Treatment: hydroxyurea (hydroxycarbamide: Hydrea, Siklos)
BioMG follows French guidelines. Adapt it to the guidelines and the tests available where you practise.
Myeloproliferative neoplasm (polycythaemia vera, essential thrombocythaemia): before starting
Laboratory tests
- FBC
- Serum creatinine with eGFR
- AST
- ALT
- Serum urate
- Serum β-hCG (woman of childbearing potential)if neededAbsence of pregnancy must be checked by a test before the first dose; hydroxycarbamide is contraindicated during pregnancy and breastfeeding [2].
- HIV serologyif needednon-French guidelineThe British national shared care protocol has the specialist carry out, before treatment, viral screening according to local policy, for example HIV and hepatitis B and C [3]. The French SmPC (RCP) does not request it, but reports pancreatitis and severe liver damage in HIV-infected patients also receiving antiretrovirals [2].
- Hepatitis B serologyif needednon-French guidelineThe British national shared care protocol has the specialist carry out, before treatment, viral screening according to local policy, for example HIV and hepatitis B and C [3]. The French SmPC (RCP) does not request it, but reports pancreatitis and severe liver damage in HIV-infected patients also receiving antiretrovirals [2].
- Hepatitis C serologyif needednon-French guidelineThe British national shared care protocol has the specialist carry out, before treatment, viral screening according to local policy, for example HIV and hepatitis B and C [3]. The French SmPC (RCP) does not request it, but reports pancreatitis and severe liver damage in HIV-infected patients also receiving antiretrovirals [2].
Myeloproliferative neoplasm: monitoring on treatment
At the frequency set by the haematologist (in the stable phase, every 6 to 8 weeks)
- FBC
Regularly, at the frequency set by the haematologist
- Serum creatinine with eGFR
- AST
- ALT
- Serum folate
- Serum urate (especially at the start of treatment)if neededHyperuricaemia from cell lysis, especially at the start of treatment, is to be prevented and then monitored during treatment [2]. Note: hydroxycarbamide falsely raises the enzymatic measurement of uric acid [2].
- Haptoglobinif neededSevere haemolytic anaemias have been reported: if anaemia persists, monitor haemolysis markers; confirmed haemolysis requires stopping treatment [2].
- Reticulocyte countif neededSevere haemolytic anaemias have been reported: if anaemia persists, monitor haemolysis markers; confirmed haemolysis requires stopping treatment [2].
- LDHif neededSevere haemolytic anaemias have been reported: if anaemia persists, monitor haemolysis markers; confirmed haemolysis requires stopping treatment [2].
Sickle cell disease (Siklos): before and during treatment
Before treatment
- FBC with reticulocyte count
- Serum creatinine with eGFR
- AST
- ALT
- GGT
- Bilirubin
- Serum β-hCG (woman of childbearing potential)if neededEffective contraception strongly recommended in women of childbearing potential, who must inform their doctor immediately in case of pregnancy [8].
- Fetal haemoglobin (to have the baseline value)if needednon-French guidelineThe American NHLBI panel (2014) asks for a quantitative measurement of fetal haemoglobin before hydroxyurea, if available, without the result influencing the decision to treat [9]. The European SmPC (RCP) cites its rise among the signs of response to treatment [8]: comparing requires a baseline value.
Once a month for the first 2 months (and at high dose), then every 2 months if stable
- FBC with reticulocyte count
Regularly
- Serum creatinine
- AST
- ALT
- Fetal haemoglobin (every 3 to 4 months, to assess response)if needednon-French guidelineThe American Droxia leaflet proposes this measurement every 3 to 4 months and looks for a doubling of the baseline value [10]. The NHLBI panel also follows fetal haemoglobin and MCV, but absence of a rise does not lead to stopping treatment [9]. The European SmPC (RCP) cites this indicator without setting a frequency [8].
Sources (11)
- Assurance maladie. Open Medic 2025 : nombre de consommants par substance active (ATC5), médicaments remboursés délivrés en officine de ville (fichier NB_2025_atc5). open-data-assurance-maladie.ameli.fr.
- ANSM, Base de données publique des médicaments. Résumé des caractéristiques du produit HYDREA 500 mg, gélule (hydroxycarbamide), rubriques 4.1 à 4.9 ; mise à jour du 29/09/2026, consulté le 12 octobre 2026.
- NHS, South West London Integrated Medicines Optimisation Committee (adaptation locale). National shared care protocol: hydroxycarbamide for myeloproliferative disorders and sickle cell disease for patients within adult services. Version 1.2, approuvée le 15 février 2023, révision prolongée en décembre 2025 jusqu'en février 2028.
- Barbui T, Tefferi A, Vannucchi AM, Passamonti F, Silver RT, Hoffman R, et al. Philadelphia chromosome-negative classical myeloproliferative neoplasms: revised management recommendations from European LeukemiaNet. Leukemia. 2018;32(5):1057-69.
- Food and Drug Administration (États-Unis). Hydroxyurea capsules, USP, prescribing information, Leading Pharma, version du 29 octobre 2024, rubriques 1 et 2.
- Lengfelder E, Baerlocher GM, Döhner K, Ernst T, Gisslinger H, Grießhammer M, Koschmieder S, et al. Polycythaemia Vera (PV). Leitlinie Onkopedia (DGHO), septembre 2023.
- Petrides PE, Baerlocher GM, Döhner K, Gisslinger H, Grießhammer M, Koschmieder S, Schwaab J, et al. Essentielle (oder primäre) Thrombozythämie (ET). Leitlinie Onkopedia (DGHO), décembre 2023.
- Agence européenne des médicaments. Siklos (hydroxycarbamide) : résumé des caractéristiques du produit (information produit EPAR, en français), rubriques 4.2 à 4.6 ; consulté le 12 octobre 2026.
- National Heart, Lung, and Blood Institute (États-Unis). Evidence-Based Management of Sickle Cell Disease: Expert Panel Report, 2014. Chapitre 5, protocole de consensus pour l'hydroxyurée.
- Food and Drug Administration (États-Unis). DROXIA (hydroxyurea) capsules, prescribing information, Waylis Therapeutics, version du 12 septembre 2025, rubriques 2 et 5.
- Hoferer A, Alashkar F, Cario H, Corbacioglu S, le Coutre P, Distelmaier L, Hegemann I, Kager L, Lobitz S, Schmugge Liner M, Sillaber C, Wörmann B, Dickerhoff R. Sichelzellkrankheiten. Leitlinie Onkopedia (DGHO), octobre 2024.