Barriers to hydroxyurea (HU) use exist for children with sickle cell disease (SCD). Anecdotally, some parents report that their children struggle to swallow HU capsules. We hypothesized that difficulties in swallowing capsules and other forms of daily medication may be a barrier to pediatric HU use.


A self-administered survey of parents of children with SCD ages 5-17 years was conducted in pediatric SCD clinics at four different sites (see author affiliations). Parents submitted one survey for each eligible child. We assessed views on their child's medication regimen, including HU; how medications were swallowed; whether swallowing difficulties were perceived as barriers to medication adherence and whether children taking HU had fewer difficulties taking medication. Respondents were grouped by whether children were on HU therapy. Data were analyzed using descriptive statistics, chi square and Fisher exact tests.


A total of 122 adults completed the survey, with 27-35 surveys obtained from each site. Of survey respondents, 98% were parents and 95% reported being the child's primary caregiver. Half of all children were ages 8-13 years, and 23% were 7 or younger. Groups were evenly divided by whether children were taking HU (n=61 in both groups). There were no significant differences between groups regarding parent or child age, number of children living in the home or choice of the Spanish version of the survey. Parents of children in the group taking HU had a higher level of education (p=0.04). We found 24% of all parents thought that swallowing medications was “hard to do”. Most (85%) parents reported that swallowing difficulties did not preclude daily medication use, with no differences by HU use. All (98%) children could swallow liquid medication, with two thirds reported as able to do so by age 1. In contrast, 76% of children could swallow pills, with 40% able to do so by age 4. No differences by HU use were found in overall ability or age to swallow pills, although more in the HU group could swallow large pills (78.4 vs. 54.2%, p=0.03). No differences between groups were found in ability to swallow capsules. Across all age groups, 26.5% of children could not swallow capsules. Only 20% of all children could swallow capsules by age 4. Of children taking HU, 71.4% used the capsule form. Only 17% of those children open the capsules to mix with a liquid or soft food to aid in swallowing. Few (11%) children in both groups had received training for medication swallowing; most of their parents perceived the training as helpful to their child. While 96% of the children were prescribed medication, children taking HU were more likely than the others to be taking any medication (100 vs. 85%, p=0.001), and twice as likely to take medication on a daily basis (98.4 vs. 51.6%, p=0.001). Parents of children taking HU more often reported that their children took multiple medications (<0.001), including more pills daily (p=0.02). Children on HU had a medication regimen of more than once daily (61.7 vs. 28.6%, p<0.001).


Based on self-report, the majority of parents of children with SCD did not view medication swallowing as an impediment to daily use of medications, including HU. Children in the HU group reported less difficulty swallowing large pills, but were not different in their ability to ingest capsules, small pills or liquid medication. These data suggest that difficulty swallowing medication is not a barrier to HU use for most children. Nonetheless, a substantial proportion of children ages 5-17 cannot swallow capsules; children under 5 are especially challenged. Therefore, coaching for swallowing to improve HU uptake could be targeted to the modest proportion of children who need assistance. Moreover, a reliable source of liquid HU is still needed for children who cannot swallow capsules. Our findings also suggest that HU use is more likely in families committed to daily medication use and more complex medication schedules, or for children with medical needs requiring therapy beyond once daily HU. Clinicians should continue to educate families about the benefits of HU and address potential impediments such as swallowing HU capsules and complex medication regimens.

This study received support from NIH 1R21NR013745 (Green and Smaldone, PIs).


Off Label Use: Hydroxyurea for treating children with sickle cell disease is off-label use.

Author notes


Asterisk with author names denotes non-ASH members.