Hydroxyurea 500 mg Capsule, 100-count
🆔 Identity & classification
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🏷️ RxNorm drug class
This medicine belongs to the Antimetabolite class.
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🏭 Manufacturer & labeler
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🩺 Clinical
Hydroxyurea (Hydrea) is used alone or with other medications or radiation therapy to treat a certain type of chronic myelogenous leukemia (CML; a type of cancer of the white blood cells) and certain types of head and neck cancer (including cancer of the mouth, cheek, tongue, throat, tonsils, and sinuses). Hydroxyurea (Droxia, Siklos) is used to reduce the frequency of painful crises and reduce the need for blood transfusions in adults and children 2 years of age and older with sickle cell anemia (an inherited blood disorder in which the red blood cells are abnormally shaped [shaped like a sick...
Read the full MedlinePlus article ↗- It's actually both, depending on the specific product. Droxia, Siklos, and Xromi are each approved to reduce the painful crises and blood transfusion needs in sickle cell anemia. H...
- What exactly is hydroxyurea used for — is it a cancer drug or a sickle cell drug?
- Very regularly — typically every two weeks while your dose is being adjusted. Hydroxyurea can lower your white blood cell and platelet counts, so monitoring is built into the treat...
- How often will I need blood tests while I'm on this medication?
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🧪 Inactive Ingredients / Excipients
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UNII 5138Q19F1X
Ammonia is a colorless gas made from nitrogen and hydrogen. It's used in medicines as a pH buffer to maintain the correct acidity level and help keep the product stable.
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A synthetic yellow dye used to color medicines. It helps make tablets, capsules, and liquids visually distinct so patients can easily identify their medication.
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D&C Yellow No. 10 Aluminum Lake is a yellow colorant made by combining a dye with aluminum salts. It's used in medicines to add color for product identification and visual appeal.
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FD&C Blue No. 1 is a synthetic blue dye approved for use in foods and medicines. It serves as a colorant to give the medication its distinctive appearance and help with product identification.
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FD&C Blue No. 1 Aluminum Lake is a blue colorant made by combining FD&C Blue No. 1 dye with aluminum salts. It is used to color tablets, capsules, and other medicines for easy identification and appearance.
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A synthetic blue dye combined with aluminum to create a stable colorant. It's used in medicines and supplements to add blue color or create specific shades for product identification and appearance.
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A synthetic red dye used to color medications and make them easier to identify. It serves as a colorant in tablets, capsules, and liquid formulations.
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Red 40 Lake is a synthetic colorant made by combining Red 40 dye with aluminum hydroxide. It's used to give tablets, capsules, and other medicines a red or pink color for identification and appearance.
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A dark iron oxide compound that gives medicines their black or dark color. It's used as a colorant in tablets and capsules to help identify the product and make it visually distinctive.
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Gelatin is a protein derived from animal collagen, commonly used in medicines as a gelling agent and capsule material. It helps create soft or hard capsule shells that hold and release medication, and can also thicken liquid formulations.
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UNII 70097M6I30
Magnesium stearate is a salt made from magnesium and stearic acid, a fatty substance. It's used in tablets and capsules as a lubricant and glidant to help ingredients flow smoothly during manufacturing and prevent sticking.
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Propylene glycol is a clear liquid derived from petroleum or vegetable sources. It acts as a solvent, humectant, and preservative in medicines, helping dissolve active ingredients and maintain product stability.
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UNII 46N107B71O
Shellac is a natural resin secreted by the lac beetle. It's used as a coating on tablets and capsules to control how quickly the medicine dissolves and to improve appearance and stability.
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Silicon dioxide is a naturally occurring mineral used as a glidant and anti-caking agent. It helps powder ingredients flow smoothly and prevents clumping during manufacturing and storage.
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UNII 15FIX9V2JP
Titanium dioxide is a bright white mineral powder commonly used as a colorant and opacifying agent. It makes pills and tablets white or lighter in color and helps make coatings non-transparent.
15 inactive ingredients listed in the exact product block matched to this NDC.
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ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.Inactive ingredient FAQ
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💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per ea | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | $0.187 | $18.68 / 100 capsule |
| Medicaid paysCMS SDUD · 12 mo | $1.18 | $117.82 / 100 capsule |
| Medicare drug plans payPart D · Q2 2026 | $0.3254 | $32.54 / 100 capsule |
| Medicare Part B allowsASP · J8999 | No ASP payment limit on file for J8999 this quarter. | |
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🧾 Billing & reimbursement
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🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Hydroxyurea 500 mg 00555-0882-02 | Teva | 100 capsules | $0.187 | — | Availability likely | — |
| Hydroxyurea 500 mgthis 00904-6939-61 | Major | 100 capsules | $0.187 | AB | Availability likely | — |
| Hydroxyurea 500 mg 49884-0724-01 | Par | 100 capsules | $0.187 | AB | Availability likely | — |
| Hydroxyurea 500 mg 68084-0284-01 | American | 100 capsules | $0.187 | AB | Availability likely | — |
| Hydroxyurea 500 mg 69315-0164-01 | Leading | 100 capsules | $0.187 | AB | Availability likely | — |
| Hydroxyurea 500 mg 70069-0820-01 | Somerset | 100 capsules | $0.187 | AB | Availability likely | — |
| Hydroxyurea 500 mg 42291-0321-01 | AvKARE | 100 capsules | — | — | FDA listed | — |
| Hydroxyurea 500 mg 51407-0909-01 | Golden | 100 capsules | — | AB | FDA listed | — |
| Hydrea 500 mg 61269-0835-10 | H2-Pharma | 100 capsules | — | AB | FDA listed | — |
| Hydroxyurea 500 mg 67046-1619-03 | Coupler | 30 capsules | — | AB | FDA listed | — |
| Hydroxyurea 500 mg 67184-0607-01 | Qilu | 100 capsules | — | AB | FDA listed | — |
| Hydrea 500 mg 80725-0810-10 | Waylis | 100 capsules | — | AB | FDA listed | — |
Where does this data come from?
⏳ Availability & generic status
This product is an FDA-approved generic. Other versions of the same drug are listed under Therapeutic equivalents, least expensive first.
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🗺️ Medicaid utilization & spend
📊 Medicare Part D spend CMS · PART D · 2026 (Q1)
🔬 Reported adverse events (FAERS)
Top reported reactions
Age at onset
Reporter sex
Serious outcomes
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📦 Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Status |
|---|---|---|---|
| 00904-6939-61 You're viewing this | 100 BLISTER PACK in 1 CARTON (0904-6939-61) / 1 CAPSULE in 1 BLISTER PACK | 1999-02-24 | Active |
📄 Full prescribing information FDA SPL
🎯 Indications and Usage ▾
1 INDICATIONS AND USAGE Hydroxyurea capsules are indicated for the treatment of: • Resistant chronic myeloid leukemia. • Locally advanced squamous cell carcinomas of the head and neck (excluding the lip) in combination with chemoradiation. Hydroxyurea capsules are an antimetabolite indicated for the treatment of: • Resistant chronic myeloid leukemia. ( 1) • Locally advanced squamous cell carcinomas of the head and neck, (excluding lip) in combination with concurrent chemoradiation.
( 1 )
⏱️ Dosage and Administration ▾
2 DOSAGE AND ADMINISTRATION Individualize treatment based on tumor type, disease state, response to treatment, patient risk factors, and current clinical practice standards. (2.1) Renal impairment: Reduce the dose of hydroxyurea capsules by 50% in patients with creatinine clearance less than 60 mL/min. (2.3, 8.6, 12.3)
2.1Dosing Information Hydroxyurea capsules are used alone or in conjunction with other antitumor agents or radiation therapy to treat neoplastic diseases. Individualize treatment based on tumor type, disease state, response to treatment, patient risk factors, and current clinical practice standards. Base all dosage on the patient’s actual or ideal weight, whichever is less.
Hydroxyurea capsules are a cytotoxic drug. Follow applicable special handling and disposal procedures [see References (15) ] . Swallow hydroxyurea capsules whole.
Do NOT open, break, or chew capsules because hydroxyurea capsules are a cytotoxic drug. Prophylactic administration of folic acid is recommended [see Warnings and Precautions (5.8) ] . Monitor blood counts at least once a week during hydroxyurea capsules therapy.
Severe anemia must be corrected before initiating therapy with hydroxyurea capsules.
2.2Dose Modifications for Toxicity Monitor for the following and reduce the dose or discontinue hydroxyurea capsules accordingly: • Myelosuppression [ see Warnings and Precautions (5.1) ]. • Cutaneous vasculitis [ see Warnings and Precautions (5.5) ] Consider dose modifications for other toxicities.
2.3Dose Modifications for Renal Impairment Reduce the dose of hydroxyurea capsules by 50% in patients with measured 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 (mL/min) Recommended Hydroxyurea Capsules Initial Dose (mg/kg once daily) ≥60 15 <60 or ESRD* 7.5 *On dialysis days, administer hydroxyurea capsules to patients following hemodialysis. Close monitoring of hematologic parameters is advised in these patients.
💊 Dosage Forms and Strengths ▾
3 DOSAGE FORMS AND STRENGTHS Capsules: 500 mg dark green opaque (cap) printed “724” in white ink/ pink opaque (body) printed “par” in black ink. • Capsules: 500 mg (3)
⛔ Contraindications ▾
4 CONTRAINDICATIONS Hydroxyurea capsules are contraindicated in patients who have demonstrated a previous hypersensitivity to hydroxyurea or any other component of the formulation. • In patients who have demonstrated a previous hypersensitivity to hydroxyurea or any other component of its formulation. ( 4 )
⚠️ Warnings and Cautions ▾
5 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 capsules. ( 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 capsules 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 )
5.1Myelosuppression 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.
5.2Hemolytic 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.
5.3Malignancies 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.
5.4Embryo-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 )].
5.5Vasculitic 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 hist…
🤒 Adverse Reactions ▾
6 ADVERSE REACTIONS The following clinically significant adverse reactions are described in detail in other labeling sections: • Myelosuppression [see Warnings and Precautions ( 5.1 )] • Hemolytic anemia [see Warnings and Precautions ( 5.2 )] • Malignancies [see Warnings and Precautions ( 5.3 )] • Vasculitic toxicities [see Warnings and Precautions ( 5.5 )] • Risks with concomitant use of antiretroviral drugs [see Warnings and Precautions ( 5.7 )] • Radiation recall [see Warnings and Precautions ( 5.8 )] • Macrocytosis [see Warnings and Precautions ( 5.9 )] • Pulmonary Toxicity [see Warnings and Precautions ( 5.
10 )] Most common adverse reactions (≥30%) are hematological, gastrointestinal symptoms, and anorexia. (6) To report SUSPECTED ADVERSE REACTIONS, contact Par Health at 1-800-828-9393 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
6.1Postmarketing Experience The following adverse reactions have been identified during post-approval use of hydroxyurea capsules. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency. • Reproductive System and Breast disorders: azoospermia, and oligospermia • Gastrointestinal disorders: stomatitis, nausea, vomiting, diarrhea, and constipation • Metabolism and Nutrition disorders: anorexia, tumor lysis syndrome • Skin and subcutaneous tissue disorders: maculopapular rash, skin ulceration, cutaneous lupus erythematosus, dermatomyositis-like skin changes, peripheral and facial erythema, hyperpigmentation, nail hyperpigmentation, atrophy of skin and nails, scaling, violet papules, and alopecia • Renal and urinary disorders: dysuria, elevations in serum uric acid, blood urea nitrogen (BUN), and creatinine levels • Nervous system disorders: headache, dizziness, drowsiness, disorientation, hallucinations, and convulsions • General Disorders: fever, chills, malaise, edema, and asthenia • Hepatobiliary disorders: elevation of hepatic enzymes, cholestasis, and hepatitis • Respiratory disorders: diffuse pulmonary infiltrates, dyspnea, and pulmonary fibrosis, interstitial lung disease, pneumonitis, alveolitis, allergic alveolitis and cough • Immune disorders: systemic lupus erythematosus • Hypersensitivity: Drug-induced fever (pyrexia) (>39°C, >102°F) requiring hospitalization has been reported concurrently with gastrointestinal, pulmonary, musculoskeletal, hepatobiliary, dermatological or cardiovascular manifestations.
Onset typically occurred within 6 weeks of initiation and resolved upon discontinuation of hydroxyurea. Upon re-administration fever re-occurred typically within 24 hours. • Blood and lymphatic system disorders: hemolytic anemia Adverse reactions observed with combined hydroxyurea and irradiation therapy are similar to those reported with the use of hydroxyurea or radiation treatment alone. These effects primarily include bone marrow depression (anemia and leukopenia), gastric irritation, and mucositis.
Almost all patients receiving an adequate course of combined hydroxyurea and irradiation therapy will demonstrate concurrent leukopenia. Platelet depression (<100,000 cells/mm 3 ) has occurred in the presence of marked leukopenia. Hydroxyurea capsules may potentiate some adverse reactions usually seen with irradiation alone, such as gastric distress and mucositis.
🔄 Drug Interactions ▾
7 DRUG INTERACTIONS • Antiretroviral drugs (7.1) • Laboratory Test Interference. ( 7.2 )
7.1Increased Toxicity with Concomitant Use of Antiretroviral Drugs Pancreatitis In patients with HIV infection during therapy with hydroxyurea and didanosine, with or without stavudine, fatal and nonfatal pancreatitis have occurred. Hydroxyurea is not indicated for the treatment of HIV infection; however, if patients with HIV infection are treated with hydroxyurea, and in particular, in combination with didanosine and/or stavudine, close monitoring for signs and symptoms of pancreatitis is recommended. Permanently discontinue therapy with hydroxyurea in patients who develop signs and symptoms of pancreatitis.
Hepatotoxicity Hepatotoxicity and hepatic failure resulting in death have been reported during postmarketing surveillance in patients with HIV infection treated with hydroxyurea and other antiretroviral drugs. Fatal hepatic events were reported most often in patients treated with the combination of hydroxyurea, didanosine, and stavudine. Avoid this combination.
Peripheral Neuropathy Peripheral neuropathy, which was severe in some cases, has been reported in patients with HIV infection receiving hydroxyurea in combination with antiretroviral drugs, including didanosine, with or without stavudine.
7.2Laboratory Test Interference Interference with Uric Acid, Urea, or Lactic Acid Assays Studies have shown that there is an analytical interference of hydroxyurea with the enzymes (urease, uricase, and lactate dehydrogenase) used in the determination of urea, uric acid, and lactic acid, rendering falsely elevated results of these in patients treated with hydroxyurea. Interference with Continuous Glucose Monitoring Systems 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.
👥 Use in Specific Populations ▾
8 USE IN SPECIFIC POPULATIONS • Lactation: Advise women not to breastfeed . ( 8.2 ) • Geriatric Use: Care should be taken in dose selection and may require a lower dose regimen and monitoring of renal function. (8.5)
8.1Pregnancy Risk Summary Hydroxyurea capsules can cause fetal harm based on findings from animal studies and the drug’s mechanism of action [see Clinical Pharmacology (12.1) ]. There are no data with hydroxyurea capsules use in pregnant women to inform a drug-associated risk. In animal reproduction studies, administration of hydroxyurea to pregnant rats and rabbits during organogenesis produced embryotoxic and teratogenic effects at doses 0.8 times and 0.3 times, respectively, the maximum recommended human daily dose on a mg/m 2 basis ( see Data ).
Advise women of the potential risk to a fetus and to avoid becoming pregnant while being treated with hydroxyurea capsules. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal Data Hydroxyurea has been demonstrated to be a potent teratogen in a wide variety of animal models, including mice, hamsters, cats, miniature swine, dogs, and monkeys at doses within 1-fold of the human dose given on a mg/m 2 basis.
Hydroxyurea is embryotoxic and causes fetal malformations (partially ossified cranial bones, absence of eye sockets, hydrocephaly, bipartite sternebrae, missing lumbar vertebrae) at 180 mg/kg/day (about 0.8 times the maximum recommended human daily dose on a mg/m 2 basis) in rats and at 30 mg/kg/day (about 0.3 times the maximum recommended human daily dose on a mg/m 2 basis) in rabbits. Embryotoxicity was characterized by decreased fetal viability, reduced live litter sizes, and developmental delays. Hydroxyurea crosses the placenta.
Single doses of ≥375 mg/kg (about 1.7 times the maximum recommended human daily dose on a mg/m 2 basis) to rats caused growth retardation and impaired learning ability.
8.2Lactation Risk Summary Hydroxyurea is excreted in human milk. Because of the potential for serious adverse reactions in a breastfed infant from hydroxyurea, including carcinogenicity, discontinue breastfeeding during treatment with hydroxyurea capsules.
8.3Females and Males of Reproductive Potential Pregnancy Testing Verify the pregnancy status of females of reproductive potential prior to initiating hydroxyurea capsules therapy. Contraception Females Hydroxyurea capsules can cause fetal harm when administered to a pregnant woman [ 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 females to immediately report pregnancy. Males Hydroxyurea capsules may damage spermatozoa and testicular tissue, resulting in possible genetic abnormalities. Males with female sexual partners of reproductive potential should use effective contraception during and after treatment with hydroxyurea capsules for at least 1 year after therapy [ see Nonclinical Toxicology (13.1) ].
Infertility Males Based on findings in animals and humans, male fertility may be compromised by treatment with hydroxyurea capsules. Azoospermia or oligospermia, sometimes reversible, has been observed in men. Inform male patients about the possibility of sperm conservation before the start of therapy [ see Adverse Reactions (6) and Nonclinical Toxicology (13.1) ] .
8.4Pediatric Use Safety and effectiveness in pediatric patients have not been established.
8.5Geriatric Use Elderly patients may be more sensitive to the effects of hydroxyurea and may require a lower dose regimen. Hydroxyurea is excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose se…
🤰 Pregnancy ▾
8.1Pregnancy Risk Summary Hydroxyurea capsules can cause fetal harm based on findings from animal studies and the drug’s mechanism of action [see Clinical Pharmacology (12.1) ]. There are no data with hydroxyurea capsules use in pregnant women to inform a drug-associated risk. In animal reproduction studies, administration of hydroxyurea to pregnant rats and rabbits during organogenesis produced embryotoxic and teratogenic effects at doses 0.8 times and 0.3 times, respectively, the maximum recommended human daily dose on a mg/m 2 basis ( see Data ).
Advise women of the potential risk to a fetus and to avoid becoming pregnant while being treated with hydroxyurea capsules. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal Data Hydroxyurea has been demonstrated to be a potent teratogen in a wide variety of animal models, including mice, hamsters, cats, miniature swine, dogs, and monkeys at doses within 1-fold of the human dose given on a mg/m 2 basis.
Hydroxyurea is embryotoxic and causes fetal malformations (partially ossified cranial bones, absence of eye sockets, hydrocephaly, bipartite sternebrae, missing lumbar vertebrae) at 180 mg/kg/day (about 0.8 times the maximum recommended human daily dose on a mg/m 2 basis) in rats and at 30 mg/kg/day (about 0.3 times the maximum recommended human daily dose on a mg/m 2 basis) in rabbits. Embryotoxicity was characterized by decreased fetal viability, reduced live litter sizes, and developmental delays. Hydroxyurea crosses the placenta.
Single doses of ≥375 mg/kg (about 1.7 times the maximum recommended human daily dose on a mg/m 2 basis) to rats caused growth retardation and impaired learning ability.
🧒 Pediatric Use ▾
8.4Pediatric Use Safety and effectiveness in pediatric patients have not been established.
🧓 Geriatric Use ▾
8.5Geriatric Use Elderly patients may be more sensitive to the effects of hydroxyurea and may require a lower dose regimen. Hydroxyurea is excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function [see Dosage and Administration (2.3) ] .
🆘 Overdosage ▾
10 OVERDOSAGE Acute mucocutaneous toxicity has been reported in patients receiving hydroxyurea at dosages several times the therapeutic dose. Soreness, violet erythema, edema on palms and soles followed by scaling of hands and feet, severe generalized hyperpigmentation of the skin, and stomatitis have also been observed.
🧬 Clinical Pharmacology ▾
12 CLINICAL PHARMACOLOGY
12.1Mechanism 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.
12.3Pharmacokinetics 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 to <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) ] .
🧬 Mechanism of Action ▾
12.1Mechanism 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.
📦 How Supplied / Storage and Handling ▾
16 HOW SUPPLIED/STORAGE AND HANDLING
16.1How Supplied Hydroxyurea capsules, USP 500 mg are dark green opaque (cap) printed "724" in white ink/ pink opaque (body) printed "par" in black ink capsules. Cartons of 100 capsules (10 capsules each blister pack x 10), NDC 0904-6939-61 WARNING: This Unit Dose package is not child resistant and is Intended for Institutional Use Only. Keep this and all drugs out of the reach of children. Dispense in a tight container as defined in the USP.
16.2Storage Store at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature]. Keep tightly closed.
16.3Handling and Disposal Hydroxyurea capsules are a cytotoxic drug. Follow applicable special handling and disposal procedures [see References (15) ] . To decrease the risk of contact, advise caregivers to wear disposable gloves when handling hydroxyurea capsules or bottles containing hydroxyurea capsules.
Wash hands with soap and water before and after contact with the bottle or capsules when handling hydroxyurea capsules. Do not open hydroxyurea capsules. Avoid exposure to crushed or opened capsules.
If contact with crushed or opened capsules occurs on the skin, wash affected area immediately and thoroughly with soap and water. If contact with crushed or opened capsules occurs on the eye(s), the affected area should be flushed thoroughly with water or isotonic eyewash designated for that purpose for at least 15 minutes. If the powder from the capsule is spilled, immediately wipe it up with a damp disposable towel and discard in a closed container, such as a plastic bag; as should the empty capsules.
The spill areas should then be cleaned three times using a detergent solution followed by clean water. Keep the medication away from children and pets. Contact your doctor for instructions on how to dispose of outdated capsules.
📋 Description ▾
11 DESCRIPTION Hydroxyurea Capsules, USP are an antimetabolite available for oral use as capsules containing 500 mg hydroxyurea. Inactive ingredients include colloidal silicon dioxide, magnesium stearate, colorants (D&C Yellow No. 10, FD&C Blue No.
1 and FD&C Red No. 40), gelatin, and titanium dioxide. Imprinting ink constituents: D&C Yellow No.
10 Aluminum Lake, FD&C Blue No. 1 Aluminum Lake, FD&C Blue No. 2 Aluminum Lake, FD&C Red No.
40 Aluminum Lake, shellac glaze, propylene glycol, ammonium hydroxide, simethicone, synthetic black iron oxide and titanium dioxide. Hydroxyurea is a white to off-white crystalline powder. It is hygroscopic and freely soluble in water, but practically insoluble in alcohol.
The empirical formula is CH 4 N 2 O 2 and it has a molecular weight of 76.05. Its structural formula is: This is the structure
💬 Information for Patients ▾
17 PATIENT COUNSELING INFORMATION • There is a risk of myelosuppression. Monitoring blood counts weekly throughout the duration of therapy should be emphasized to patients taking hydroxyurea capsules. Advise patients to report signs and symptoms of infection or bleeding immediately [see Warnings and Precautions ( 5.1 )]. • Advise patients of the risk of hemolytic anemia.
Advise patients that they will have blood tests to evaluate for this if they develop persistent anemia [ see Warnings and Precautions ( 5.2 )]. • Advise patients that there is a risk of cutaneous vasculitic toxicities and secondary malignancies including leukemia and skin cancers [see Warnings and Precautions ( 5.3 , 5.5 )]. • Advise females of reproductive potential of the potential risk to a fetus and to inform their healthcare provider of a known or suspected pregnancy. Advise females and males of reproductive potential to use contraception during and after treatment with hydroxyurea capsules [see Warnings and Precautions ( 5.4 ) and Use in Specific Populations ( 8.1 , 8.3 )]. • Advise patients to inform their healthcare provider if they have received or are planning to receive vaccinations while taking hydroxyurea capsules as this may result in a severe infection [see Warnings and Precautions ( 5.6 )]. • Advise females to discontinue breastfeeding during treatment with hydroxyurea capsules [see Use in Specific Populations ( 8.2 )]. • Patients with HIV infection should contact their physician for signs and symptoms of pancreatitis, hepatic events, and peripheral neuropathy [see Warnings and Precautions ( 5.7 )]. • Post-irradiation erythema can occur in patients who have received previous irradiation therapy [see Warnings and Precautions ( 5.8 )]. • Advise patients of the symptoms of potential pulmonary toxicity and instruct them to seek prompt medical attention in the event of pyrexia, cough, dyspnea, or other respiratory symptoms [see Warnings and Precautions ( 5.10 )] . • Advise patients to notify their healthcare provider if they are using a continuous glucose monitoring system while taking hydroxyurea capsules [see Warnings and Precautions ( 5.11 )].
For more information, go to www.parhealth.com or call 1-800-828-9393. Manufactured for: Par Health USA Rochester, MI 48307 U.S.A. Made in India Packaged and Distributed by: MAJOR® PHARMACEUTICALS Indianapolis, IN 46268 USA Refer to package label for Distributor's NDC Number Neutral Code: TN/DRUGS/TN00002121 © 2026 Par Health, Inc. or one of its affiliates.
Revised: 04/2026