What is Ferric Derisomaltose?
Ferric Derisomaltose (FDI) is a dark brown liquid containing iron. It is a type of iron preparation which can be given through a drip into a vein (known as an infusion). FDI is sometimes recommended instead of iron tablets when iron tablets are not effective, can’t be used or where there is a need to deliver a larger concentration of iron quickly.
Iron plays a key role in many processes, especially in facilitating the formation of red blood cells and enabling them to carry oxygen around the body. A lack of iron can make us feel tired, dizzy, irritable, unable to sleep and lead to dry skin or hair loss.
Iron facts
- The human bodycontains3–4 grams of iron, approximately two-thirds of this iron is found in the red blood cells
- Iron is needed to produce haemoglobin, the protein that transports oxygen around the body in red blood cells, and myoglobin, a similar protein that is found inside muscle tissue
- Iron is found in many enzymes, such as those that aid energy production. It is also used by the body for assisting the immune system
- Each day, an adult male requires around 11 milligrams (mg) of iron and an adult woman requires around 25 mg. This daily requirement usually comes from dietary sources
Why am I being offered FDI?
FDI is used for treating iron deficiency. Iron deficiency anaemia can occur when your body is not getting enough iron and cannot produce enough red blood cells. It is common for women who are pregnant or who have just given birth to have iron deficiency anaemia. Some patients can be treated with oral iron tablets. However if these have not been improving your iron levels or cannot be taken your doctor will have suggested FDI because they feel it is the best method of treatment to help correct the iron levels in your body.
You may need FDI if:
- Blood tests have shown you have low iron stores which may lead to anaemia and oral iron tablets have not improved your iron levels or have made you feel unwell.
- You had a significant blood loss after the birth of your baby (causing your number of red blood cells and therefore, iron levels to be low), but otherwise you are feeling well
- You have chosen not to have a blood transfusion
FDI may be offered to you as an alternative to a blood transfusion. Although blood transfusions are safe, there are some risks associated with them, including a small risk of infection. FDI is not a blood product, so it does not have the associated risks of a blood transfusion. FDI is not recommended for use in the first trimester of pregnancy (up to 12 weeks). If you have a medical history of hepatic disease please discuss this with your doctor as FDI should be used with caution or avoided.
Side effects of the iron treatment
Like all medicines, FDI can cause side effects, although not everybody gets them. Your doctor or midwife will discuss all possible side effects with you before starting treatment. The iron infusion doesn’t hurt but you may feel a cold sensation in your arm while it goes in. It is common to experience dizziness, flushing, headache, high blood pressure, low blood pressure, low phosphate, feeling sick (nausea), and altered taste.
Specific side effects
Fishbane reactions usually occur within 5 minutes of starting an iron infusion and can cause light-headedness, dizziness, nausea, flushing, chest tightness, chest and back pain and joint pain. The effects of a Fishbane reaction are self-limiting (meaning they usually resolve without any further treatment). If you experience any of these symptoms during your iron infusion please alert the midwife or healthcare professional caring for you. To treat a Fishbane reaction the midwife or health professional will stop the infusion, reassure you and provide you with a glass of water. Pausing the infusion usually allows symptoms to reduce; the iron infusion can then be restarted slowly and usually completed. Having any reaction can be scary and your consent will be obtained before re-starting the iron infusion. Fishbane reactions occur in approximately 1 out of 100 patients.
Skin staining or tattooing is an uncommon risk that iron could leak and cause a stain to your skin which may be permanent. If you experience pain, discomfort, or notice leaking around the treatment site, please let your doctor or nurse know immediately. The rate of skin staining with intravenous iron infusions has been reported in clinical trials as 0.68-1.3%. This can occur at the site of administration or other body areas.
For all intravenous iron treatments administered directly into your arm, there is a low risk that you may experience an acute severe hypersensitivity reaction. Symptoms can include breathing difficulty, dizziness and swelling in the mouth. Your doctor or nurse will be monitoring you closely to make sure your body is tolerating the treatment. Tell your doctor or nurse if you experience any new symptoms during treatment. The procedure will be stopped immediately – they’ll take care of you, and let you know if it’s safe to restart the medication. You can find more information on possible side effects in the Medication Patient Information Leaflet.
Symptoms after the infusion has ended
A few days after treatment, you might experience headache, mild fever or joint pain – these symptoms usually settle on their own. You can contact your GP or ring MAC for advice if any concerning symptoms persist.
Reporting of side effects
If you experience side effects talk to your doctor, pharmacist or midwife. This includes any possible side effects not listed in the leaflet. You can also report side effects directly via the Yellow Card Scheme at Yellow Card | Making medicines and medical devices safer. By reporting side effects, you can help provide more information on the safety of this medicine.
Before receiving treatment
Treatment with FDI does not require any preparation. You will be consented for the administration of FDI and this will involve the doctor discussing your medical history to consider if FDI is the best iron treatment for you. You will be given the Medication Patient Information Leaflet to read and consider alongside this leaflet.
Have your usual meals on the day and make sure you are well-hydrated. Continue taking all your usual medications but stop taking iron tablets at least a day before your appointment. You will be given a date and time to attend for your iron infusion. Wear loose, comfortable clothes and a short-sleeved shirt. You can also bring along a book, or something to watch as the appointment can take about an hour. At the appointment you will be shown to a bed, have observations and a brief history taken. You will be asked to confirm if you have any allergies and a wristband will be applied. Your consent will be checked with you. We will then perform a monitoring of your baby to check that you and your baby are well whilst the medication is being delivered.
To receive FDI you will need a cannula (a small tube) into a vein, usually in your hand or arm, through which the medication will be delivered. A cannula is inserted with a small needle that may hurt initially but will not hurt when the needle is removed.
The midwife will then confirm your name, date of birth, allergies and the medication with you before commencing the infusion. It will take around 30 minutes to receive your iron infusion. Your midwife or healthcare professional will suggest you stay you for an additional 30 minutes afterwards to ensure you’re well before going home. Once the medication has been administered the cannula will be removed and a dressing applied. This will heal within a couple of days.
What happens after treatment?
A repeat blood sample will usually be taken around 4 weeks after the treatment to determine if your body’s iron stores are improved. It is recommended to have this blood test taken to continue to monitor iron levels in preparation for childbirth. If you need to recommence iron tablets you will be informed of this. Most patients only need one treatment to restore iron levels unless you have ongoing issues that affect your iron levels; this would be discussed with haematology.
What if I don’t want an iron infusion?
A healthcare professional will discuss with you the risks and benefits of any proposed treatment. You will have the opportunity to raise any questions or concerns before this procedure is commenced. If you choose not to have an iron infusion the doctor will discuss with you the alternative methods of treatment such as blood transfusion, continuing oral iron tablets or diet. Foods rich in iron include meat such as red meat, fish and eggs and plant-based foods such as beans, lentils, seeds and spinach. Studies have shown diet to be effective in the treatment of anaemia but will take longer to have effect. Always take iron tablets on an empty stomach with a glass of orange juice and avoid caffeine for one hour after the tablet to maximise absorption.
References
- Achebe, M. and DeLoughery, T. G. (2020). Clinical data for intravenous iron- debunking the hype around hypersensitivity. Transfusion. Volume 60, 1154-1159.
- British National Formulary (BNF, 2025). Ferric Derisomaltose. Online. Accessed at: Ferric derisomaltose | Drugs | BNF | NICE
- British Society for Haematology (2021). UK guidelines on the management of iron deficiency in pregnancy. Online. Accessed at: UK guidelines on the management of iron deficiency in pregnancy
- Caimmi, S. et al. (2022). Hypersensitivity to intravenous iron preparations. Children. Volume 9, 1-10.
- Canning M, Grannell L. (2020). A stain on iron therapy. Australian Prescriber. Volume 43, 160–163.
- Richards T. et al. (2021). Questions and answers on iron deficiency treatment selection and the use of intravenous iron in routine clinical practice. Annals of medicine. Volume 53, 274-285.
- Stein J. et al. (2010). Human Vitamin and Mineral Requirements. Nature Reviews Gastroenterology & Hepatology. Volume 7, 599–610.