Reactions to intravenous iron are rare

An iron infusion is as safe as any other infusion

True anaphylaxis used to happen with the older iron dextrans from the 1960’s/1970’s. These products are no longer used. However, there is a huge hangover and fear confusing everyone (doctors and patients). With new preparations reactions are rare, but as with any treatment there are:

Patients with iron deficiency are anxious. This is part of the iron deficiency. Take time to ensure they are relaxed, well hydrated and in a calm environment. Similarly the staff need to be professional and clam.

Common 5-10 per 100 develop a flushing reaction (see below). This is not an allergy. As the iron enters the body a very small amount is free iron – this causes flushing, nausea, giddiness or headache. It can be very disconcerting if people are not prepared and cause panic to the patient and staff. This is NOT and allergy. It is iron inducing endothelial nitric oxide synthetase (eNOS) leading to NO release – rarely a lower BP.
It responds to stopping the infusion then restart the infusion 5 minutes later. It is commonly misconstrued as an allergy – it is not and benadryl dosen’t help (old habits wont die!). It is exactly the same as getting IV contract for a CT or MRI scan.

This happens about 1 in 100: you get symptoms similar to flushing and can develop and urticaria, rash and a cough. This similar responds to stopping the infusion, reassurance and a single steroid injection. In someone with a history of bad allergies (needing hospital treatment) then premed with a steroids can be used. Treatment is to stop the infusion and give IV steroid (hydrocortisone) then after 5-10 mins restart slowly and complete the treatment.

True allergy happens to 1 in 10,000: an anaphylactic – like reaction (CAPRA) again this responds to steroids and if needed adrenaline. All units have a policy for this. The reaction rate is the same as for an antibiotic.

Post infusion flu
Common, this is aches and pains, temperature and flu like symptoms that develop the next day and last 48hours. This responds to ‘knowing that it can happen’ and ibruprofen if needed. Its so common we regard this as normal.



Author: Professor Toby Richards

Mr Toby Richards is a Professor of Surgery at University College London. He has pioneered anaemia management and intravenous iron therapy in the UK. His underlying belief is that optimising patient’s health and fitness before surgery will improve their recovery and benefit their outcomes. He has embedded clinical research and development into all areas of practice.

Book an appointment..

You can download our patient information sheet: Patient Information Sheet

To book an appointment please email us a short history and copy of your blood results, we will respond with options about online or in person consultations and availability for an infusion (normally most Monday and Friday afternoons):

Our staff are available and happy to answer your every question

020 3875 8171