Macdougall I C
Department of Renal Medicine, King's College Hospital, London, England, United Kingdom.
Kidney Int Suppl. 1999 Mar;69:S61-6. doi: 10.1046/j.1523-1755.1999.055suppl.69061.x.
Iron supplementation has become an integral part of the management of patients receiving epoetin therapy, and clinicians have found it necessary to learn how and when to use it to the best advantage. Three routes of administration for iron are available: oral, intramuscular, and intravenous. Oral iron has the advantage of being simple and cheap, but it is limited by side-effects, poor compliance, poor absorption, and low efficacy. Intravenous iron is the best means of guaranteeing delivery of readily available iron to the bone marrow, but it requires greater clinical supervision. The i.v. iron preparations vary widely in their degradation kinetics, bioavailability, side-effect profiles, and maximum dose for single administration. Iron dextran is hampered by a small but significant risk of anaphylaxis, whereas all i.v. iron preparations can induce "free iron" reactions if the circulating plasma transferrin is overloaded. Intravenous iron may be given in advance of epoetin therapy, as concomitant treatment to prevent the development of iron deficiency, as treatment of absolute or functional iron deficiency, or as adjuvant therapy to enhance the response to epoetin in iron-replete patients. Markers of iron status that may indicate a need for i.v. iron include a serum ferritin of less than 100 microg/liter, a transferrin saturation of less than 20%, and a percentage of hypochromic red cells more than 10%. Various regimens are available for giving i.v. iron: low-dose administration of 20 to 60 mg every dialysis session in hemodialysis patients, medium-dose administration of 100 to 400 mg, and high-dose administration of 500 to 1000 mg. Iron sodium gluconate can only be given as a low-dose regimen because of toxicity, whereas the only preparation suitable for high-dose administration is iron dextran. Although concerns have been raised regarding iron overload and long-term toxicity with i.v. iron therapy in terms of increased risk of infections, cardiovascular disease, and malignancy, there is little evidence to substantiate this in patients receiving epoetin. Care should be taken, however, to prevent the serum ferritin rising above 800 to 1000 microg/liter and the transferrin saturation above 50%. Provided this is done, the benefits of i.v. iron almost certainly outweigh the risks in terms of optimizing the response to epoetin therapy.
铁剂补充已成为接受促红细胞生成素治疗患者管理的一个重要组成部分，临床医生发现有必要了解如何以及何时使用铁剂才能达到最佳效果。铁剂有三种给药途径：口服、肌肉注射和静脉注射。口服铁剂具有简单且便宜的优点，但受副作用、依从性差、吸收不良和疗效低的限制。静脉注射铁剂是保证将易于利用的铁输送到骨髓的最佳方法，但需要更严格的临床监测。静脉注射铁剂制剂在降解动力学、生物利用度、副作用特征和单次给药最大剂量方面差异很大。右旋糖酐铁存在虽小但显著的过敏风险，而所有静脉注射铁剂制剂如果循环血浆转铁蛋白过载都可引发“游离铁”反应。静脉注射铁剂可在促红细胞生成素治疗前给予，作为预防缺铁发生的联合治疗，作为绝对或功能性缺铁的治疗，或作为在铁储备充足患者中增强对促红细胞生成素反应的辅助治疗。可能提示需要静脉注射铁剂的铁状态指标包括血清铁蛋白低于100微克/升、转铁蛋白饱和度低于20%以及低色素红细胞百分比超过10%。有多种静脉注射铁剂的给药方案：血液透析患者每次透析 session 给予20至60毫克的低剂量给药、100至400毫克的中剂量给药以及500至1000毫克的高剂量给药。由于毒性，葡萄糖酸铁钠只能采用低剂量方案给药，而唯一适合高剂量给药的制剂是右旋糖酐铁。尽管有人对静脉注射铁剂治疗中因感染、心血管疾病和恶性肿瘤风险增加而导致的铁过载和长期毒性表示担忧，但在接受促红细胞生成素治疗的患者中几乎没有证据能证实这一点。然而，应注意防止血清铁蛋白升至800至1000微克/升以上以及转铁蛋白饱和度超过50%。只要做到这一点，静脉注射铁剂在优化对促红细胞生成素治疗反应方面的益处几乎肯定超过风险。
