HYDROXYUREA
| HYDROXYUREa (hye-drox'ee-yoo-ree-ah) Hydrea, Droxia Classifications: antineoplastic; antimetabolite; Therapeutic:antineoplastic; antimetabolite Pregnancy Category: D |
Availability
500 mg capsules
Action
A cell-cycle-phase antineoplastic agent; hydroxyurea causes an immediate inhibition of DNA synthesis by acting as an RNA reductase inhibitor, necessary for DNA synthesis but without interfering with the synthesis of RNA or protein.
Therapeutic Effect
Cytotoxic effect limited to tissues with high rates of cell proliferation. No cross resistance with other antineoplastics has been demonstrated.
Uses
Palliative treatment of metastatic melanoma, chronic myelocytic leukemia; recurrent metastatic, or inoperable ovarian cancer. Also used as adjunct to x-ray therapy for treatment of advanced primary squamous cell (epidermoid) carcinoma of head (excluding lip), neck, lungs.
Unlabeled Uses
Psoriasis; combination therapy with radiation of lung carcinoma; sickle cell anemia.
Contraindications
Pregnancy (category D), lactation, children, myelosuppression.
Cautious Use
Recent use of other cytotoxic drugs or irradiation; bone marrow depression; renal dysfunction; older adults; history of gout.
Route & Dosage
| Palliative Therapy Adult: PO 80 mg/kg q3d or 20–30 mg/kg/d Sickle Cell Anemia Adult: PO 15 mg/kg/d, may increase by 5 mg/kg/d (max: of 35 mg/kg/d or until toxicity develops) Renal Impairment Clcr 10–50 mL/min: administer 50% of dose; <10 mL/min: administer 20% of dose Hemodialysis: Administer dose after hemodialysis; no supplemental dose needed |
Administration
Oral- Open, mix with water, and give immediately when patient has difficulty swallowing capsule.
- Store in tightly covered container at 15°–30° C (59°–86° F) unless otherwise directed.
Adverse Effects (≥1%)
CNS: Rare: Headache, dizziness, hallucinations, convulsions. GI: Stomatitis, anorexia, nausea, vomiting, diarrhea, constipation. Hematologic: Bone marrow suppression (leukopenia, anemia, thrombocytopenia), megaloblastic erythropoiesis. Skin: Maculopapular rash, facial erythema, postirradiation erythema. Urogenital: Renal tubular dysfunction, elevated BUN, serum, creatinine levels, hyperuricemia. Body as a Whole: Fever, chills, malaise.Interactions
Drug: No clinically significant interactions established.Pharmacokinetics
Absorption: Readily absorbed from GI tract. Peak: 2 h. Distribution: Crosses blood–brain barrier. Metabolism: In liver. Elimination: As respiratory CO2 and as urea in urine.Nursing Implications
Assessment & Drug Effects
- Lab tests: Determine status of kidney, liver, and bone marrow function before and periodically during therapy; monitor hemoglobin, WBC, platelet counts at least once weekly.
- Interrupt therapy if WBC drops to 2500/mm3 or platelets to 100,000/mm3.
- Monitor I&O. Advise patients with high serum uric acid levels to drink at least 10–12 240 mL (8 oz) glasses of fluid daily to prevent uric acid nephropathy.
- Note: Patients with marked renal dysfunction may rapidly develop visual and auditory hallucinations and hematologic toxicity.
Patient & Family Education
- Note: Incidence of toxicity is as high as 66% with doses of 40 mg/kg body weight.
- Notify physician of fever, chills, sore throat, nausea, vomiting, diarrhea, loss of appetite, and unusual bruising or bleeding.
- Use barrier contraceptive during therapy. Drug is teratogenic.
Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; 
Canadian drug name; 
Prototype drug