Intravenous iron treatment has a shorter infusion time and fewer adverse adverse events when ferric carboxymaltose is used compared to iron polymaltose, a study in women at a Victorian maternity service has shown.

Clinicians at the Royal Women’s Hospital in Melbourne made the observation after they switched from iron polymaltose (Ferrum H injection) to ferric carboxymaltose (Ferinject) as the treatment for iron deficiency anaemia in obstetric and gynaecology patients in 2014.

In a retrospective review of 221 patients they found the rate of adverse events was 16.2 % in 111 women who received iron polymaltose and 1.8% in the 110 women who received ferric carboxymaltose. The most common adverse reactions were rash and urticaria in the iron polymaltose group, and dizziness or light-headedness in the ferric carboxymaltose  group. There were no cases of anaphylaxis in either group.

The researchers said the lower rate of adverse reactions with ferric carboxymaltose  might be explained by it not containing any dextran, which makes it less immunogenic. Ferric carboxymaltose  also had a more stable carbohydrate shell, which has been postulated to allow more gradual release of unbound and labile iron that may cause cell toxicity.

Both groups of women achieved  increased haemoglobin levels within one to 12 weeks, though the increases in haemoglobin levels were slightly higher among pregnant women receiving iron polymaltose compared to those receiving ferric carboxymaltose  (26.4 vs 17.9 g/L).

The hospital switched to ferric carboxymaltose from iron polymaltose because its shorter infusion time (15 minutes vs five hours) allowed a shorter length of patient admission and reduced staffing requirements to administer the infusion.

Ferric carboxymaltose  had  a higher price ($307.50) than iron polymaltose ($23.70) but the cost difference would be offset by reduced need for nursing care to administer infusions and reduced costs of managing adverse reactions, the researchers suggested.

However, they also noted that the entire dose of iron could be given at one sitting with iron polymaltose whereas with ferric carboxymaltose  doses greater than 1000 mg required infusion over two occasions, one week apart. In practice, eight of the 57 patients (14%) who required a second infusion did not return, resulting in lower number achieving their target total dose.

Nevertheless, they concluded that the adverse event rates revealed in their comparative study had provided clinical vindication for the switch from iron polymaltose to ferric carboxymaltose.

Published in International Journal of Obstetrics and Gynecology, the study authors declared no conflict of interest .