Iron deficiency is a common problem in general practice. Traditionally it has been treated with oral tablets, intramuscular injections or intravenous administration. Each of these modalities have their own problems.
While tablets are first line therapy, they take several months to work and are associated with significant gastro-intestinal side effects. Intramuscular injections are painful and may lead to staining of the skin. Previous intravenous formats of iron have been associated with serious side effects during administration, most notably anaphylaxis.
Rapid replenishment of blood and iron stores is needed for pre-operative patients where blood loss during or prior to surgery can be expected. Bowel surgery, gynaecological operations and major joint replacements are those where haemoglobin and iron replacement needs pre-operative optimisation.
Of the three groups joint replacements account for the majority of patients in the Northern Rivers presenting to surgery at risk of iron deficiency. However, bowel surgery patients were the most likely to have anaemia and they also pose the highest surgical risk.
The earlier iron treatment is started the better and iron infusions can be done in iron deficient patients with a positive faecal occult blood test (FOBT) even prior to diagnosis.
Iron deficiency is usually diagnosed on a blood ferritin level. However, ferritin is also an acute phase reactant and may be elevated in iron deficient patients with cancer or other inflammatory conditions. Such patients will have a raised CRP, normal ferritin and low iron saturation, so it is important to check CRP in conjunction with iron studies.
Ferric carboxymaltose (Ferinject) is a relatively new form of intravenous iron replacement that is associated with fewer side effects. As such, it is feasible to give in outpatient settings and larger general practice surgeries. Experience to date suggests high levels of patient satisfaction with this approach.
All facilities undertaking this new therapy need to have protocols in place to manage both the medical and legal risks of administering intravenous iron solutions. Checklists for the indications, preparation and administration help address these risks. Informed consent should be obtained and short pamphlets such as those from BloodSafe and the NPS cover the relevant issues for patients.
Nursing and medical personnel should be familiar with the issues involved in intravenous iron administration. The National Prescribing Service Ferric Carboxymaltose Review from August 2014 covers the essential points. Blood eLearning Australia runs online courses that includes a module on Iron Deficient Anaemia (IDA). The course is accredited for CPD points for the RACGP, ACCRM and the Nursing and Midwifery Board of Australia. They also have developed an IDA app for android and iPhone that quickly runs through the protocol for investigating iron deficiency in children, men and women.
Despite lobbying the Pharmaceutical Benefits Scheme (PBS) there is no general practice item number for intravenous iron infusion. Costs include consumables, that run between $10 and $20 per infusion, and staff time.
Ferinject comes in 500 mg ampoules. The maximum dose that can be administered in any one session is 1000 mg and should not be repeated in under a week. Most patients will require between 1000 and 2000 mg. Dosage can be calculated on ideal body weight and the level of haemoglobin using either the Ganzoni or "Simplified" methods both of which are described in the MIMS.
Administration of 1000 mg of Ferinject can be accomplished in 15 minutes via intravenous drip or bolus push injection. A cannula should be used to minimise the risk of extravasation that can cause tattooing of the skin. A "butterfly" should not be used because of the greatly increased risk of this problem. Patients are closely monitored for adverse reactions during and for thirty minutes after the infusion.
Haemoglobin levels climb slowly after an iron infusion, so it is recommended that a check haemoglobin level be delayed for six weeks after the procedure.
Iron infusions are now easy to undertake in general practice as Drs Daniel Byrne and Pradeep Jayasuriya attest. In the Northern Rivers the NNSW LHD is keen to liaise with general practices to improve the timeliness of iron infusions for those patients at risk of perioperative complications.
The North Coast Primary Health Network's Iron Deficiency Anaemia Health Pathway guides practitioners through the process with information specific to our area.
The references mentioned above can be found in the hyperlinks of this article at gpspeak.org.au.