Siklos (hydroxyurea) Disease Interactions

The use of hydroxyurea is contraindicated in patients with marked myelosuppression. Hydroxyurea induces myelosuppression, primarily leukopenia. Thrombocytopenia and anemia occur less frequently. Patients should be instructed to immediately report any signs or symptoms suggesting bone marrow suppression such as fever, sore throat, local infection, or bleeding. Close clinical monitoring of hematopoietic function is recommended. Hydroxyurea should not be administered if the white blood cell count falls below 2500/mm3 and/or the platelet count falls below 100,000/mm3, or in the presence of severe anemia.

Hydroxyurea is primarily eliminated by the kidney. Approximately 80% of urea is excreted in the urine as unchanged drug or urea. Patients with marked renal impairment (CrCl < 60 mL/min or ESRD) may be at increased risk of toxicity associated with administration of hydroxyurea. Therapy with hydroxyurea should be administered cautiously to patients with compromised renal function.

There are no data supporting specific guidance for hydroxyurea dosage adjustment in patients with hepatic impairment. Caution and close monitoring is advised in these patients.

Seizures have been noted very rarely during hydroxyurea therapy. Therapy with hydroxyurea should be administered cautiously in patients with seizure disorders.

Neurological symptoms such as disorientation or hallucinations have been reported very rarely during hydroxyurea therapy. Therapy with hydroxyurea should be administered cautiously to patients with or predisposed to neurological disorders.