Low molecular weight organic molecule. No reports on CYP-related interactions despite years of use. Side effects such as nausea and vomiting may be potentially porphyrinogenic through reduction in caloric intake.

Hydroxycarbamide (also called hydroxyurea) is a derivative of urea. Contains one secondary aminogroup.

Hydroxycarbamide is an antineoplastic agent used in the treatment of chronic myeloic leucemia, polycytemia vera and primary (essential) thrombocythaemia. It is administered orally. Common adverse reactions of hydroxycarbamide that can be confused with an acute porphyric attack are nausea, vomiting, obstipation and diarrhoea. Side effects such as nausea and vomiting may be potentially porphyrinogenic through reduction in caloric intake.

Up to 50 % of hydroxycarbamide is metabolized in the liver, however, the precise metabolic pathways have not been determined. Excreted in urine as unchanged drug and metabilites. Some is excreted as carbon dioxide by the lungs. Crosses the blood-brain barrier. CYP Interactions with CYP-metabolism of other drugs not stated. One study found that hydroxyurea had no inhibitory effect on the biotransformation of imatinib (i.e. that it did not inhibit CYP3A4) (Oostendorp, 2007). Not listed as CYP-inducer or CYP-inhibitor.

One report of uneventful use of hydroxyurea in 16 year old woman with PV (Samuels, 1984).

Uneventful use reported in 1 patient with acute porphyria.