Table 1.

Guideline for administering hydroxyurea

White blood cell (WBC) counts	Dose of hydroxyurea
5–10 × 109/L	0–-1 g/day
10–20 × 109/L	1.0–2.0 g/day
20–40 × 109/L	2.0–4.0 g/day
≥ 40 × 109/L	4.0 g/day