Dosage and Dosage
- The dosage of hydroxyurea varies depending on the condition being treated.
- For adults with sickle cell anemia, the typical starting dose is 15 mg/kg/day, taken orally as a single daily dose.
- Dosage adjustments may be made based on the individual’s response and tolerance to the medication.
- Pediatric dosages are calculated based on body surface area and are typically lower than adult dosages.
Frequency
- Hydroxyurea is usually administered once daily.
- The frequency and duration of treatment may vary depending on the condition being treated and the individual’s response to therapy.
Route of Administration (ROA)
- Hydroxyurea is administered orally, usually as a tablet or capsule.
Mechanism of Action (MOA)
- Hydroxyurea works by inhibiting the enzyme ribonucleotide reductase, which is involved in DNA synthesis.
- By inhibiting DNA synthesis, hydroxyurea prevents the proliferation of certain cells, such as those involved in sickle cell disease or certain types of cancer.
Pharmacokinetics (PK)
- Hydroxyurea is well absorbed after oral administration, with peak plasma concentrations reached within 1 to 4 hours.
- It is primarily metabolized by the liver and excreted renally.
- The half-life of hydroxyurea is approximately 2 to 3 hours.
Pharmacodynamics (PD)
- The exact pharmacodynamics of hydroxyurea are not fully understood but are related to its effects on DNA synthesis and cell proliferation.
Pathophysiology
- Hydroxyurea has several mechanisms of action, including:
- Increasing fetal hemoglobin levels in patients with sickle cell disease, which helps prevent sickle cell crises.
- Inhibiting DNA synthesis and cell proliferation in certain types of cancer cells, leading to tumor regression.
Indications
- Hydroxyurea is indicated for the treatment of:
- Sickle cell anemia to reduce the frequency of painful crises and acute chest syndrome.
- Certain types of cancer, including chronic myeloid leukemia, certain types of melanoma, and certain types of solid tumors.
Contraindications
- Hydroxyurea is contraindicated in individuals who have demonstrated a previous hypersensitivity reaction to the drug or any of its components.
- It is also contraindicated in individuals with severe bone marrow suppression or severe renal or hepatic impairment.
Drug Interactions
- Hydroxyurea may interact with certain medications, including:
- Didanosine (increased risk of toxicity)
- Live vaccines (increased risk of adverse effects)
- Myelosuppressive agents (increased risk of bone marrow suppression)
Precautions
- Before initiating hydroxyurea therapy, healthcare providers should assess renal and hepatic function, as well as baseline blood counts.
- Patients should be monitored regularly for signs of bone marrow suppression, including leukopenia, thrombocytopenia, and anemia.
- Hydroxyurea should be used with caution in patients with renal or hepatic impairment and in pregnant or breastfeeding women.
Medication Information and Guidelines
| Question | Answer |
|---|---|
| Purpose of taking this medication | Hydroxyurea is used to treat sickle cell anemia by reducing the frequency of painful crises and acute chest syndrome. It is also used in the treatment of certain types of cancer, including chronic myeloid leukemia, certain types of melanoma, and certain types of solid tumors. |
| How am I supposed to use this medicine? | Hydroxyurea is typically taken orally as a tablet or capsule, once daily. The dosage may vary depending on the condition being treated and individual response to therapy. |
| Other reasons people might use this medication | Hydroxyurea may also be used off-label for conditions such as essential thrombocythemia and myeloproliferative disorders. |
| Specific precautions | Patients should be monitored regularly for signs of bone marrow suppression, including leukopenia, thrombocytopenia, and anemia. Renal and hepatic function should be assessed before initiating therapy. Use with caution in patients with renal or hepatic impairment and in pregnant or breastfeeding women. |
| Dietary changes | There are no specific dietary changes required while taking hydroxyurea. |
| What to do if I forget to take a dose | If a dose of hydroxyurea is missed, it should be taken as soon as remembered unless it is almost time for the next scheduled dose. In that case, the missed dose should be skipped, and the regular dosing schedule should be resumed. |
| Possible side effects | Common side effects of hydroxyurea include gastrointestinal disturbances, such as nausea, vomiting, diarrhea, and loss of appetite. Bone marrow suppression, including leukopenia, thrombocytopenia, and anemia, can also occur. Other side effects may include skin rash, fever, and hair loss. |
| Storage and disposal | Hydroxyurea should be stored at room temperature away from moisture and heat. Keep the medication in its original container with the lid tightly closed. Unused or expired medication should be disposed of properly according to local regulations. |
| What to do in case of overdose or emergency situation | In case of overdose, seek immediate medical attention. Symptoms of overdose may include severe nausea, vomiting, diarrhea, and bone marrow suppression. Emergency medical services should be contacted if any signs of an allergic reaction, such as difficulty breathing or swelling of the face or throat, occur. |
This table provides a concise summary of the key information regarding the use of hydroxyurea, including its purpose, dosage, precautions, side effects, and what to do in case of missed doses or emergencies.