• Sickle Cell Disease (SCD) – to reduce the frequency of painful crises and need for blood transfusions

Dose: 

  • Initial dose:Adults: 15 mg/kg/day orally,Children: 20 mg/kg/day and adjust every 8–12 weeks based on blood counts
  • Max dose: ~35 mg/kg/day
  • Chronic Myeloid Leukemia (CML)
  • Polycythemia Vera (PV)
  • Essential Thrombocythemia (ET)

Dose: 15–30 mg/kg/day orally, individualized based on counts and tolerance

  • Head and Neck Cancers (as a radiosensitizer, often with radiotherapy)

Dose:Used in combination with radiation therapy, dose varies (e.g., 80 mg/kg every 3 days), Always monitor blood counts regularly and adjust dosage to avoid severe myelosuppression.

  • Capsules: 200 mg, 300 mg, 400 mg, 500 mg
  • Tablets: 500 mg, 1 g (varies by manufacturer)
  • Taken orally once daily, preferably at the same time each day
  • Can be taken with or without food
  • Swallow whole (do not crush or open capsules)
  • Stay hydrated while on therapy
  • Class: Antimetabolite, ribonucleotide reductase inhibitor
  • Mechanism of Action:
    • Inhibits ribonucleotide reductase → halts DNA synthesis → cell cycle arrest in S-phase
    • In sickle cell disease: ↑ fetal hemoglobin (HbF) → ↓ sickling of RBCs, hemolysis, vaso-occlusion
  • Absorption: Well absorbed orally
  • Metabolism: Hepatic and extrahepatic
  • Elimination: Renal (dose adjustment needed in renal impairment)
  • Half-life: ~3–4 hours
  • Myelosuppression (neutropenia, anemia, thrombocytopenia)
  • GI upset: Nausea, vomiting, diarrhea
  • Skin and nail discoloration
  • Hyperpigmentation (hands, face, nails)
  • Fatigue
  • Fever
  • Pregnancy
  • Severe bone marrow suppression
  • Hypersensitivity to hydroxyurea
  • Caution in renal or hepatic impairment
  • Didanosine + Stavudine (in HIV): ↑ risk of hepatotoxicity, pancreatitis, and neuropathy
  • Other myelosuppressive agents: Additive hematologic toxicity
  • Live vaccines: Avoid due to immunosuppression

                                   Drug Status

Availability
Pregnancy
Breastfeeding
Schedule
BRAND NAME STRENGTH FORMULATION PACK SIZE MANUFACTURER DISTRIBUTOR
Hydrine 500mg Capsule 100’s Veteran Pharma Veteran Pharma
Hydrine 250mg Capsule 30’s Veteran Pharma Veteran Pharma
Hydroxycarbamide 500mg Capsule 100’s Sandoz GMBH Novartis Kenya
Hydroxyurea 500mg Tablet 100’s F.Hoffman-La Roche Surgipharm Ltd