hydroxurea is an oral anti-metabolite medication used to Rx certain bone marrow disorders such as myeloproliferative diseases (polycythaemia rubra vera, essential thrombocytosis), sickle cell disease (SCD), CML (but now replaced by imatinib), systemic mastocytosis with associated hematological neoplasm(SM-AHN), and as a 2nd line agent in psoriasis
also known as hydroxycarbamide
endogenous in human blood plasma at concentrations of approximately 30 to 200 ng/ml
marketed in Australia as Hydrea
in patients with myeloproliferative diseases who are intolerant of hydroxyurea or fail to respond, a JAK 1/2 inhibitor such as ruxolitinib may be an option
Adult dosage
tablets are usually 500mg and should be should be handled with care and wash hands after touching them. People who are not taking this medicine should avoid touching it.
usual dose is 15mg/kg/day (in reality for adults this is 500mg/day for most as they should NOT be crushed or divided)
adjust if renal impairment
take with or after meals
in myeloproliferative diseases (usually those aged over 50yrs and prescribed and monitored monthly initially by a haematologist):
usual starting dose is 500mg / day and adjust as needed according to response - some may need one every two days, others may need increasing to 1000mg/day.
Mechanisms of action
decreases the production of deoxyribonucleotides via inhibition of the enzyme ribonucleotide reductase by scavenging tyrosyl free radicals as they are involved in the reduction of nucleoside diphosphates (NDPs)
causes production of reactive oxygen species in cells, leading to disassembly of replicative DNA polymerase enzymes and arresting DNA replication