Heme arginate (or haem arginate, brand name NORMOSANG) has been used to treat acute porphyrias. NORMOSANG successful uses in Europe and South Africa, but it has not been approved for use in the United States. Heme arginate consists of haem complexed with the amino acid arginine. This forms a stable compound. Haem arginate works by replenishing haem stores within the body. By negative feedback, haem arginate inhibits the initial rate-limiting enzyme of the haem synthetic pathway, ALA synthase (Delta-aminolevulinic acid dehydratase). The most frequent complication is phlebitis at the site of infusion. This can be reduced by giving the infusion of haem arginate in a protein buffer such as stabilized human serum or human serum albumin. In addition, there were studies, which revealed, that heme arginate induced beneficial effects in some myelodysplastic syndrome (MDS) patients and had very few side effects. In addition was shown, that heme arginate could be useful in the treatment of thalassemia intermedia.