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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pain control using intramuscular analgesia is often unsatisfactory in sickle cell patients. In a pilot study, 15 patients with sickle cell anemia (SS) and one patient with SB thalassemia in vaso-occlusive crisis were treated with the Patient-Controlled Analgesia (PCA) technique using a Pharmacia Deltec Programmable pump (CADD PCA). Age range was 19-50 years (median = 27); there were nine females and seven males. The protocol consisted of 3 days of therapy using a background of continuous infusion meperidine. The starting dose was 20 mg/hr and was escalated to 30 mg/hr. The average amount given was 25.8 mg/hr. One to two boluses of 2.5-5.0 mg/dose (mode = 5.0) were also allowed each hour. In addition, patients number 8 through 16 were given hydroxyzine (Vistaril) 50 mg PO q6h. The number of days in pain prior to study entry (mean +/- SD) was 3.3 +/- 1.6. The number of pain sites per patient was 3.6 +/- 1.2. Using categorical and analog pain scales, patients' pain scores decreased only about 30%. However, most patients were fairly satisfied with the treatment and rated it overall as follows: 1 poor, 1 fair, 3 good, 6 very good, 4 excellent, 1 no comment. Patients number 8 through 16 gave higher ratings probably because a more idealized dosage regimen was being used by that time in the study. There were no adverse effects or major problems noted. It is our impression that PCA, when optimized, will be a safe and effective alternative method for providing patients with sickle cell vaso-occlusive crisis pain relief.
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PMID:Patient-controlled analgesia in patients with sickle cell vaso-occlusive crisis. 229 91

Iron overload caused by lifelong transfusion-dependent anaemias, such as beta-thalassaemia major, usually results in lethal cardiac toxicity in the second decade of life if not treated by iron chelation. There is no physiological mechanism for excreting the excess iron accumulated from blood transfusions and, unlike hereditary haemochromatosis, venesection is not an option. Therefore, chelation therapy is the only way to remove excess iron. This must be removed while not depriving cells of the essential iron needed for normal metabolism. Additionally, the iron chelator must prevent iron from participating in the generation of harmful free radicals. Parenteral chelation therapy with deferoxamine (desferrioxamine) is well established as promoting negative iron balance, reversing cardiac toxicity, and prolonging life expectancy well into the fourth decade of life and, most likely, beyond. Unfortunately, poor compliance with the rigours of parenteral treatment in a minority of patients limits its regular use, resulting in reduced life expectancy in these patients. Use of deferoxamine in excessive dosages may result in growth retardation, sensorineural ototoxicity and ocular toxicity, as well as bone deformities. These effects can be largely avoided if the dosage is adjusted to take account of the degree of iron overload (using the therapeutic index) and if the mean daily dose does not exceed 40 mg/kg. Nevertheless, it is recommended that patients be regularly monitored for such adverse effects. Deferiprone (L1; CP20) is an orally absorbed bidentate hydroxypyridinone iron chelator that can induce urinary iron excretion, promote negative iron balance and reduce hepatic iron levels in some transfusion-dependent patients, particularly in those who are markedly iron overloaded and have not received regular deferoxamine therapy. The long term efficacy and toxicity of deferiprone are the subjects of some controversy, and the published results of randomised controlled trials are awaited. Preliminary results suggest that when currently recommended dosages of deferiprone (75 mg/kg/day) are used, hepatic iron settles at levels that still put most patients at an increased risk from iron overload. A number of adverse effects may occur, and require cessation of therapy in up to 30% of patients. These effects include arthritis, nausea and (most seriously) agranulocytosis in 0.6 to 4% of patients. The risk of the latter complication means that frequent white blood cell counts are mandatory for patients taking this drug. There remains an urgent need to identify an orally active chelator regimen that is as effective as deferoxamine and has an acceptable degree of tolerability.
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PMID:A risk-benefit assessment of iron-chelation therapy. 942 39

Iron chelation therapy with desferrioxamine (DFO) has dramatically improved the outlook in beta-thalassemia. Parenteral DFO reduces tissue iron stores, prevents iron-induced organ damage, and reduces morbidity and mortality, with little serious toxicity. However, the burden of prolonged subcutaneous portable pump infusions, high cost, and patient noncompliance have prompted the development of new methods of administration and new formulations of DFO as well as oral iron chelators. Deferiprone (L1), the only oral iron chelator studied in large long-term clinical trials, is less effective and more toxic than DFO and may not adequately control iron overload; however, compliance and quality of life are improved. Combinations of two iron chelators (such as parenteral DFO plus oral L1, or 2,3-DHB; or oral L1 plus HBED) have been shown to produce additive and synergistic effects, explained by the shuttle hypothesis. Iron bound to a "shuttle"--an oral agent that mobilizes tissue iron--is exchanged in the bloodstream with a "sink"--such as parenteral DFO--and excreted via the kidneys, while the shuttle is reutilized. Combination therapy may produce enhanced iron excretion, target specific iron compartments, minimize side effects, increase treatment options, improve compliance, and facilitate individualization of therapy. Better understanding of the kinetics of iron metabolism, iron overload, and chelation should improve therapeutic strategies.
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PMID:Chelation therapy in beta-thalassemia: an optimistic update. 1160 71

In the majority of cases, microcytosis is the result of impaired hemoglobin synthesis. Disorders of iron metabolism and protoporphyrin and heme synthesis, as well as impaired globin synthesis, lead to defective hemoglobin production and to the generation of microcytosis and microcytic anemia. Iron deficiency anemie, anemia of chronic diseases, thalassemias, congenital sideroblastic anemias and homozygous HbE disease are the main representatives of microcytosis and microcytic anemias. Serum iron, total iron binding capacity, transferrin saturation, serum ferritin, serum transferrin receptor, transferrin receptor-ferritin index, and zinc-protoporhyrin concentration in erythrocytes are tests used for assessment of iron deficiency. The convention laboratory test for diagnosing iron deficiency is the measurement of serum ferritin. The most precise method for evaluating body iron stores is the examination for iron on aspirated bone marrow or marrow biopsy. Increased content of Hb A2 over 3.5% is diagnostic for beta-thalassemia. Presence of ringed sideroblasts is characteristic of sideroblastic anemias. Hemoglobin electrophoresis is required for the diagnosis of hemoglobinopathy E. The optimal therapeutic regimen in iron deficiency anemia used in this country is to administer 100 mg of elemental iron twice daily separately from meals. Ferrous sulphate (Ferronat Retard tbl. or Sorbifer Dulures tbl.) which are slow-releasing iron formulations are preferred because of their low cost, high bioavailability and low side-effects. Parenteral iron therapy is justified only in patients who cannot absorb iron, who have blood losses that exceed the maximal absorptive capacity of their intestinal tract or who are totally intolerant of oral iron. However, parenteral iron therapy may be associated with serious and even fatal side-effects.
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PMID:[Microcytic and hypochromic anemias]. 1563 79