Concurrent use of hydroxyurea and deferasirox in Californians with sickle cell disease

When patients with sickle cell disease have appropriate indications, they can be prescribed hydroxyurea (HU) and deferasirox (DFX) concurrently despite little knowledge about how the two medications interact. We wished to analyze whether there was evidence of adverse interaction between HU and DFX when taken simultaneously and hypothesized that those who took both drugs together had similar clinical complications when compared to those who took only one or neither drug.

We conducted this retrospective cohort investigation between 2009 and 2016 of persons with SCD in the California Sickle Cell Data Collection Program, a validated database of Californians with SCD a statewide. People in the database who took HU and DFX simultaneously for at least 3 months as compared to those who took either HU or DFX alone or to matched persons who took neither drug were eligible.

We identified 104 people who were prescribed both HU and DFX concurrently, 877 who were prescribed HU only, and 314 who were prescribed DFX only during the study period. We identified 416 matched controls who took neither HU nor DFX. People who took both HU and DFX concurrently had similar rates of ED and inpatient encounters and had similar rates and distribution of adverse effects compared to those who took either HU or DFX alone or took neither drug.

Three months of concurrent use of DFX and HU appears safe, but further studies are required to better understand the safety and effectiveness of this medication combination. (Funded by CDC, CDC Foundation, and others).