Hydroxyurea (active ingredient hydroxycarbamide) is an oral chemotherapy agent classified as an oncology support medication. It is supplied as a 500 mg pill and is prescribed by a qualified healthcare provider. In Hong Kong, hydroxyurea is a prescription-only product regulated by the Department of Health and the Hospital Authority.
The drug is used to modify disease processes in certain blood-related conditions and certain cancers. It is not an over-the-counter medication and should only be taken under medical supervision.
Hydroxyurea interferes with the synthesis of DNA by inhibiting the enzyme ribonucleotide reductase. This enzyme is essential for converting ribonucleotides to deoxyribonucleotides, the building blocks of DNA. By limiting the supply of deoxyribonucleotides, hydroxyurea slows the proliferation of rapidly dividing cells, such as malignant white-blood cells and abnormal erythrocytes in sickle-cell disease.
Key pharmacologic points:
By reducing the number of sickled red cells and decreasing leukocyte counts, hydroxyurea improves oxygen delivery and mitigates complications in sickle-cell disease and certain leukemias.
Hydroxyurea is approved in many jurisdictions, including Hong Kong, for the following indications:
These uses are supported by regulatory approvals and clinical guidelines. Hydroxyurea is not indicated for solid tumors, non-malignant infections, or routine pain management.
All dosing decisions must be individualized by the treating physician, taking into account weight, organ function, disease severity, and concomitant medications.
Regular follow-up visits with a hematologist or oncologist ensure that dosing remains optimal and safe.
This article provides educational information about Hydroxyurea and is not a substitute for professional medical advice. Treatment decisions, including use for unapproved indications, must be made under the guidance of a qualified healthcare provider. The content is intended for informational purposes and does not constitute medical recommendations. Always consult a physician before starting, stopping, or changing any medication regimen.
Hydroxyurea is occasionally employed in pediatric oncology protocols for specific leukemias, but its use is highly protocol-dependent and requires specialist oversight. Dose calculations are weight-based, and close laboratory monitoring is mandatory.
If a dose is missed and the next scheduled dose is more than 12 hours away, take the missed tablet as soon as you remember. Do not double the dose. Keep a supply of the medication in your carry-on luggage and inform customs that it is a prescription drug.
Most vitamins do not interfere with hydroxyurea, but certain supplements that affect bone-marrow function (e.g., high-dose folic acid) should be discussed with your provider, as they may mask blood-count changes.
In Hong Kong, generic hydroxyurea tablets are often imprinted with “500 MG” and the manufacturer's logo. Imprint details can vary by supplier, so verify with your pharmacist.
Hydroxyurea is a solid pill, not a liquid, so it does not fall under liquid restrictions. Carry it in its original labeled container and have a copy of the prescription available if requested.
HbF levels typically begin to increase within 2-4 weeks of starting hydroxyurea, with maximal elevations observed after 3-6 months of stable dosing.
No specific foods must be avoided, but maintaining a balanced diet supports overall blood-cell health. Excessive alcohol may exacerbate hematologic toxicity and should be limited.
After a dose reduction, CBC should be repeated within 1-2 weeks to ensure recovery of blood counts before considering further adjustments.
Mild hepatic impairment does not usually require dose changes, but liver function tests should be monitored regularly. Severe liver disease may necessitate dose reduction.
It is best to keep the tablets in a cool, dry place away from humidity and heat; a bathroom cabinet may be too humid. A bedroom drawer or kitchen cabinet at room temperature is preferable.
