Indications for starting hydroxyurea therapy: both of the following:
(1) adolescent or adult
(2) one or more of the following
(2a) frequent episodes of pain
(2b) history of acute chest pain or other serious vaso-occlusive complication
(2c) severe symptomatic anemia
Indications to continue hydroxyurea therapy:
(1) with history of frequent episodes of pain: reduction in pain episodes
(2) with history of severe anemia: increase in hemoglobin
(3) increase in percent hemoglobin F and/or MCV
(4) acceptable myelotoxicity, with absolute neutrophil count >= 2,000 per µL and platelet count >= 80,000 per µL
where:
• MCV can serve as a surrogate marker for hemoglobin F.
