Short Takes

13 Jun
2010

Short TakesINTRODUCTION

Iron-deficiency anemia (IDA) is a relatively commonplace medical problem that health care practitioners encounter in both ambulatory and inpatient settings. Causes can include increased iron demands, impaired gastrointestinal (GI) absorption, blood loss, and poor nutritional intake. Because of the mineral’s abundance in many foods, inadequate dietary intake is rarely the sole contributor to a clinical deficiency syndrome; however, it can accelerate the appearance of iron deficiency in the presence of other causes.

The recommended dietary allowances (RDAs) for iron can usually be met through dietary sources such as meats, spinach, eggs, and soybean products. Consequently, the therapeutic use of iron supplements is truly necessary only in a relatively small percentage of patients. It is estimated that IDA occurs in about 10% of adult women and in 1% of adult men.

This article offers guidelines to help practitioners carefully select patients for oral iron supplementation and to help them maximize their patients’ therapeutic response and tolerance to oral iron therapy.

TOO MUCH IRON?

The literature supports the contention that iron therapy is often overprescribed. For instance, in a retrospective study of prescribing patterns of internal medicine house officers, 64% of patients who had been prescribed iron therapy had not completed the appropriate diagnostic testing. Upon further review of the medical records, it was determined that 43% of the patients did not meet the criteria for iron deficiency. On the basis of our anecdotal experience, as well as on our findings in the literature, the superfluous use of iron is also quite prevalent in extended-care facilities.

Iron therapy is associated with several potential shortcomings and complications:

1.  Iron can exacerbate symptoms of gastroesophageal reflux disease (GERD). Therapeutic doses of oral iron preparations sometimes cause significant adverse GI effects in up to 20% of patients. Iron can have a corrosive effect on the GI mucosa, resulting in constipation, nausea, diarrhea, abdominal pain, and dark stools. canada pharmacy mall

2.  In worst-case scenarios, excessive iron ingestion can also lead to iatrogenic hemochromatosis, with subsequent multiple-organ damage and increased vulnerability to a wide array of infections.

3.  Iron chelates many drugs in the GI tract, thus interfering with their systemic absorption. Some agents that are sequestered by iron include the quinolones, the tetracyclines, and levothyroxine. Conversely, antacids and aluminum-containing drugs can decrease iron absorption.

Pharmaceutical manufacturers have attempted to reduce iron’s adverse GI effects by formulating extended-release preparations. Unfortunately, the reduction of adverse events with these products generally corresponds to a reduction in iron that is actually absorbed. Although iron absorption is reduced by about half when the mineral is given with food, compared with when it is taken on an empty stomach, some believe that the tradeoff of improved GI tolerance with food offsets the loss of iron’s bioavailability. Furthermore, the bioavail-ability of iron is thought to be driven by “body need.” The bioavailability can range from 5% to 10% in healthy patients to 20% in patients with severe iron deficiency.

Vitamin C (ascorbic acid) 500 mg to 1 g, taken with each dose of iron, improves absorption by only another 10% from the baseline value. Thus, adding ascorbic acid to iron is usually not practical; this endeavor can contribute to ascorbic acid-related side effects, including the precipitation of calcium oxalate kidney stones in predisposed patients. Vitamin C also contributes to the problems inherent in any polypharmaceu-tical situation. eriacta tablets

Given this proclivity for the overuse of iron and some of its impending risks, it is important to understand the therapeutic nuances of appropriate iron prescribing. Of course, this effort begins with getting the correct diagnosis.

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