Zidovudine

1 INDICATIONS AND USAGE Zidovudine capsules are a nucleoside analogue reverse transcriptase inhibitor indicated for: Treatment of Human Immunodeficiency Virus (HIV-1) infection in combination with other antiretroviral agents. (1.1) Prevention of maternal-fetal HIV-1 transmission. (1.2) 1.1 Treatment of HIV-1 Zidovudine capsules, a nucleoside reverse transcriptase inhibitor, are indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection. 1.2 Prevention of Maternal-Fetal HIV-1 Transmission Zidovudine capsules are indicated for the prevention of maternal-fetal HIV-1 transmission [see Dosage and Administration (2.3) ]. The indication is based on a dosing regimen that included 3 components: antepartum therapy of HIV-1-infected mothers intrapartum therapy of HIV-1-infected mothers post-partum therapy of HIV-1-exposed neonate Points to consider prior to initiating zidovudine capsules in pregnant women for the prevention of maternal-fetal HIV-1 transmission include: In most cases, zidovudine capsules for prevention of maternal-fetal HIV-1 transmission should be given in combination with other antiretroviral drugs. Prevention of HIV-1 transmission in women who have received zidovudine capsules for a prolonged period before pregnancy has not been evaluated. Because the fetus is most susceptible to the potential teratogenic effects of drugs during the first 10 weeks of gestation and the risks of therapy with zidovudine capsules during that period are not fully known, women in the first trimester of pregnancy who do not require immediate initiation of antiretroviral therapy for their own health may consider delaying use; this indication is based on use after 14 weeks' gestation.

2 DOSAGE AND ADMINISTRATION Treatment of HIV-1 infection: Adults: Recommended oral dosage is 300 mg twice a day with other antiretroviral agents. (2.1) Pediatric patients (aged 4 weeks to less than 18 years): Dosage should be calculated based on body weight not to exceed adult dose. (2.2) Prevention of maternal-fetal HIV-1 transmission: Specific dosage instructions for mother and infant. (2.3) Patients with severe anemia and/or neutropenia: Dosage interruption may be necessary. ( 2.4 ) Renal impairment: Recommended oral dosage in hemodialysis or peritoneal dialysis or in patients with creatinine clearance (CrCl) less than 15 mL per minute is 100 mg every 6 to 8 hours. (2.5) 2.1 Adults - Treatment of HIV-1 Infection Oral Dosing The recommended oral dose of zidovudine capsules is 300 mg twice daily in combination with other antiretroviral agents. 2.2 Pediatric Patients (Aged 4 Weeks to Less than 18 Years) Healthcare professionals should pay special attention to accurate calculation of the dose of zidovudine capsules, transcription of the medication order, dispensing information, and dosing instructions to minimize risk for medication dosing errors. Prescribers should calculate the appropriate dose of zidovudine capsules for each child based on body weight (kg) and should not exceed the recommended adult dose. Before prescribing zidovudine capsules, children should be assessed for the ability to swallow capsules. If a child is unable to reliably swallow a zidovudine capsule, the zidovudine oral solution formulation should be prescribed. The recommended oral dosage in pediatric patients aged 4 weeks to less than 18 years and weighing greater than or equal to 4 kg is provided in Table 1. Zidovudine oral solution should be used to provide accurate dosage when capsules are not appropriate. Table 1. Recommended Pediatric Oral Dosage of Zidovudine Capsules Body Weight (kg) Total Daily Dose Dosage Regimen and Dose Twice Daily Three Times Daily 4 to <9 24 mg/kg/day 12 mg/kg 8 mg/kg ≥9 to <30 18 mg/kg/day 9 mg/kg 6 mg/kg ≥30 600 mg/day 300 mg 200 mg Alternatively, dosing for zidovudine capsules can be based on body surface area (BSA) for each child. The recommended oral dose of zidovudine capsules is 480 mg per m 2 per day in divided doses (240 mg per m 2 twice daily or 160 mg per m 2 three times daily). In some cases the dose calculated by mg per kg will not be the same as that calculated by BSA. 2.3 Prevention of Maternal-Fetal HIV-1 Transmission The recommended dosage regimen for administration to pregnant women (greater than 14 weeks of pregnancy) and their neonates is: Maternal Dosing 100 mg orally 5 times per day until the start of labor [see Clinical Studies (14.3) ] . During labor and delivery, intravenous zidovudine should be administered at 2 mg per kg (total body weight) over 1 hour followed by a continuous intravenous infusion of 1 mg per kg per hour (total body weight) until clamping of the umbilical cord. Neonatal Dosing Start neonatal dosing within 12 hours after birth and continue through 6 weeks of age. Neonates unable to receive oral dosing may be administered zidovudine intravenously. See Table 2 for dosing recommendations. Table 2. Recommended Neonatal Dosages of Zidovudine Route Total Daily Dose Dose and Dosage Regimen Oral 8 mg/kg/day 2 mg/kg every 6 hours Intravenous 6 mg/kg/day 1.5 mg/kg infused over 30 minutes, every 6 hours Use an appropriate-sized syringe with 0.1 mL graduation to ensure accurate dosing of the oral solution formulation in neonates. 2.4 Patients with Severe Anemia and/or Neutropenia Significant anemia (hemoglobin less than 7.5 g per dL or reduction greater than 25% of baseline) and/or significant neutropenia (granulocyte count less than 750 cells per mm 3 or reduction greater than 50% from baseline) may require a dose interruption until evidence of marrow recovery is observed [see Warnings and Precautions (5.1) ] . In patients who develop significant anemia, dose interruption does not necessarily …

3 DOSAGE FORMS AND STRENGTHS Zidovudine Capsules USP, 100 mg are white/white size ‘3’ hard gelatin capsules imprinted with ‘D’ on white cap and ‘01’ on white body with black edible ink. Capsules: 100 mg ( 3 )

4 CONTRAINDICATIONS Zidovudine capsules are contraindicated in patients who have had a potentially life-threatening hypersensitivity reaction (e.g., anaphylaxis, Stevens-Johnson syndrome) to any of the components of the formulations. Hypersensitivity to zidovudine or any of the components (e.g., anaphylaxis, Stevens-Johnson syndrome). (4)

6 ADVERSE REACTIONS The following adverse reactions are discussed in greater detail in other sections of the labeling: Hematologic toxicity, including neutropenia and anemia [see Boxed Warning , Warnings and Precautions (5.1) ]. Symptomatic myopathy [see Boxed Warning , Warnings and Precautions (5.2) ]. Lactic acidosis and severe hepatomegaly with steatosis [see Boxed Warning , Warnings and Precautions (5.3) ]. Hepatic decompensation in patients co-infected with HIV-1 and hepatitis C [see Warnings and Precautions (5.4) ]. Most commonly reported adverse reactions (incidence greater than or equal to 15%) in adult HIV-1 clinical trials were headache, malaise, nausea, anorexia, and vomiting. (6.1) Most commonly reported adverse reactions (incidence greater than or equal to 15%) in pediatric HIV-1 clinical trials were fever and cough. (6.1) Most commonly reported adverse reactions in neonates (incidence greater than or equal to 15%) in the prevention of maternal-fetal transmission of HIV-1 clinical trial were anemia and neutropenia. (6.1) To report SUSPECTED ADVERSE REACTIONS, contact Aurobindo Pharma USA, Inc. at 1-866-850-2876 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice. Adults The frequency and severity of adverse reactions associated with the use of zidovudine are greater in patients with more advanced infection at the time of initiation of therapy. Table 3 summarizes adverse reactions reported at a statistically significant greater incidence for subjects receiving oral zidovudine in a monotherapy trial. Table 3. Percentage (%) of Subjects with Adverse Reactions (Greater than or Equal to 5% Frequency) in Asymptomatic HIV-1 Infection (ACTG 019) a Not statistically significant versus placebo. Adverse Reaction Zidovudine 500 mg/day (n = 453) Placebo (n = 428) Body as a whole Asthenia Headache Malaise Gastrointestinal Anorexia Constipation Nausea Vomiting 9% a 63% 53% 20% 6% a 51% 17% 6% 53% 45% 11% 4% 30% 10% In addition to the adverse reactions listed in Table 3, adverse reactions observed at an incidence of greater than or equal to 5% in any treatment arm in clinical trials (NUCA3001, NUCA3002, NUCB3001, and NUCB3002) were abdominal cramps, abdominal pain, arthralgia, chills, dyspepsia, fatigue, insomnia, musculoskeletal pain, myalgia, and neuropathy. Additionally, in these trials hyperbilirubinemia was reported at an incidence of less than or equal to 0.8%. Selected laboratory abnormalities observed during a clinical trial of monotherapy with oral zidovudine are shown in Table 4. Table 4. Frequencies of Selected (Grade 3/4) Laboratory Abnormalities in Subjects with Asymptomatic HIV-1 Infection (ACTG 019) ULN = Upper limit of normal. Test (Abnormal Level) Zidovudine 500 mg/day (n = 453) Placebo (n = 428) Anemia (Hgb 5 x ULN) AST (>5 x ULN) 1% 2% 0% 3% 1% 10 x ULN) AST (>10 x ULN) Lipase (>2.5 x ULN) Total amylase (>2.5 x ULN) 8% 4% 1% 1% 2% 3% 3% 3% 2% 3% 3% 4% 3% 3% Macrocytosis was reported in the majority of pediatric subjects receiving zidovudine 180 mg per m 2 every 6 hours in open-label trials. Additionally, adverse reactions reported at an incidence of less than 6% in these trials were congestive heart failure, decreased reflexes, ECG abnormality, edema, hematuria, left ventricular dilation, nervousness/irritability, and weight loss. Use for the Prevention of Maternal-Fetal Transmission of HIV-1 In a randomized, double-blind, placebo-controlled trial in HIV-1-infected women and their neonates conducted to determine the utility of zidovudine for the prevention of maternal-fetal HIV-1 transmission, zidovudine oral solution at 2 mg per kg was administered every 6 hours for 6 weeks to neonates beginning within 12 hours following …

7 DRUG INTERACTIONS Avoid use with stavudine. ( 7.1 ) Avoid use with doxorubicin. ( 7.2 ) Bone marrow suppressive/cytotoxic agents: May increase the hematologic toxicity of zidovudine. ( 7.3 ) 7.1 Antiretroviral Agents Stavudine Concomitant use of zidovudine with stavudine should be avoided since an antagonistic relationship has been demonstrated in vitro . Nucleoside Analogues Affecting DNA Replication Some nucleoside analogues affecting DNA replication, such as ribavirin, antagonize the in vitro antiviral activity of zidovudine against HIV-1; concomitant use of such drugs should be avoided. 7.2 Doxorubicin Concomitant use of zidovudine with doxorubicin should be avoided since an antagonistic relationship has been demonstrated in vitro . 7.3 Hematologic/Bone Marrow Suppressive/Cytotoxic Agents Coadministration of ganciclovir, interferon alfa, ribavirin, and other bone marrow suppressive or cytotoxic agents may increase the hematologic toxicity of zidovudine.

8 USE IN SPECIFIC POPULATIONS Lactation: Women infected with HIV should be instructed not to breastfeed due to potential for HIV transmission. ( 8.2 ) 8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to zidovudine during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263. Risk Summary Available data from the APR show no difference in the overall risk of birth defects for zidovudine compared with the background rate for birth defects of 2.7% in the Metropolitan Atlanta Congenital Defects Program (MACDP) reference population (see Data) . The APR uses the MACDP as the U.S. reference population for birth defects in the general population. The MACDP evaluates women and infants from a limited geographic area and does not include outcomes for births that occurred at less than 20 weeks' gestation. The rate of miscarriage is not reported in the APR. The estimated background rate of miscarriage in clinically recognized pregnancies in the U.S. general population is 15% to 20%. The background risk for major birth defects and miscarriage for the indicated population is unknown. Hyperlactatemia, which may be due to mitochondrial dysfunction, has been reported in infants with in utero exposure to zidovudine-containing products. These events were transient and asymptomatic in most cases. There have been few reports of developmental delay, seizures, and other neurological disease. However, a causal relationship between these events and exposure to zidovudine-containing products in utero or peri-partum has not been established (see Data) . In an animal reproduction study, administration of oral zidovudine to female rats prior to mating and throughout gestation resulted in embryotoxicity at doses that produced systemic exposure (AUC) approximately 33 times higher than exposure at the recommended clinical dose. However, no embryotoxicity was observed after oral administration of zidovudine to pregnant rats during organogenesis at doses that produced systemic exposure (AUC) approximately 117 times higher than exposures at the recommended clinical dose. Administration of oral zidovudine to pregnant rabbits during organogenesis resulted in embryotoxicity at doses that produced systemic exposure (AUC) approximately 108 times higher than exposure at the recommended clinical dose. However, no embryotoxicity was observed at doses that produced systemic exposure (AUC) approximately 23 times higher than exposures at the recommended clinical dose (see Data) . Data Human Data: Based on prospective reports to the APR of over 13,000 exposures to zidovudine during pregnancy resulting in live births (including over 4,000 exposed in the first trimester), there was no difference between the overall risk of birth defects for zidovudine compared with the background birth defect rate of 2.7% in a U.S. reference population of the MACDP. The prevalence of birth defects in live births was 3.2% (95% CI: 2.7% to 3.8%) following first trimester exposure to zidovudine-containing regimens and 2.8% (95% CI: 2.5% to 3.2%) following second/third trimester exposure to zidovudine-containing regimens. A randomized, double-blind, placebo-controlled trial was conducted in HIV-1-infected pregnant women to determine the utility of zidovudine for the prevention of maternal-fetal HIV-1-transmission [see Clinical Studies (14.3) ] . Zidovudine treatment during pregnancy reduced the rate of maternal-fetal HIV-1 transmission from 24.9% for infants born to placebo-treated mothers to 7.8% for infants born to mothers treated with zidovudine. There were no differences in pregnancy-related adverse events between the treatment groups. Of the 363 neonates that were evaluated, congenital abnormalities occurred with similar frequency between neonates born to mothers who received zidovudine and neonates born to mothers who receive …

12.1 Mechanism of Action Zidovudine is an antiretroviral agent [see Microbiology (12.4) ] .

11 DESCRIPTION Zidovudine (formerly called azidothymidine [AZT]), a pyrimidine nucleoside analogue active against HIV-1. The chemical name of zidovudine is 3'-azido-3'-deoxythymidine; it has the following structural formula: Zidovudine USP is a white to beige, odorless, crystalline solid with a molecular weight of 267.24 and a solubility of 20.1 mg per mL in water at 25°C. The molecular formula is C 10 H 13 N 5 O 4 . Zidovudine capsules, USP are for oral administration. Each capsule contains 100 mg of zidovudine USP and the inactive ingredients microcrystalline cellulose, pregelatinised starch (maize), sodium starch glycolate, magnesium stearate. The 100 mg empty hard gelatin capsule, printed with edible black ink, consists of black iron oxide, and shellac. The capsule consists of titanium dioxide, sodium lauryl sulfate, and gelatin. Chemical Structure

10 OVERDOSAGE Acute overdoses of zidovudine have been reported in pediatric patients and adults. These involved exposures up to 50 grams. No specific symptoms or signs have been identified following acute overdosage with zidovudine apart from those listed as adverse events such as fatigue, headache, vomiting, and occasional reports of hematological disturbances. Patients recovered without permanent sequelae. Hemodialysis and peritoneal dialysis appear to have a negligible effect on the removal of zidovudine while elimination of its primary metabolite, 3′-azido-3′-deoxy-5′- O -β- D -glucopyranuronosylthymidine (GZDV), is enhanced. If overdose occurs, the patient should be monitored for evidence of toxicity and given standard supportive treatment as required.

16 HOW SUPPLIED/STORAGE AND HANDLING Zidovudine Capsules USP, 100 mg are white/white size ‘3’ hard gelatin capsules imprinted with ‘D’ on white cap and ‘01’ on white body with black edible ink. Bottles of 100 NDC 65862-107-01 10 x 10 Unit-dose Capsules NDC 65862-107-10 Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature]. Protect from moisture.