Can iron sucrose (Venofer) be given to a patient with a history of asthma and allergy in a primary

Fråga: Can iron sucrose (Venofer) be given to a patient with a history of asthma and allergy in a primary care setting?

The question concerns a 42-year-old woman who has been operated on with a gastric bypass a few years ago. She has had anemia for a few years and has been treated with per oral iron polysaccharide (Niferex) without effect. She has recently been given iron sucrose (Venofer) intravenously in a hematology department with good results and has been referred back to her general practitioner for continued treatment with intravenous iron sucrose. The patient has asthma, eczema and a prick test verified allergy to cat, dog and mite. The questioner wants to know if it is suitable that this patient is given intravenous iron sucrose in the primary care setting considering the risk of potentially fatal anaphylactoid reactions mentioned in the SPC and also if there is an increased risk of a reaction when treating for the second time.

Sammanfattning: Literature indicates a very low frequency of anaphylactoid reactions to iron sucrose and it can be given in a primary care setting. Preparations should be the same as in all parenteral administration of drugs.

Svar: Venofer contains iron sucrose. The safety profiles for different parenteral iron preparations vary. Compared to iron dextran, iron sucrose has displayed a much lower frequency of anaphylactoid reactions. Using data collected and analysed from semi annual safety reports submitted to worldwide regulatory authorities a frequency of 52 anaphylactoid reactions consequent to the administration of 20 million doses of iron sucrose injection given to 1004477 patients worldwide. Twenty-two of these cases were considered serious which is equal to an incidence of 0.002%. These numbers are based on spontaneous reports though, and therefore could underestimate the true incidence (1). This low level of incidence however was confirmed by another study with data from 61 centres in the United States in which no anaphylactoid reactions was seen on administration of 8590 doses to 665 patients on hemodialysis (1). In a study where the US Food and Drug Administration´s (FDA) Freedom of Information (FOI) surveillance database was used to study intravenous iron preparations between 1997 and 2002 a higher risk of adverse events was found for iron dextran than any other intravenous iron preparation. Indications were also found that iron sucrose has the lowest risk of hypersensitivity reactions (2). The absolute frequency of life threatening adverse drug events (ADE) was 0.6 per million administered doses of iron sucrose in another study based on material from FDA (3).

In an open label prospective study of 23 patients with a history of hypersensitivity on administration of iron dextran the safety profile for iron sucrose was studied. No serious side effects were recorded. Minor reactions resolved spontaneously (4). Hypersensitivity or absence of hypersensitivity to iron dextran does not necessarily imply that the patient has the same reaction to other intravenous iron preparations (1).

In the Swedish Medical Products Agency´s adverse reaction database Swedis there are three reported cases of anaphylactoid reactions to iron sucrose. In one of the cases the patient had a history of treatment with intravenous iron without reaction, it is not specified however, whether the previous treatment was with iron sucrose or another preparation. In one case the patient had had a mild reaction to iron sucrose at an earlier occasion (5).

The manufacturer of Venofer recommends caution on administration of parenteral iron preparations (6). Venofer was introduced in 1986 in Sweden and since then there has been no apparent pattern of occurrence of hypersensitivity reactions in patients with allergy in particular according to a company representative. Iron dextran has the downside that endogenously formed antibodies can give a reaction upon administration. This is not a problem with iron sucrose. Iron sucrose is currently given in primary care settings with good results, many examples of this exist in the sparsely populated areas of Sweden. It is important that the preparation is not administered to quickly since that can lead to saturation of the transferrin and a hypotensive reaction to iron (7).