OVERSATURATION OF TRANSFERRIN AFTER INTRAVENOUS FERRIC GLUCONATE (FERRLECIT(R)) IN HEMODIALYSIS-PATIENTS

Background. Chronic haemodialysis causes blood loss and iron-deficienc y. This can be corrected with intravenous preparations, e.g. sodium fe rric-gluconate (FeGl). In two patients complaints of hypotension and m alaise during FeGl infusion coincided with high levels of serum iron a nd a calculated transferrin iron saturation above 100%. Iron toxicity could be the cause of these complaints, Free iron is known to aggravat e the toxicity of free radicals and other reactive oxygen products tha t are constantly formed in the body. We compared four rates of FeGl in fusion with regard to iron parameters. Methods. 20 dialysis patients r eceived a total of 36 infusions of FeGl. A rapid infusion of 125 mg (P rotocol A (n=10)) or 62.5 mg (Protocol B (n=7)) of FeGl was given duri ng the last 30 min of dialysis. A slow infusion of 125 mg (Protocol C (n=9)) or 62.5 mg (Protocol D (n=10)) was given during 4 or 4.5 h of d ialysis. Blood was taken at regular intervals before, during, and afte r dialysis for determination of serum iron, transferrin, ferritin, hae matocrit, total protein, albumin, and lactate dehydrogenase (LDH). Tra nsferrin saturation was calculated from transferrin and serum iron. Re sults. With rapid infusion A (125 mg) the highest levels of serum iron (median 120 (range 40-159) micromol/l) and transferrin saturation (20 7 (84-331)%) were seen at the end of the infusion, These were signific antly higher than the peak levels with B, C, and D (P less than or equ al to 0.03). With rapid infusion B (62.5 mg), peak levels were interme diately high (serum Iron 61 (50-96) mu mol/l; transferrin saturation 1 18 (91-174)%). With slow infusion C(125 mg) similar peak levels were s een (serum iron 83 (43-106) mu mol/l; transferrin saturation 141 (88-1 72)%). With slow infusion D (62.5 mg), the lowest peak levels were see n (serum iron 38 (31-55) mu mol/l; transferrin saturation 78 (43-92)%) . These levels were significantly lower than those with A, B and C (P less than or equal to 0.002). Only with D all patients showed a transf errin saturation lower than 100%. Ferritin was increased before the ne xt dialysis in all patients. LDH was not significantly elevated during any infusion. Conclusions. The commonly used rapid infusion rate (A) of FeGl causes 'oversaturation' of transferrin. This is compatible wit h iron toxicity due to free iron which may explain our patients' compl aints. Free iron cannot be measured directly. LDH as a crude measure o f cell damage was not elevated. Better measurements to prove free iron toxicity, like lipid peroxides, are not yet readily available. Infusi on during a longer period at a lower dose (D) is effective and elimina tes 'oversaturation' of transferrin and probably the danger of iron to xicity.