Lamivudine and Zidovudine

1 INDICATIONS & USAGE Lamivudine and zidovudine tablets, a combination of 2 nucleoside analogues, is indicated in combination with other antiretrovirals for the treatment of human immunodeficiency virus type 1 (HIV-1) infection. Lamivudine and zidovudine tablets, a combination of 2 nucleoside analogue reverse transcriptase inhibitors, is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection. ( 1 )

2 DOSAGE & ADMINISTRATION • Adults and Adolescents weighing greater than or equal to 30 kg: 1 tablet orally twice daily. ( 2.1 ) • Pediatrics weighing greater than or equal to 30 kg: 1 tablet orally twice daily. ( 2.2 ) • Because lamivudine and zidovudine tablet is a fixed-dose tablet and cannot be dose adjusted, lamivudine and zidovudine tablets are not recommended in patients requiring dosage adjustment or with hepatic impairment or experiencing dose-limiting adverse reactions. ( 2.3 , 4 ) 2.1 Recommended Dosage for Adults and Adolescents The recommended dosage of lamivudine and zidovudine tablets in HIV-1-infected adults and adolescents weighing greater than or equal to 30 kg is 1 tablet (containing 150 mg of lamivudine and 300 mg of zidovudine) taken orally twice daily. 2.2 Recommended Dosage for Pediatric Patients The recommended dosage of scored lamivudine and zidovudine tablets for pediatric patients who weigh greater than or equal to 30 kg and for whom a solid oral dosage form is appropriate is 1 tablet administered orally twice daily. Before prescribing lamivudine and zidovudine tablets, children should be assessed for the ability to swallow tablets. If a child is unable to reliably swallow a lamivudine and zidovudine tablet, the liquid oral formulations should be prescribed: EPIVIR (lamivudine) oral solution and RETROVIR (zidovudine) syrup. 2.3 Not Recommended Due to Lack of Dosage Adjustment Because lamivudine and zidovudine tablet is a fixed-dose tablet and cannot be dose adjusted, lamivudine and zidovudine tablets are not recommended for: • pediatric patients weighing less than 30 kg [see Use in Specific Populations ( 8.4 )]. • patients with creatinine clearance less than 50 mL per minute [see Use in Specific Populations ( 8.6 )]. • patients with hepatic impairment [see Use in Specific Populations ( 8.7 )]. • patients experiencing dose-limiting adverse reactions. Liquid and solid oral formulations of the individual components of lamivudine and zidovudine tablets are available for these populations.

3 DOSAGE FORMS & STRENGTHS Lamivudine and zidovudine tablets, USP contain 150 mg of lamivudine and 300 mg of zidovudine. The tablets are white coloured, biconvex, modified capsule shaped, film-coated tablet having score on one side and 'ML 6' debossed on the other side of the tablet. Tablets: Scored 150 mg lamivudine and 300 mg zidovudine ( 3 )

4 CONTRAINDICATIONS Lamivudine and zidovudine tablets are contraindicated in patients with a previous hypersensitivity reaction to lamivudine or zidovudine. Lamivudine and zidovudine tablets are contraindicated in patients with a previous hypersensitivity reaction to lamivudine or zidovudine.

6 ADVERSE REACTIONS The following adverse reactions are discussed 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 ) ]. • Exacerbations of hepatitis B [see Boxed Warning, Warnings and Precautions ( 5.4 ) ]. • Hepatic decompensation in patients co-infected with HIV-1 and hepatitis C [see Warnings and Precautions ( 5.5 ) ]. • Exacerbation of anemia in HIV-1/HCV co-infected patients receiving ribavirin and zidovudine [see Warnings and Precautions ( 5.5 ) ]. • Pancreatitis [see Warnings and Precautions ( 5.6 ) ]. • Immune reconstitution syndrome [see Warnings and Precautions ( 5.7 ) ]. • Lipoatrophy [see Warnings and Precautions ( 5.8 ) ]. Most commonly reported adverse reactions (incidence greater than or equal to 15%) in clinical trials of combination lamivudine and zidovudine were headache, nausea, malaise and fatigue, nasal signs and symptoms, diarrhea, and cough. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Macleods Pharma USA, Inc. at 1-888-943-3210 or 1-855-926-3384 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 clinical practice. Lamivudine plus Zidovudine Administered as Separate Formulations In 4 randomized, controlled trials of EPIVIR 300 mg per day plus RETROVIR 600 mg per day, the following selected adverse reactions and laboratory abnormalities were observed (Tables 1 and 2). Table 1. Selected Clinical Adverse Reactions (Greater than or Equal to 5% Frequency) in 4 Controlled Clinical Trials with EPIVIR 300 mg per day and RETROVIR 600 mg per day Adverse Reaction EPIVIR plus RETROVIR (n = 251) Body as a whole Headache 35% Malaise & fatigue 27% Fever or chills Digestive 10% Nausea 33% Diarrhea 18% Nausea & vomiting 13% Anorexia and/or decreased appetite 10% Abdominal pain 9% Abdominal cramps 6% Dyspepsia Nervous system 5% Neuropathy 12% Insomnia & other sleep disorders 11% Dizziness 10% Depressive disorders Respiratory 9% Nasal signs & symptoms 20% Cough Skin 18% Skin rashes Musculoskeletal 9% Musculoskeletal pain 12% Myalgia 8% Arthralgia 5% Pancreatitis was observed in 9 of the 2,613 adult subjects (0.3%) who received EPIVIR in controlled clinical trials [ see Warnings and Precautions ( 5.6 )]. Selected laboratory abnormalities observed during therapy are listed in Table 2. Table 2. Frequencies of Selected Laboratory Abnormalities among Adults in 4 Controlled Clinical Trials of EPIVIR 300 mg per day plus RETROVIR 600 mg per day a Test (Abnormal Level) EPIVIR plus RETROVIR % (n) Neutropenia (ANC5.0 x ULN) 3.7% (241) AST (>5.0 x ULN) 1.7% (241) Bilirubin (>2.5 x ULN) 0.8% (241) Amylase (>2.0 x ULN) 4.2% (72) ULN = Upper limit of normal. ANC = Absolute neutrophil count. n = Number of subjects assessed. a Frequencies of these laboratory abnormalities were higher in subjects with mild laboratory abnormalities at baseline. 6.2 Postmarketing Experience The following adverse reactions have been identified during postmarketing use. Because these reactions are reported voluntarily from a population of unknown size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Body as a Whole Redistribution/accumulation of body fat [see Warnings and Precautions ( 5.8 ) ]. Cardiovascular Cardiomyopathy. Endocrine and Metabolic Gynecomastia, hyperglycemia. Gastrointestinal Oral mucosal pigmentation, stomatitis. General Vasculitis, weakness. Hemic and Lymphatic Anemia, (including pure red cell aplasia a …

7 DRUG INTERACTIONS • Agents antagonistic with zidovudine: Concomitant use should be avoided. ( 7.1 ) • Hematologic/bone marrow suppressive/cytotoxic agents: May increase the hematologic toxicity of zidovudine. ( 7.1 ) • Sorbitol: Coadministration of lamivudine and sorbitol may decrease lamivudine concentrations; when possible, avoid chronic coadministration. ( 7.2 ) 7.1 Zidovudine Agents Antagonistic with Zidovudine Concomitant use of zidovudine with the following drugs should be avoided since an antagonistic relationship has been demonstrated in vitro: • Stavudine • Doxorubicine • Nucleoside analogues, e.g., ribavirin Hematologic/Bone Marrow Suppressive/Cytotoxic Agents Coadministration with the following drugs may increase the hematologic toxicity of zidovudine: • Ganciclovir • Interferon alfa • Ribavirin • Other bone marrow suppressive or cytotoxic agents 7.2 Lamivudine Sorbitol Coadministration of single doses of lamivudine and sorbitol resulted in a sorbitol dose-dependent reduction in lamivudine exposures. When possible, avoid use of sorbitol-containing medicines with lamivudine-containing medicines [see Clinical Pharmacology ( 12.3 ) ].

8 USE IN SPECIFIC POPULATIONS Lactation: Women infected with HIV should be instructed not to breastfeed due to the 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 lamivudine and zidovudine tablets 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 lamivudine or 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 animal reproduction studies, oral administration of lamivudine to pregnant rabbits during organogenesis resulted in embryolethality at systemic exposure (AUC) similar to the recommended clinical dose; however, no adverse development effects were observed with oral administration of lamivudine to pregnant rats during organogenesis at plasma concentrations (C max ) 35 times the recommended clinical dose. 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: Lamivudine : Based on prospective reports to the APR of over 11,000 exposures to lamivudine during pregnancy resulting in live births (including over 4,500 exposed in the first trimester), there was no difference between the overall risk of birth defects for lamivudine 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 3.1% (95% CI: 2.6% to 3.6%) following first trimester exposure to lamivudine-containing regimens and 2.8% (95% CI: 2.5% to 3.3%) following second/third trimester exposure to lamivudine-containing regimens. Lamivudine pharmacokinetics were studied in pregnant women during 2 clinical trials conducted in South Africa. The trial assessed pharmacokinetics in 16 women at 36 weeks' gestation using 150 mg lamivudine twice daily with zidovudine, 10 women at 38 weeks' gestation using 150 mg lamivudine twice …

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

11 DESCRIPTION Lamivudine and zidovudine tablets, USP are combination tablets containing lamivudine and zidovudine. Lamivudine and zidovudine (azidothymidine, AZT, or ZDV) are synthetic nucleoside analogues with activity against HIV-1. Lamivudine and zidovudine tablets, USP are for oral administration. Each film-coated tablet contains 150 mg of lamivudine, 300 mg of zidovudine, and the inactive ingredients colloidal silicon dioxide, hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polysorbate 80, sodium starch glycolate, and titanium dioxide. Lamivudine The chemical name of lamivudine is (2R,cis)-4-amino-1-(2-hydroxymethyl-1,3-oxathiolan-5-yl)-(1H)-pyrimidin-2-one. Lamivudine is the (-)enantiomer of a dideoxy analogue of cytidine. Lamivudine has also been referred to as (-)2 ́,3 ́-dideoxy,3 ́-thiacytidine. It has a molecular formula of C 8 H 11 N 3 O 3 S and a molecular weight of 229.3 g per mol. It has the following structural formula: Lamivudine is a white to off-white crystalline solid and is soluble in water. Zidovudine The chemical name of zidovudine is 3′-azido-3′-deoxythymidine. It has a molecular formula of C 10 H 13 N 5 O 4 and a molecular weight of 267.24 g per mol. It has the following structural formula: Zidovudine is a white to beige, odorless, crystalline solid with a solubility of 20.1 mg per mL in water at 25°C. Meets USP Dissolution Test 2. lami zido

10 OVERDOSAGE There is no known specific treatment for overdose with lamivudine and zidovudine tablets. If overdose occurs, the patient should be monitored and standard supportive treatment applied as required. Lamivudine Because a negligible amount of lamivudine was removed via (4-hour) hemodialysis, continuous ambulatory peritoneal dialysis, and automated peritoneal dialysis, it is not known if continuous hemodialysis would provide clinical benefit in a lamivudine overdose event. Zidovudine 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.

16 HOW SUPPLIED/STORAGE AND HANDLING Lamivudine and Zidovudine Tablets, USP containing 150 mg lamivudine and 300 mg zidovudine, are white, film-coated, modified capsule shaped tablets with score on one side and 'ML 6' debossed on the other side. They are available as follows: 60 Tablets/Bottle (NDC 33342-003-09) 60 (6x10) unit-dose tablets (NDC 33342-003-24) 120 (12x10) unit-dose tablets (NDC 33342-003-25) Store at 20o to 25oC (68o to 77oF); excursions permitted to 15o to 30oC (59o to 86oF) [see USP Controlled Room Temperature] Preserve in well-closed containers, protected from light.