US Pharm. 2016;41(1):16.

Dosage is a critical issue for sickle cell anemia patients using the drug hydroxyurea. Patients taking the medication at the recommended dose had higher survival rates than those who took less than the recommended dose, according to a study appearing recently in the online journal PLOS ONE. Hydroxyurea is the only FDA-approved drug to treat the rare blood disorder.

For the study, researchers at the National Heart, Lung, and Blood Institute (NHLBI) and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) reviewed data from 383 patients treated or evaluated for sickle cell anemia by the National Institutes of Health between 2001 and 2010. With 66% of those taking hydroxyurea, only two-thirds of them—representing 44% of the overall group—were on doses high enough to fall within the recommended range. Yet patients taking the recommended dose were 64% less likely to die of sickle cell anemia compared with those not taking hydroxyurea—a survival benefit not observed in those taking less than the recommended dose.

Study authors point to previous research indicating that hydroxyurea is highly effective in managing the complications of sickle cell anemia. Their analysis suggests that many patients who take hydroxyurea should gradually increase their dosage to the recommended levels as tolerated, based upon the desired effect and adverse effects.

African Americans make up the majority of the 70,000 to 100,000 Americans who have sickle cell anemia, which can lead to complications, including organ damage and intense pain. Other groups affected by the disease include Hispanics, southern Europeans, Middle Easterners, or Asian Indians.

“Our data suggest that adults should be treated with the maximum tolerated hydroxyurea dose, ideally before organ damage occurs,” study authors concluded, calling for prospective studies to validate their findings.

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