hydroxyurea 1000 MG Oral Tablet [Siklos]

INDICATIONS AND USAGE SIKLOS ® is indicated to reduce the frequency of painful crises and to reduce the need for blood transfusions in adult and pediatric patients, 2 years of age and older, with sickle cell anemia with recurrent moderate to severe painful crises SIKLOS is an antimetabolite, indicated to reduce the frequency of painful crises and to reduce the need for blood transfusions in adult and pediatric patients, 2 years of age and older, with sickle cell anemia with recurrent moderate to severe painful crises. ( 1 )

DOSAGE AND ADMINISTRATION Initial dose: 15 mg/kg orally once daily. Monitor the patient’s blood count every two weeks. (2.1) The dose may be increased by 5 mg/kg/day every 8 to 12 weeks until a maximum tolerated dose or 35 mg/kg/day is reached if blood counts are in an acceptable range. (2.1) The dose is not increased if blood counts are below the acceptable range and toxic. Discontinue XROMI until hematologic recovery if blood counts are considered toxic. Treatment may be resumed after reducing the dose by 2.5mg/kg/day to 5mg/kg/day from the dose associated with hematological toxicity. (2.1) Renal impairment: Reduce the dose of XROMI by 50% in patients with creatinine clearance less than 60 mL/min. (2.2 , 8.6 , 12.3) 2.1 Recommended Dosage The recommended XROMI dosage in pediatric patients aged 6 months and older is described in Table 1. Table 1. Dosing Recommendation Based on Blood Count Dosing Regimen Dose Dose modification criteria Monitoring parameters Initial Recommended dosing 15 mg/kg/day (rounded to nearest 10 mg) orally as a single dose once daily based on the patient’s actual body weight. Monitor the patient’s complete blood count (CBC) with differential and reticulocyte count every 2 weeks while adjusting dosage [see Warnings and Precautions (5.1) ] . Dosing Adjustment Based on Blood Counts in the acceptable range Increase dose 5 mg/kg/day every 8 to 12 weeks. Maximal dose: 35 mg/kg/day.* *Maximal dose is the highest dose that does not produce toxic blood counts over 24 consecutive weeks. Increase dose only if blood counts are in an acceptable range. Do not increase if myelosuppression occurs. Target Blood Counts Absolute neutrophil count (ANC) 1 to 3 x 10 9 /L and platelets at least 80 x 10 9 /L Dosing Adjustment Based on Blood Counts below acceptable range Do not increase dose. If blood counts are considered toxic, discontinue XROMI until hematologic recovery. Blood Counts Toxic Range ANC less than 1 x 10 9 /L Platelets less than 80 x 10 9 /L Hemoglobin 20% decrease from baseline or hemoglobin less than 4.5 g/dL Reticulocytes less than 80 x 10 9 /L if the hemoglobin concentration is less than 9 g/dL. Dosing after Hematologic Recovery If hematologic toxicity resolved within 1 week, restart at the same XROMI dose. If hematologic toxicity persisted for more than 1 week or occurred twice in a 3 month period, reduce dose by 5 mg/kg/day. Once a stable dose is established, monitor CBC with differential and reticulocyte count every 4 weeks for 2 months and then as clinically indicated. Caregivers must be able to follow directions regarding drug administration and their monitoring and care. If a dose of XROMI is missed at the scheduled time, the patient should take the missed dose as soon as possible once it is noticed, but only on the same day. If this is not possible, the patient should skip the dose and continue with the next dose as prescribed. The patient should not take two doses to make up for a missed dose. Fetal hemoglobin (HbF) levels may be used to evaluate the efficacy of XROMI in clinical use. Obtain HbF levels every three to four months. Monitor for an increase in HbF of at least two-fold over the baseline value. XROMI causes macrocytosis, which may mask the incidental development of folic acid deficiency. Prophylactic administration of folic acid is recommended. 2.2 Administration Instructions XROMI is for oral use. See Instructions for Use for details on preparation and administration of XROMI for oral solution. Do not shake. Two oral dosing syringes (one oral dosing syringe graduated to 3 mL and one oral dosing syringe graduated to 10 mL) are provided for accurate measurement of the prescribed dose of the oral solution. It is recommended that the healthcare professional advises the caregiver which oral dosing syringe to use to ensure that the correct volume is administered. The smaller 3 mL oral dosing syringe, marked from 0.5 mL to 3 mL, is for measuring doses of less than or equal to 3 mL. This oral dosing syringe should be recommended for doses less than or equal to 3 mL (each graduation of 0.1 mL contains 10 mg of hydroxyurea). The larger 10 mL oral dosing syringe, marked 1 mL to 10 mL, is for measuring doses of more than 3 mL. This oral dosing syringe should be recommended for doses greater than 3 mL (each graduation of 0.25 mL contains 25 mg of hydroxyurea). XROMI may be taken with or after meals at any time of the day but caregivers should standardize the method of administration and time of day. XROMI is a hazardous drug. Follow applicable special handling and disposal procedures [see Reference (15) ] . 2.3 Dosage Modifications in Renal Impairment Reduce the dose of XROMI by 50% in patients with creatinine clearance of less than 60 mL/min or with end-stage renal disease (ESRD) [see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3) ] . Creatinine clearance were obtained using 24-hour urine collection. Table 2. Creatinine Clearance Creatinine Clearance (mL/min) Recommended XROMI Initial Dose Greater than or equal to 60 15 mg/kg once daily Less than 60 or ESRD* 7.5 mg/kg once daily * On dialysis days, administer XROMI to patients with ESRD following hemodialysis Monitor the hematologic parameters closely in these patients.

WARNINGS AND PRECAUTIONS Myelosuppression: Do not give if bone marrow function is markedly depressed. Monitor blood counts at baseline and throughout treatment. Interrupt treatment and reduce dose as necessary. (5.1) Hemolytic anemia: Monitor blood counts throughout treatment. If hemolysis persists, discontinue Hydroxyurea. (5.2) Malignancies: Advise protection from sun exposure and monitor for secondary malignancies. ( 5.3) Embryo-Fetal toxicity: Can cause fetal harm. Advise of potential risk to a fetus and use of effective contraception. ( 5.4 , 8.1 , 8.3 ) Vasculitic toxicities: Discontinue hydroxyurea and initiate treatment if this occurs. (5.5) Live Vaccinations: Avoid live vaccine use in a patient taking hydroxyurea capsules. (5.6) Risks with concomitant use of antiretroviral drugs: Pancreatitis, hepatotoxicity, and neuropathy have occurred. Monitor for signs and symptoms in patients with HIV infection using antiretroviral drugs; discontinue hydroxyurea capsules and implement treatment. (5.7) Radiation recall: Monitor for skin erythema in patients who previously received radiation and manage symptomatically. (5.8) 5.1 Myelosuppression s ion Hydroxyurea causes severe myelosuppression. Treatment with hydroxyurea should not be initiated if bone marrow function is markedly depressed. Bone marrow suppression may occur, and leukopenia is generally its first and most common manifestation. Thrombocytopenia and anemia occur less often and are seldom seen without a preceding leukopenia. Bone marrow depression is more likely in patients who have previously received radiotherapy or cytotoxic cancer chemotherapeutic agents; use hydroxyurea cautiously in such patients. Evaluate hematologic status prior to and during treatment with hydroxyurea capsules. Provide supportive care and modify dose or discontinue hydroxyurea as needed. Recovery from myelosuppression is usually rapid when therapy is interrupted. 5.2 Hemolytic Anemia Cases of hemolytic anemia in patients treated with hydroxyurea for myeloproliferative diseases have been reported [see Adverse Reactions (6.1) ]. Patients who develop acute jaundice or hematuria in the presence of persistent or worsening of anemia should have laboratory tests evaluated for hemolysis (e.g., measurement of serum lactate dehydrogenase, haptoglobin, reticulocyte, unconjugated bilirubin levels, urinalysis, and direct and indirect antiglobulin [Coombs] tests). In the setting of confirmed diagnosis of hemolytic anemia and in the absence of other causes, discontinue hydroxyurea. 5.3 Malignancies Hydroxyurea is a human carcinogen. In patients receiving long-term hydroxyurea for myeloproliferative disorders, secondary leukemia has been reported. Skin cancer has also been reported in patients receiving long-term hydroxyurea. Advise protection from sun exposure and monitor for the development of secondary malignancies. 5.4 Embryo-Fetal Toxicity Based on the mechanism of action and findings in animals, hydroxyurea can cause fetal harm when administered to a pregnant woman. Hydroxyurea was embryotoxic and teratogenic in rats and rabbits at doses 0.8 times and 0.3 times, respectively, the maximum recommended human daily dose on a mg/m 2 basis. Advise pregnant women of the potential risk to a fetus [see Use in Specific Populations (8.1) ]. Advise females of reproductive potential to use effective contraception during and after treatment with hydroxyurea capsules for at least 6 months after therapy. Advise males of reproductive potential to use effective contraception during and after treatment with hydroxyurea capsules for at least 1 year after therapy [see Use in Specific Populations (8.1 , 8.3) ]. 5.5 Vasculitic Toxicities Cutaneous vasculitic toxicities, including vasculitic ulcerations and gangrene, have occurred in patients with myeloproliferative disorders during therapy with hydroxyurea. These vasculitic toxicities were reported most often in patients with a history of, or currently receiving, interferon therapy. If cutaneous vasculitic ulcers occur, institute treatment and discontinue hydroxyurea capsules. 5.6 Live Vaccinations Avoid use of live vaccine in patients taking hydroxyurea capsules. Concomitant use of hydroxyurea capsules with a live virus vaccine may potentiate the replication of the virus and/or may increase the adverse reaction of the vaccine because normal defense mechanisms may be suppressed by hydroxyurea capsules. Vaccination with live vaccines in a patient receiving hydroxyurea capsules may result in severe infection. Patient’s antibody response to vaccines may be decreased. Consider consultation with a specialist. 5.7 Risks with Concomitant Use of Antiretroviral Drugs Pancreatitis, hepatotoxicity, and peripheral neuropathy have occurred when hydroxyurea was administered concomitantly with antiretroviral drugs, including didanosine and stavudine [see Drug Interactions (7.1) ]. 5.8 Radiation Recall Patients who have received irradiation therapy in the past may have an exacerbation of post-irradiation erythema. Monitor for skin erythema in patients who previously received radiation and manage symptomatically. 5.9 Macrocytosis Hydroxyurea capsules may cause macrocytosis, which is self-limiting, and is often seen early in the course of treatment. The morphologic change resembles pernicious anemia, but is not related to vitamin B 12 or folic acid deficiency. This may mask the diagnosis of pernicious anemia. Prophylactic administration of folic acid is recommended. 5.10 Pulmonary Toxicity Interstitial lung disease including pulmonary fibrosis, lung infiltration, pneumonitis, and alveolitis/allergic alveolitis (including fatal cases) have been reported in patients treated for myeloproliferative neoplasm. Monitor patients developing pyrexia, cough, dyspnea, or other respiratory symptoms frequently, investigate and treat promptly. Discontinue hydroxyurea and manage with corticosteroids [ see Adverse Reactions (6.1) ]. 5.11 Laboratory Test Interference Interference with Uric Acid, Urea, or Lactic Acid Assays is possible, rendering falsely elevated results of these in patients treated with hydroxyurea [see Drug Interactions (7.2) ]. Hydroxyurea may falsely elevate sensor glucose results from certain continuous glucose monitoring (CGM) systems and may lead to hypoglycemia if sensor glucose results are relied upon to dose insulin. If a patient using a CGM is to be prescribed hydroxyurea, consult with the CGM prescriber about alternative glucose monitoring methods [see Drug Interactions (7.2) ]. 5.1 Myelosuppression s ion Hydroxyurea causes severe myelosuppression. Treatment with hydroxyurea should not be initiated if bone marrow function is markedly depressed. Bone marrow suppression may occur, and leukopenia is generally its first and most common manifestation. Thrombocytopenia and anemia occur less often and are seldom seen without a preceding leukopenia. Bone marrow depression is more likely in patients who have previously received radiotherapy or cytotoxic cancer chemotherapeutic agents; use hydroxyurea cautiously in such patients. Evaluate hematologic status prior to and during treatment with hydroxyurea capsules. Provide supportive care and modify dose or discontinue hydroxyurea as needed. Recovery from myelosuppression is usually rapid when therapy is interrupted. 5.2 Hemolytic Anemia Cases of hemolytic anemia in patients treated with hydroxyurea for myeloproliferative diseases have been reported [see Adverse Reactions (6.1) ]. Patients who develop acute jaundice or hematuria in the presence of persistent or worsening of anemia should have laboratory tests evaluated for hemolysis (e.g., measurement of serum lactate dehydrogenase, haptoglobin, reticulocyte, unconjugated bilirubin levels, urinalysis, and direct and indirect antiglobulin [Coombs] tests). In the setting of confirmed diagnosis of hemolytic anemia and in the absence of other causes, discontinue hydroxyurea. 5.3 Malignancies Hydroxyurea is a human carcin

CONTRAINDICATIONS XROMI is contraindicated in patients: who have demonstrated a previous hypersensitivity to hydroxyurea or any other component of its formulation. [see Adverse Reactions (6) ] . In patients who have demonstrated a previous hypersensitivity to hydroxyurea or any other component of its formulation. (4)

CLINICAL PHARMACOLOGY 12.1 Mechanism of Action The precise mechanism by which hydroxyurea produces its antineoplastic effects cannot, at present, be described. However, the reports of various studies in tissue culture in rats and humans lend support to the hypothesis that hydroxyurea causes an immediate inhibition of DNA synthesis by acting as a ribonucleotide reductase inhibitor, without interfering with the synthesis of ribonucleic acid or of protein. This hypothesis explains why, under certain conditions, hydroxyurea may induce teratogenic effects. Three mechanisms of action have been postulated for the increased effectiveness of concomitant use of hydroxyurea therapy with irradiation on squamous cell (epidermoid) carcinomas of the head and neck. In vitro studies utilizing Chinese hamster cells suggest that hydroxyurea (1) is lethal to normally radioresistant S-stage cells, and (2) holds other cells of the cell cycle in the G1 or pre-DNA synthesis stage where they are most susceptible to the effects of irradiation. The third mechanism of action has been theorized on the basis of in vitro studies of HeLa cells. It appears that hydroxyurea, by inhibition of DNA synthesis, hinders the normal repair process of cells damaged but not killed by irradiation, thereby decreasing their survival rate; RNA and protein syntheses have shown no alteration. 12.3 Pharmacokinetics Absorption Following oral administration of hydroxyurea capsules, hydroxyurea reaches peak plasma concentrations in 1 to 4 hours. Mean peak plasma concentrations and AUCs increase more than proportionally with increase of dose. There are no data on the effect of food on the absorption of hydroxyurea. Distribution Hydroxyurea distributes throughout the body with a volume of distribution approximating total body water. Hydroxyurea concentrates in leukocytes and erythrocytes. Metabolism Up to 60% of an oral dose undergoes conversion through saturable hepatic metabolism and a minor pathway of degradation by urease found in intestinal bacteria. Excretion In patients with sickle cell anemia, the mean cumulative urinary recovery of hydroxyurea was about 40% of the administered dose. Specific Populations Renal Impairment The effect of renal impairment on the pharmacokinetics of hydroxyurea was assessed in adult patients with sickle cell disease and renal impairment. Patients with normal renal function (creatinine clearance [CrCl] >80 mL/min), mild (CrCl 50 to 80 mL/min), moderate (CrCl = 30-<50 mL/min), or severe (<30 mL/min) renal impairment received a single oral dose of 15 mg/kg hydroxyurea. Patients with ESRD received two doses of 15 mg/kg separated by 7 days; the first was given following a 4-hour hemodialysis session, the second prior to hemodialysis. The exposure to hydroxyurea (mean AUC) in patients with CrCl <60 mL/min and those with ESRD was 64% higher than in patients with normal renal function (CrCl >60 mL/min). Reduce the dose of hydroxyurea capsules when it is administered to patients with creatinine clearance of <60 mL/min or with ESRD following hemodialysis [see Dosage and Administration (2.3 ) and Use in Specific Populations (8.6) ]. 12.1 Mechanism of Action The precise mechanism by which hydroxyurea produces its antineoplastic effects cannot, at present, be described. However, the reports of various studies in tissue culture in rats and humans lend support to the hypothesis that hydroxyurea causes an immediate inhibition of DNA synthesis by acting as a ribonucleotide reductase inhibitor, without interfering with the synthesis of ribonucleic acid or of protein. This hypothesis explains why, under certain conditions, hydroxyurea may induce teratogenic effects. Three mechanisms of action have been postulated for the increased effectiveness of concomitant use of hydroxyurea therapy with irradiation on squamous cell (epidermoid) carcinomas of the head and neck. In vitro studies utilizing Chinese hamster cells suggest that hydroxyurea (1) is lethal to normally radioresistant S-stage cells, and (2) holds other cells of the cell cycle in the G1 or pre-DNA synthesis stage where they are most susceptible to the effects of irradiation. The third mechanism of action has been theorized on the basis of in vitro studies of HeLa cells. It appears that hydroxyurea, by inhibition of DNA synthesis, hinders the normal repair process of cells damaged but not killed by irradiation, thereby decreasing their survival rate; RNA and protein syntheses have shown no alteration. 12.3 Pharmacokinetics Absorption Following oral administration of hydroxyurea capsules, hydroxyurea reaches peak plasma concentrations in 1 to 4 hours. Mean peak plasma concentrations and AUCs increase more than proportionally with increase of dose. There are no data on the effect of food on the absorption of hydroxyurea. Distribution Hydroxyurea distributes throughout the body with a volume of distribution approximating total body water. Hydroxyurea concentrates in leukocytes and erythrocytes. Metabolism Up to 60% of an oral dose undergoes conversion through saturable hepatic metabolism and a minor pathway of degradation by urease found in intestinal bacteria. Excretion In patients with sickle cell anemia, the mean cumulative urinary recovery of hydroxyurea was about 40% of the administered dose. Specific Populations Renal Impairment The effect of renal impairment on the pharmacokinetics of hydroxyurea was assessed in adult patients with sickle cell disease and renal impairment. Patients with normal renal function (creatinine clearance [CrCl] >80 mL/min), mild (CrCl 50 to 80 mL/min), moderate (CrCl = 30-<50 mL/min), or severe (<30 mL/min) renal impairment received a single oral dose of 15 mg/kg hydroxyurea. Patients with ESRD received two doses of 15 mg/kg separated by 7 days; the first was given following a 4-hour hemodialysis session, the second prior to hemodialysis. The exposure to hydroxyurea (mean AUC) in patients with CrCl <60 mL/min and those with ESRD was 64% higher than in patients with normal renal function (CrCl >60 mL/min). Reduce the dose of hydroxyurea capsules when it is administered to patients with creatinine clearance of <60 mL/min or with ESRD following hemodialysis [see Dosage and Administration (2.3 ) and Use in Specific Populations (8.6) ].