Hydroxycarbamide (Hydroxyurea)
Hydroxycarbamide (commonly known as hydroxyurea) is an antimetabolite antineoplastic agent. It is primarily used in veterinary medicine for the treatment of myeloproliferative disorders such as **polycythaemia vera** and **leukaemias**, as well as for **mast cell tumours** and as an adjunctive treatment for **canine meningiomas**. > **WARNING**: This is a cytotoxic drug. Strict safety and handling protocols must be followed to prevent human exposure. **Clinical Pearl:** Cats are significantly more sensitive to the myelosuppressive effects of hydroxycarbamide and require more intensive initial monitoring.
Mecanismo: Hydroxycarbamide inhibits the enzyme **ribonucleotide reductase** → prevents the conversion of ribonucleotides to deoxyribonucleotides → depletes the intracellular pool of precursors essential for **DNA synthesis and repair**. It is a cell-cycle specific agent acting primarily in the **S-phase**, but it may also arrest cells at the G1-S border.
Dosificación por especie
- Polycythaemia vera, chronic myeloid leukaemia, mast cell tumours, meningiomas · See Appendix for chemotherapy protocols · PO · variable · Reduce dosage frequency once in remission · Perform haematology initially weekly for one month, then every two weeks for one month, then monthly if tolerated.
- Polycythaemia vera, chronic myeloid leukaemia · See Appendix for chemotherapy protocols · PO · variable · Reduce dosage frequency once in remission · Haematology MUST be monitored weekly at the start of drug therapy due to greater risk of myelosuppression.
Las dosis son una referencia clínica para médicos veterinarios. Confirme siempre con la información vigente del producto y el paciente individual.
Vías de administración
Contraindicaciones
- Pre-existing bone marrow suppression
Efectos adversos
- Myelosuppression (dose-limiting)
- Nausea
- Vomiting
- Diarrhoea
- Anorexia
- Dysuria
- Stomatitis
- Sloughing of nails
- Alopecia
- Methaemoglobinaemia (in cats at high doses)
- Cardiovascular changes (increased diastolic BP/HR, decreased systolic BP)
Interacciones farmacológicas
- Other myelosuppressive agents · Increased risk of severe bone marrow suppression · major
Monitoreo
- Haematology (weekly for 1 month, then biweekly for 1 month, then monthly)
- Renal function parameters
- Blood pressure and ECG (due to potential cardiovascular effects)
Sobredosis
In cats, very high doses (>500 mg) have been reported to cause **methaemoglobinaemia**.
La referencia de fármacos de VetSheet está destinada a médicos veterinarios como apoyo a la decisión clínica; no sustituye el juicio profesional ni la información vigente del fabricante.