NHS Greater Glasgow & Clyde Area Drug and Therapeutics Committee
Greater Glasgow and Clyde Medicines
Medicines Update

Treatment of IDA - IV iron therapy

A new GGC guideline on the Treatment of Iron Deficiency Anaemia (IDA) is now available on StaffNet here. It provides information on two IV iron products, Ferinject® (ferric carboxymaltose) and Monofer® (iron isomaltoside 1000). The guideline does not cover the use of IV iron in the following clinical situations: pregnancy, postpartum anaemia, surgery/trauma, paediatrics (<16 years), patients with chronic kidney disease (CKD) stages 4-5.

Key messages, IV iron:

  • Should be reserved as a last resort in the treatment of IDA.
  • Does not produce a faster Hb response than oral iron (provided that the oral iron preparation is taken reliably and is absorbed adequately).
  • Can cause hypersensitivity reactions which may be life-threatening or fatal (only administer during working hours when adequate supervision is available).
  • Paravenous leakage may lead to permanent staining at the site of infusion.
  • Oral iron preparations should be discontinued at least 48 hours prior to an IV iron infusion. The ongoing need for oral iron should be reviewed following IV iron replacement.

 

Who should receive treatment with IV iron?

IV iron is rarely indicated, may produce severe adverse effects and should be reserved for patients who meet the inclusion criteria defined in section 4.2.1 of the full guideline.

 

My patient is on oral iron therapy – should it be continued?

It is recommended oral iron preparations are discontinued at least 48 hours prior to IV iron replacement. The need for oral iron should be reviewed following IV iron replacement. If an ongoing prophylactic dose is deemed necessary, oral iron should not be started for at least 5 days after the last IV iron infusion.

 

If indicated, which IV iron preparation should I use?

Ferinject® and Monofer® have different licensing and dosing restrictions. The treatment decision tool in section 4.2.3 of the full guideline can be used to guide product selection based on age, weight and Hb.

 

How do I calculate the dose and prescribe IV iron?

Appendix 1 (Ferinject®) and Appendix 2 (Monofer®) in the full guideline provide summary tables to assist with dosage calculation and prescribing. The dose of IV iron must be individually calculated for each patient based on their iron requirements. The maximum weekly dose, which can be administered by IV infusion, is 20mg iron/kg body weight (this is capped at 1,000mg per week for Ferinject®). If the cumulative iron dose exceeds this, there must be an interval of at least one week between administrations.

 

How do I ensure all prescribing and administration steps are completed?

A checklist is provided in Appendix 3 of the full guideline. This should be used pre-infusion, during infusion and post-infusion by prescribers and nursing staff. 

 

What monitoring is required?

Patients should be monitored for hypersensitivity reactions and extravasation. Administration should only occur during working hours when adequate supervision is available.

Hypersensitivity reactions

  • These include anaphylactic/anaphylactoid reactions, which may be potentially fatal.  
  • Caution is needed with every dose of IV iron that is given, even if previous administrations have been well tolerated.
  • IV iron should only be administered where there is immediate access to cardio-pulmonary resuscitation facilities and staff trained to evaluate and manage anaphylactic reactions. 
  • If hypersensitivity reactions or signs of intolerance occur, the treatment must be stopped immediately and appropriate management initiated.  
  • For further information refer to section 4.2.6.2 in the full guideline. 

My patient has had a serious hypersensitivity to an IV iron product in the past - can I use an alternative IV iron product?

No. An IV iron product should not be used in patients with known serious hypersensitivity to other parenteral iron products. In addition they should not be used in patients with known hypersensitivity to: the active substance, the product itself, or any excipients in the product.

Extravasation

  • Paravenous leakage of IV iron at the infusion site may lead to irritation of the skin and potentially permanent brown discolouration of the skin at the site of infusion.  
  • The most effective safeguard is to visually inspect the infusion site regularly.
  • In case of suspected paravenous leakage, treatment requires prompt attention. The infusion must be stopped immediately.
  • For further information refer to section 4.2.6.1 in the full guideline. 

 

What follow up is required after the infusion?

  • Treatment with IV iron should be clearly communicated with the patient’s GP and other healthcare professionals (via a discharge letter or outpatient clinic letter). This should include details on whether oral iron preparations have been discontinued (if relevant).
  • If required, patients should have arrangements in place for subsequent infusion(s) (in a hospital setting).
  • Patients should be made aware of follow up plans and advised of plans for stopping or continuing oral iron therapy.
  • A follow up blood test should be arranged 1 month after treatment with IV iron to assess Hb response (Hb levels should rise by at least 20g/L over 4 weeks).

 

Published 14/05/19. Medicines Update blogs are correct at the time of publication.