100 g/L), microcytosis (MCV 57 fL), extremely low ferritin (2 mcg/L), and low serum iron (4 umol/L) 1
• She has failed oral iron supplementation despite concurrent vitamin C administration, which is a clear indication for intravenous iron therapy 1
• With hemoglobin below 100 g/L (10 g/dL) and previous intolerance/failure of oral iron, intravenous iron is the first-line treatment 1

Dosing Calculation

• For patients with hemoglobin between 70-100 g/L and body weight <70 kg (patient weighs 68 kg), the recommended total iron dose is 1500 mg 1
• This dosing is based on the simplified dosing scheme that has replaced the more complex Ganzoni formula, which was prone to error and often underestimated iron requirements 1
• For patients with hemoglobin below 70 g/L (this patient is at 74 g/L, just above this threshold), an additional 500 mg might be considered, but the standard 1500 mg is appropriate for this patient 1

Administration Protocol

• Monoferric (ferric derisomaltose) can be administered as a single infusion of 1500 mg over approximately 15-30 minutes 1, 2
• Unlike iron dextran preparations, ferric derisomaltose does not require a test dose as the risk of anaphylactic reactions is significantly lower 1
• Resuscitation facilities should be available during administration as with all intravenous iron preparations 1

Monitoring and Follow-up

• Hemoglobin levels should begin to rise within 1-2 weeks, with an expected increase of at least 2 g/dL within 4 weeks of treatment 1
• Follow-up laboratory testing should be performed at 8-10 weeks post-infusion to assess treatment response 1, 3
• Monitor hemoglobin, red cell indices, and iron parameters (ferritin, transferrin saturation) 1
• Once normal, hemoglobin and red cell indices should be monitored at 3-month intervals for the first year, then after a further year, and again if symptoms of anemia develop 1

Advantages of Single-Dose Intravenous Iron

• Intravenous iron shows faster response and better tolerability compared to oral iron in patients with severe iron deficiency anemia 1
• A single high-dose infusion improves compliance compared to multiple smaller doses 1, 4
• Studies suggest that a total cumulative dose of 1500 mg is closer to the actual iron deficit in most patients with iron deficiency anemia, compared to lower doses of 1000 mg 4
• The percentage of patients requiring retreatment is significantly lower with a 1500 mg dose compared to 1000 mg 4

Potential Side Effects and Precautions

• Common side effects include headache, dizziness, nausea, abdominal pain, constipation, rash, and injection-site reactions 2
• Gastrointestinal side effects are less common with intravenous iron compared to oral iron 2
• Monitor for signs of hypersensitivity during and after administration 1
• Avoid administration in patients with iron overload (not applicable in this case with ferritin of 2 mcg/L) 1

This dosing recommendation is based on current guidelines for iron deficiency anemia management and is appropriate for this patient's specific clinical parameters, particularly considering her failed response to oral iron therapy and the severity of her anemia.