Hydroxyurea for people with sickle cell disease

Haemoglobin is the substance within the red blood cells that carries oxygen around the body. Sickle cell disease (SCD) is an inherited genetic disorder where there are problems with the haemoglobin. Crystals form in the red blood cells and block the blood flow. This causes pain and organ damage. Fetal haemoglobin stops crystals forming in the sickle haemoglobin within the red blood cell. So, raising the fetal haemoglobin level in people with SCD can reduce the effects of the disease. The drug hydroxyurea is used to raise fetal haemoglobin. We looked for studies which compared hydroxyurea to placebo for longer than one month. The review includes two studies with 324 people. One study is waiting to be assessed. We were only able to analyse data from one study which lasted two years. This study favoured hydroxyurea compared with placebo for the outcomes: annual crisis rate; use of transfusions; and life-threatening complications. Both studies described the expected rise in fetal haemoglobin. No serious adverse effects were reported from either study. We conclude that hydroxyurea can raise fetal haemoglobin levels in adults with SCD without any adverse effects.

Authors' conclusions: 

While hydroxyurea appears both effective and safe in severely affected SS adults over a two-year period; further studies are required to elucidate its role in other patient groups and for other conditions.

Read the full abstract...

Sickle cell disease is one of the most common inherited diseases worldwide. It is associated with lifelong morbidity and a reduced life expectancy. Hydroxyurea, an oral chemotherapeutic drug, is expected to ameliorate some of the clinical problems of sickle cell disease, in particular that of pain, by raising fetal haemoglobin.


To assess the effects of hydroxyurea therapy in people with sickle cell disease (all types), of any age, regardless of setting.

Search strategy: 

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Register, comprising of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.

Date of the most recent search: 12 May 2010.

Selection criteria: 

All randomised or quasi-randomised controlled trials comparing the use of hydroxyurea for one month or longer with placebo, standard therapy or other interventions for the treatment of people with sickle cell disease.

Data collection and analysis: 

Three authors independently assessed study quality and extracted data from the two included studies.

Main results: 

Two studies found by the searches, which reported results from a total of 324 adults and children, were suitable for inclusion in the review. From the data provided in the published reports, only one study (the MSH study to the United States of America) could be analysed. This study showed marked differences in favour of hydroxyurea treatment as compared with placebo in terms of annual crisis rate, use of transfusions, and life-threatening complications (in particular, acute sickle chest syndrome). Both studies documented the expected rise in fetal haemoglobin. No serious adverse effects were reported from either study.