title: Nitric Oxide Metabolites in Sickle Cell Anemia Patients after Oral Administration of Hydroxyurea; Hemoglobinopathy.
abstract: The mechanism of action of hydroxyurea (HU) in decreasing the frequency of pain crisis in sickle cell disease (SCD) has not been fully elucidated. In vitro and in vivo studies suggest that nitric oxide (NO), a potent vasodilator, may partly be responsible for the beneficial effect of HU. This study was designed to determine the effect of oral administration of HU on plasma levels of NO metabolites (NO(x) ) in sickle cell patients (SCP). The results indicate that during steady-state plasma levels of NO(x) were significantly higher in HU-treated patients compared to non HU-treated patients or normal controls (p <.05). In five inpatients in mild pain plasma levels of NO(x) increased significantly after 2 h of HU administration (p <.05); however, in three inpatients in persistent pain with significantly lower baseline NO(x) there was a minimal NO(x) response to HU at 2 h (p <.01). These observations indicate that HU administration is associated with the production of NO in some SCP, but that further study of the pharmacodynamics of this effect is necessary.
authors.affiliation: Departments of Anesthesiology, Internal Medicine, and Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, DC.
authors.forename: Masoud
authors.initials: M
authors.lastname: Nahavandi
authors.forename: Melville Q.
authors.initials: MQ
authors.lastname: Wyche
authors.forename: Elliott
authors.initials: E
authors.lastname: Perlin
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Tavakkoli
authors.forename: Oswaldo
authors.initials: O
authors.lastname: Castro