Hydrea

Action

Unknown. May inhibit enzyme necessary for DNA synthesis without disrupting RNA or protein synthesis.

Availability

Capsules: 200 mg, 300 mg, 400 mg, 500 mg

Indications and dosages

➣ Head and neck cancer; ovarian cancer; malignant melanoma

Adults: 60 to 80 mg/kg (2 to 3 g/m²) P.O. as a single daily dose q 3 days, or 20 to 30 mg/kg/day P.O. as a single dose. Begin therapy 7 days before radiation.

➣ Resistant chronic myelogenous leukemia

Adults: 20 to 30 mg/kg/day P.O. in one or two divided doses

➣ Sickle cell anemia

Adults and children: 15 mg/kg/day P.O. as a single dose. May increase by 5 mg/kg/day P.O. q 12 weeks, up to 35 mg/kg/day.

Off-label uses

• Thrombocythemia

• Human immunodeficiency virus

Contraindications

• Hypersensitivity to drug or tartrazine

• Bone marrow depression

• Severe anemia or thrombocytopenia

Precautions

Use cautiously in:

• renal or hepatic impairment

• obese patients

• females of childbearing age

• elderly patients.

Administration

• Provide frequent mouth care.

Adverse reactions

CNS: drowsiness, malaise, confusion, dizziness, headache

GI: nausea, vomiting, diarrhea, constipation, stomatitis, anorexia

GU: dysuria, hyperuricemia, infertility, renal tubular dysfunction

Hematologic: anemia, megaloblastosis, leukopenia, thrombocytopenia, bone marrow depression

Hepatic: hepatitis

Metabolic: hyperuricemia

Skin: alopecia, erythema, pruritus, rash, urticaria, exacerbation of post-radiation erythema

Other: chills, fever

Interactions

Drug-drug. Live-virus vaccines: decreased antibody response to vaccine, increased risk of adverse reactions

Myelosuppressants: additive bone marrow depression

Drug-diagnostic tests. Blood urea nitrogen, creatinine, uric acid: increased values

Hemoglobin, platelets, red blood cells, white blood cells: decreased values

Mean corpuscular volume: transient increase

Patient monitoring

• Assess CBC weekly.

• Closely monitor patient with renal or hepatic impairment. Check kidney and liver function tests often.

• Assess fluid status. Make sure patient drinks 10 to 12 glasses of water daily.

Patient teaching

• Advise patient to mark dates for drug doses, diagnostic tests, and treatments on calendar.

☞ Instruct patient to immediately report easy bruising, bleeding, unusual tiredness, or yellowing of skin or eyes.

• Tell patient to report such adverse effects as appetite loss, nausea, vomiting, oral lesions, constipation, diarrhea, confusion, dizziness, headache, and rash.

• Instruct female patient to use barrier contraception.

• Tell patient he will undergo regular blood testing to monitor drug effects.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.