FULL PRESCRIBING INFORMATION
Zidovudine, one of the 2 active ingredients in Lamivudine and Zidovudine Tablets, has been associated with hematologic toxicity including neutropenia and anemia, particularly in patientswith advanced HIV-1 disease[see Warnings and Precautions (5.1)].
Prolonged use of zidovudine has been associated with symptomatic myopathy [see Warnings and Precautions (5.2)].
Lactic acidosis and hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues alone or in combination, including lamivudine, zidovudine, and other antiretrovirals. Suspend treatment if clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity occur [see Warnings and Precautions (5.3)].
Acute exacerbations of hepatitis B have been reported in patients who are co-infected with hepatitis B virus (HBV) and HIV-1 and have discontinued lamivudine, which is one component of Lamivudine and Zidovudine Tablets. Hepatic function should be monitored closely with both clinical and laboratory follow-up for at least several months in patients who discontinue Lamivudine and Zidovudine Tablets and are co-infected with HIV-1 and HBV. If appropriate, initiation of anti-hepatitis B therapy may be warranted [see Warnings and Precautions (5.4)].
Indications and Usage for Lamivudine and Zidovudine Tablets
Lamivudine and Zidovudine Tablets, a combination of two nucleoside analogues, are indicated in combination with other antiretrovirals for the treatment of HIV-1 infection.
Lamivudine and Zidovudine Tablets Dosage and Administration
Adults and Adolescents Weighing ≥ 30 kg
The recommended oral dose of Lamivudine and Zidovudine Tablets USP 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) twice daily.
Pediatric Patients
The recommended oral dosage of scored Lamivudine and Zidovudine Tablets USP 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 twice daily.
Before prescribing Lamivudine and Zidovudine Tablets USP, children should be assessed for the ability to swallow tablets. If a child is unable to reliably swallow a lamivudine and zidovudine tablet USP, the liquid oral formulations should be prescribed: EPIVIR® (lamivudine) Oral Solution and RETROVIR® (zidovudine) Syrup.
Patients Requiring Dosage Adjustment
Because Lamivudine and Zidovudine Tablets USP are a fixed-dose combination tablet, they should not be prescribed for pediatric patients weighing less than 30 kg or patients requiring dosage adjustment, such as those with reduced renal function (creatinine clearance less than 50 mL/min), patients with hepatic impairment, or patients experiencing dose-limiting adverse reactions. Liquid and solid oral formulations of the individual components of Lamivudine and Zidovudine Tablets USP are available for these populations.
Dosage Forms and Strengths
Lamivudine and Zidovudine Tablets USP are white, scored, film-coated, convex, oval tablets, debossed on both tablet faces, such that when broken in half, the full "TVL2" code is present on both halves of the tablet ("TV" on one face and "L2" on the opposite face of the tablet).
Contraindications
Lamivudine and Zidovudine Tablets are contraindicated in patients with previously demonstrated clinically significant hypersensitivity (e.g., anaphylaxis, Stevens-Johnson syndrome) to any of the components of the product.
Warnings and Precautions
Hemotologic Toxicity/Bone Marrow Suppression
Zidovudine, a component of Lamivudine and Zidovudine Tablets, has been associated with hematologic toxicity including neutropenia and anemia, particularly in patients with advanced HIV-1 disease. Lamivudine and Zidovudine Tablets should be used with caution in patients who have bone marrow compromise evidenced by granulocyte count less than 1,000 cells/mm3 or hemoglobin less than 9.5 g/dL [see Adverse Reactions (6.1)].
Frequent blood counts are strongly recommended in patients with advanced HIV-1 disease who are treated with Lamivudine and Zidovudine Tablets. Periodic blood counts are recommended for other HIV-1-infected patients. If anemia or neutropenia develops, dosage interruption may be needed.
Myopathy
Myopathy and myositis, with pathological changes similar to that produced by HIV-1 disease, have been associated with prolonged use of zidovudine, and therefore may occur with therapy with Lamivudine and Zidovudine Tablets.
Lactic Acidosis/Hepatomegaly With Steatosis
Lactic acidosis and hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues alone or in combination, including lamivudine, zidovudine, and other antiretrovirals. A majority of these cases have been in women. Obesity and prolonged nucleoside exposure may be risk factors. Particular caution should be exercised when administering Lamivudine and Zidovudine Tablets to any patient with known risk factors for liver disease; however, cases have also been reported in patients with no known risk factors. Treatment with Lamivudine and Zidovudine Tablets should be suspended in any patient who develops clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity (which may include hepatomegaly and steatosis even in the absence of marked transaminase elevations).
Patients With HIV-1 and Hepatitis B Virus Co-Infection
Posttreatment Exacerbations of Hepatitis: In clinical trials in non-HIV-1-infected patients treated with lamivudine for chronic HBV, clinical and laboratory evidence of exacerbations of hepatitis have occurred after discontinuation of lamivudine. These exacerbations have been detected primarily by serum ALT elevations in addition to re-emergence of hepatitis B viral DNA (HBV DNA). Although most events appear to have been self-limited, fatalities have been reported in some cases. Similar events have been reported from postmarketing experience after changes from lamivudine-containing HIV-1 treatment regimens to non-lamivudine-containing regimens in patients infected with both HIV-1 and HBV. The causal relationship to discontinuation of lamivudine treatment is unknown. Patients should be closely monitored with both clinical and laboratory follow-up for at least several months after stopping treatment. There is insufficient evidence to determine whether re-initiation of lamivudine alters the course of posttreatment exacerbations of hepatitis.
Important Differences Among Lamivudine-Containing Products: Lamivudine and Zidovudine Tablets contain a higher dose of the same active ingredient (lamivudine) than EPIVIR-HBV® (lamivudine) Tablets and Oral Solution. EPIVIR-HBV® was developed for treating chronic hepatitis B. Safety and efficacy of lamivudine have not been established for treatment of chronic hepatitis B in patients co-infected with HIV-1 and HBV.
Emergence of Lamivudine-Resistant HBV: In non-HIV-infected patients treated with lamivudine for chronic hepatitis B, emergence of lamivudine-resistant HBV has been detected and has been associated with diminished treatment response (see full prescribing information for EPIVIR-HBV® for additional information). Emergence of hepatitis B virus variants associated with resistance to lamivudine has also been reported in HIV-1-infected patients who have received lamivudine-containing antiretroviral regimens in the presence of concurrent infection with hepatitis B virus.
Use With Other, Lamivudine-, Zidovudine-, and/or Emtricitabine-Containing Products
Lamivudine and Zidovudine Tablets are a fixed-dose combination of lamivudine and zidovudine. Lamivudine and Zidovudine Tablets should not be administered concomitantly with other lamivudine- or zidovudine-containing products including EPIVIR® (lamivudine) Tablets and Oral Solution, EPIVIR-HBV® Tablets and Oral Solution, RETROVIR® (zidovudine) Tablets, Capsules, Syrup, and IV Infusion, EPZICOM® (abacavir sulfate and lamivudine) Tablets, or TRIZIVIR® (abacavir sulfate, lamivudine, and zidovudine) Tablets; or emtricitabine-containing products, including ATRIPLA® (efavirenz, emtricitabine, and tenofovir), EMTRIVA® (emtricitabine), or TRUVADA® (emtricitabine and tenofovir).
Use With Interferon- and Ribavirin-Based Regimens
In vitro studies have shown ribavirin can reduce the phosphorylation of pyrimidine nucleoside analogues such as lamivudine and zidovudine. Although no evidence of a pharmacokinetic or pharmacodynamic interaction (e.g., loss of HIV-1/HCV virologic suppression) was seen when ribavirin was coadministered with lamivudine or zidovudine in HIV-1/HCV co-infected patients [see Clinical Pharmacology (12.3)], hepatic decompensation (some fatal) has occurred in HIV-1/HCV co-infected patients receiving combination antiretroviral therapy for HIV-1 and interferon alfa with or without ribavirin. Patients receiving interferon alfa with or without ribavirin and Lamivudine and Zidovudine Tablets should be closely monitored for treatment-associated toxicities, especially hepatic decompensation, neutropenia, and anemia. Discontinuation of Lamivudine and Zidovudine Tablets should be considered as medically appropriate. Dose reduction or discontinuation of interferon alfa, ribavirin, or both should also be considered if worsening clinical toxicities are observed, including hepatic decompensation (e.g., Child-Pugh greater than 6) (see the complete prescribing information for interferon and ribavirin).
Exacerbation of anemia has been reported in HIV-1/HCV co-infected patients receiving ribavirin and zidovudine. Coadministration of ribavirin and zidovudine is not advised.
Pancreatitis
Lamivudine and Zidovudine Tablets should be used with caution in patients with a history of pancreatitis or other significant risk factors for the development of pancreatitis. Treatment with Lamivudine and Zidovudine Tablets should be stopped immediately if clinical signs, symptoms, or laboratory abnormalities suggestive of pancreatitis occur [see Adverse Reactions (6.1)].
Immune Reconstitution Syndrome
Immune reconstitution syndrome has been reported in patients treated with combination antiretroviral therapy, including Lamivudine and Zidovudine Tablets. During the initial phase of combination antiretroviral treatment, patients whose immune systems respond may develop an inflammatory response to indolent or residual opportunistic infections (such as Mycobacterium avium infection, cytomegalovirus, Pneumocystis jirovecii pneumonia [PCP], or tuberculosis), which may necessitate further evaluation and treatment.
Fat Redistribution
Redistribution/accumulation of body fat including central obesity, dorsocervical fat enlargement (buffalo hump), peripheral wasting, facial wasting, breast enlargement, and “cushingoid appearance” have been observed in patients receiving antiretroviral therapy. The mechanism and long-term consequences of these events are currently unknown. A causal relationship has not been established.
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 hepatomegaly with steatosis [see Boxed Warning, Warnings and Precautions (5.3)].
- Acute 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 (5.6)].
- Exacerbation of anemia in HIV-1/HCV co-infected patients receiving ribavirin and zidovudine [see Warnings and Precautions (5.6)].
- Pancreatitis [see Warnings and Precautions (5.7)].
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 to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
Lamivudine Plus Zidovudine Administered As Separate Formulations: In 4 randomized, controlled trials of EPIVIR® (lamivudine) 300 mg per day plus RETROVIR® (zidovudine) 600 mg per day, the following selected adverse reactions and laboratory abnormalities were observed (see Tables 1 and 2).
| Adverse Reaction | EPIVIR® (Lamivudine) plus RETROVIR® (Zidovudine) (n = 251) |
| Body as a whole | |
| Headache | 35% |
| Malaise & fatigue | 27% |
| Fever or chills | 10% |
| Digestive | |
| Nausea | 33% |
| Diarrhea | 18% |
| Nausea & vomiting | 13% |
| Anorexia and/or decreased appetite | 10% |
| Abdominal pain | 9% |
| Abdominal cramps | 6% |
| Dyspepsia | 5% |
| Nervous system | |
| Neuropathy | 12% |
| Insomnia & other sleep disorders | 11% |
| Dizziness | 10% |
| Depressive disorders | 9% |
| Respiratory | |
| Nasal signs & symptoms | 20% |
| Cough | 18% |
| Skin | |
| Skin rashes | 9% |
| Musculoskeletal | |
| Musculoskeletal pain | 12% |
| Myalgia | 8% |
| Arthralgia | 5% |
Pancreatitis was observed in 9 of the 2,613 adult patients (0.3%) who received EPIVIR® (lamivudine) in controlled clinical trials [see Warnings and Precautions (5.7)].
Selected laboratory abnormalities observed during therapy are listed in Table 2.
| |
| Test (Abnormal Level) | EPIVIR® (Lamivudine) plus RETROVIR® (Zidovudine) % (n) |
| Neutropenia (ANC < 750/mm3) | 7.2% (237) |
| Anemia (Hgb < 8.0 g/dL) | 2.9% (241) |
| Thrombocytopenia (platelets < 50,000/mm3) | 0.4% (240) |
| ALT (> 5.0 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 patients assessed.
Postmarketing Experience
In addition to adverse reactions reported from clinical trials, the following reactions have been identified during post-approval use of EPIVIR® (lamivudine), RETROVIR® (zidovudine), and/or Lamivudine and Zidovudine Tablets. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to a combination of their seriousness, frequency of reporting, or potential causal connection to EPIVIR® (lamivudine), RETROVIR® (zidovudine), and/or Lamivudine and Zidovudine Tablets.
Body as a Whole: Redistribution/accumulation of body fat [see Warnings and Precautions (5.9)].
Cardiovascular: Cardiomyopathy.
Endocrine and Metabolic: Gynecomastia, hyperglycemia.
Gastrointestinal: Oral mucosal pigmentation, stomatitis.
General: Vasculitis, weakness.
Hemic and Lymphatic: Anemia, (including pure red cell aplasia and anemias progressing on therapy), lymphadenopathy, splenomegaly.
Hepatic and Pancreatic: Lactic acidosis and hepatic steatosis, pancreatitis, posttreatment exacerbation of hepatitis B [see Boxed Warning, Warnings and Precautions (5.3), (5.4), (5.7)].
Hypersensitivity: Sensitization reactions (including anaphylaxis), urticaria.
Musculoskeletal: Muscle weakness, CPK elevation, rhabdomyolysis.
Nervous: Paresthesia, peripheral neuropathy, seizures.
Respiratory: Abnormal breath sounds/wheezing.
Skin: Alopecia, erythema multiforme, Stevens-Johnson syndrome.
Drug Interactions
No drug interaction studies have been conducted using Lamivudine and Zidovudine Tablets [see Clinical Pharmacology (12.3)].
Antiretroviral Agents
Lamivudine: Zalcitabine: Lamivudine and zalcitabine may inhibit the intracellular phosphorylation of one another. Therefore, use of Lamivudine and Zidovudine Tablets in combination with zalcitabine is not recommended.
Zidovudine: Stavudine: Concomitant use of Lamivudine and Zidovudine Tablets with stavudine should be avoided since an antagonistic relationship with zidovudine has been demonstrated invitro.
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.
Doxorubicin
Zidovudine: Concomitant use of Lamivudine and Zidovudine Tablets with doxorubicin should be avoided since an antagonistic relationship with zidovudine has been demonstrated in vitro.
Hematologic/Bone Marrow Suppressive/Cytotoxic Agents
Zidovudine: Coadministration of ganciclovir, interferon alfa, ribavirin, and other bone marrow suppressive or cytotoxic agents may increase the hematologic toxicity of zidovudine.
Interferon- and Ribavirin-Based Regimens
Lamivudine: Although no evidence of a pharmacokinetic or pharmacodynamic interaction (e.g., loss of HIV-1/HCV virologic suppression) was seen when ribavirin was coadministered with lamivudine in HIV-1/HCV co-infected patients, hepatic decompensation (some fatal) has occurred in HIV-1/HCV co-infected patients receiving combination antiretroviral therapy for HIV-1 and interferon alfa with or without ribavirin [see Warnings and Precautions (5.5), Clinical Pharmacology (12.3)].
Trimethoprim/Sulfamethoxazole (TMP/SMX)
Lamivudine: No change in dose of either drug is recommended. There is no information regarding the effect on lamivudine pharmacokinetics of higher doses of TMP/SMX such as those used to treat PCP.
USE IN SPECIFIC POPULATIONS
Pregnancy
Teratogenic Effects
Pregnancy category C
Fetal Risk Summary: There are no adequate and well-controlled studies of lamivudine and zidovudine in pregnant women. Clinical trial data demonstrate that maternal zidovudine treatment during pregnancy reduces vertical transmission of HIV-1 infection to the fetus. Animal reproduction studies performed with lamivudine and zidovudine showed increased embryotoxicity and fetal malformations (zidovudine), and increased embryolethality (lamivudine). Lamivudine and Zidovudine Tablets should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Antiretroviral Pregnancy Registry: To monitor maternal-fetal outcomes of pregnant women exposed to lamivudine and zidovudine and other antiretroviral agents, an Antiretroviral Pregnancy Registry has been established. Physicians are encouraged to register patients by calling 1-800-258-4263.
Clinical Considerations: Treatment of HIV during pregnancy optimizes the health of both mother and fetus. Clinical trial data reviewed by FDA demonstrate that maternal zidovudine treatment significantly reduces vertical transmission of HIV-1 infection to the fetus [see Clinical Studies (14.2)]. Published data suggest that combination antiretroviral regimens may reduce the rate of vertical transmission even further.
Pharmacokinetics of lamivudine and zidovudine in pregnant women are similar to the pharmacokinetics in nonpregnant women. No dose adjustments are needed during pregnancy.
In a clinical trial, adverse events among HIV-1-infected women were not different among untreated women and women treated with zidovudine. It is not known whether risks of adverse events associated with lamivudine are altered in pregnant women compared with other HIV-1-infected patients (see Human data below).
Data: Human Data:Lamivudine: Lamivudine pharmacokinetics were studied in pregnant women during 2 clinical studies conducted in South Africa. The study 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 daily with zidovudine, and 10 women at 38 weeks gestation using lamivudine 300 mg twice daily without other antiretrovirals. Lamivudine pharmacokinetics in pregnant women were similar to those seen in nonpregnant adults and in postpartum women. Lamivudine concentrations were generally similar in maternal, neonatal, and umbilical cord serum samples.
Zidovudine: 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. 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. Congenital abnormalities occurred with similar frequency between neonates born to mothers who received zidovudine and neonates born to mothers who received placebo. The observed abnormalities included problems in embryogenesis (prior to 14 weeks) or were recognized on ultrasound before or immediately after initiation of study drug [see Clinical Studies (14.2)].
Zidovudine pharmacokinetics were studied in a Phase 1 study of 8 women during the last trimester of pregnancy. As pregnancy progressed, there was no evidence of drug accumulation. The pharmacokinetics of zidovudine were similar to that of nonpregnant adults. Consistent with passive transmission of the drug across the placenta, zidovudine concentrations in neonatal plasma at birth were essentially equal to those in maternal plasma at delivery.
Animal Data: Lamivudine: Animal reproduction studies performed at oral doses up to 130 and 60 times the adult dose in rats and rabbits, respectively, revealed no evidence of teratogenicity due to lamivudine. Increased early embryolethality occurred in rabbits at exposure levels similar to those in humans. However, there was no indication of this effect in rats at exposure levels up to 35 times those in humans. Based on animal studies, lamivudine crosses the placenta and is transferred to the fetus [see Nonclinical Toxicology (13.2)].
Zidovudine: Increased fetal resorptions occurred in pregnant rats and rabbits treated with doses of zidovudine that produced drug plasma concentrations 66 to 226 times (rats) and 12 to 87 times (rabbits) the mean steady-state peak human plasma concentration following a single 100 mg dose of zidovudine. There were no other reported developmental anomalies. In another developmental toxicity study, pregnant rats received zidovudine up to near-lethal doses that produced peak plasma concentrations 350 times peak human plasma concentrations (300 times the daily exposure [AUC] in humans given 600 mg/day zidovudine). This dose was associated with marked maternal toxicity and an increased incidence of fetal malformations. However, there were no signs of teratogenicity at doses up to one fifth the lethal dose [see Nonclinical Toxicology (13.2)].
Nursing Mothers
The Centers for Disease Control and Prevention recommend that HIV-1-infected mothers in the United States not breastfeed their infants to avoid risking postnatal transmission of HIV-1 infection. Because of both the potential for HIV-1 transmission and serious adverse reactions in nursing infants, mothers should be instructed not to breastfeed if they are receiving Lamivudine and Zidovudine Tablets.
Although no studies of lamivudine and zidovudine excretion in breast milk have been performed, lactation studies performed with lamivudine and zidovudine show that both drugs are excreted in human breast milk. Samples of breast milk obtained from 20 mothers receiving lamivudine monotherapy (300 mg twice daily) or combination therapy (150 mg lamivudine twice daily and 300 mg zidovudine twice daily) had measurable concentrations of lamivudine. In another study, after administration of a single dose of 200 mg zidovudine to 13 HIV-1-infected women, the mean concentration of zidovudine was similar in human milk and serum.
Pediatric Use
Lamivudine and Zidovudine Tablets should not be administered to pediatric patients weighing less than 30 kg, because they are a fixed-dose combination that cannot be adjusted for this patient population.
Geriatric Use
Clinical studies of lamivudine and zidovudine did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. Lamivudine and Zidovudine Tablets are not recommended for patients with impaired renal function (i.e., creatinine clearance less than 50 mL/min) because they are a fixed-dose combination that cannot be adjusted.
Renal Impairment
Reduction of the dosages of lamivudine and zidovudine is recommended for patients with impaired renal function. Patients with creatinine clearance less than 50 mL/min should not receive Lamivudine and Zidovudine Tablets because they are a fixed-dose combination that cannot be adjusted.
Hepatic Impairment
A reduction in the daily dose of zidovudine may be necessary in patients with mild to moderate impaired hepatic function or liver cirrhosis. Lamivudine and Zidovudine Tablets are not recommended for patients with impaired hepatic function because they are a fixed-dose combination that cannot be adjusted.
Overdosage
Lamivudine and Zidovudine Tablets: There is no known antidote for Lamivudine and Zidovudine Tablets.
Lamivudine: One case of an adult ingesting 6 grams of lamivudine was reported; there were no clinical signs or symptoms noted and hematologic tests remained normal. 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. The only consistent findings were nausea and vomiting. Other reported occurrences included headache, dizziness, drowsiness, lethargy, confusion, and 1 report of a grand mal seizure. Hematologic changes were transient. All patients recovered. 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-ß-D-glucopyranuronosylthymidine (GZDV), is enhanced.
Lamivudine and Zidovudine Tablets Description
Lamivudine and Zidovudine Tablets USP are combination tablets containing lamivudine and zidovudine. Lamivudine (EPIVIR®) and zidovudine (RETROVIR®, 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 hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polysorbate 80, sodium starch glycolate, and titanium dioxide.
Lamivudine:
The chemical name of lamivudine is (-)-1-[(2R,5S)-2-(hydroxymethyl)-1,3-oxathiolan-5-yl] cytosine. Lamivudine is the (-)enantiomer of a dideoxy analogue of cytidine. Lamivudine has also been referred to as (-)2′,3′-dideoxy, 3′-thiacytidine. It has the following structural formula:
C8H11N3O3S M.W. 229.26
Lamivudine is a white to off-white solid with a solubility of approximately 70 mg/mL in water at 20°C.
Zidovudine:
The chemical name of zidovudine is 3′-azido-3′-deoxy-thymidine. It has the following structural formula:
C10H13N5O4 M.W. 267.24
Zidovudine is a white to yellowish powder sparingly soluble in water and freely soluble in alcohol.
Lamivudine and Zidovudine Tablets - Clinical Pharmacology
Mechanism of Action
Lamivudine and Zidovudine Tablets are an antiviral agent [see Clinical Pharmacology (12.4)].
Pharmacokinetics
Pharmacokinetics in Adults: Lamivudine and Zidovudine Tablets: One lamivudine and zidovudine tablet was bioequivalent to 1 EPIVIR® (lamivudine) Tablet (150 mg) plus 1 RETROVIR® (zidovudine) Tablet (300 mg) following single-dose administration to fasting healthy subjects (n = 24).
Lamivudine: The pharmacokinetic properties of lamivudine in fasting patients are summarized in Table 3. Following oral administration, lamivudine is rapidly absorbed and extensively distributed. Binding to plasma protein is low. Approximately 70% of an intravenous dose of lamivudine is recovered as unchanged drug in the urine. Metabolism of lamivudine is a minor route of elimination. In humans, the only known metabolite is the trans-sulfoxide metabolite (approximately 5% of an oral dose after 12 hours).
Zidovudine: The pharmacokinetic properties of zidovudine in fasting patients are summarized in Table 3. Following oral administration, zidovudine is rapidly absorbed and extensively distributed. Binding to plasma protein is low. Zidovudine is eliminated primarily by hepatic metabolism. The major metabolite of zidovudine is GZDV. GZDV area under the curve (AUC) is about 3 fold greater than the zidovudine AUC. Urinary recovery of zidovudine and GZDV accounts for 14% and 74% of the dose following oral administration, respectively. A second metabolite, 3′-amino-3′-deoxythymidine (AMT), has been identified in plasma. The AMT AUC was one fifth of the zidovudine AUC.
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| Parameter | Lamivudine | Zidovudine | ||
| Oral bioavailability (%) | 86 ± 16 | n = 12 | 64 ± 10 | n = 5 |
| Apparent volume of distribution (L/kg) | 1.3 ± 0.4 | n = 20 | 1.6 ± 0.6 | n = 8 |
| Plasma protein binding (%) | < 36 | < 38 | ||
| CSF:plasma ratio† | 0.12 [0.04 to 0.47] | n = 38‡ | 0.60 [0.04 to 2.62] | n = 39§ |
| Systemic clearance (L/hr/kg) | 0.33 ± 0.06 | n = 20 | 1.6 ± 0.6 | n = 6 |
| Renal clearance (L/hr/kg) | 0.22 ± 0.06 | n = 20 | 0.34 ± 0.05 | n = 9 |
| Elimination half-life (hr)¶ | 5 to 7 | 0.5 to 3 | ||
Effect of Food on Absorption of Lamivudine and Zidovudine Tablets: Lamivudine and Zidovudine Tablets may be administered with or without food. The lamivudine and zidovudine AUC following administration of Lamivudine and Zidovudine Tablets with food was similar when compared to fasting healthy subjects (n = 24).
Special Populations:
Pregnancy: See Use in Specific Populations (8.1).
Lamivudine and Zidovudine Tablets: No data are available.
Zidovudine: Zidovudine pharmacokinetics has been studied in a Phase 1 study of 8 women during the last trimester of pregnancy. As pregnancy progressed, there was no evidence of drug accumulation. The pharmacokinetics of zidovudine was similar to that of nonpregnant adults. Consistent with passive transmission of the drug across the placenta, zidovudine concentrations in neonatal plasma at birth were essentially equal to those in maternal plasma at delivery. Although data are limited, methadone maintenance therapy in 5 pregnant women did not appear to alter zidovudine pharmacokinetics. In a nonpregnant adult population, a potential for interaction has been identified.
Nursing Mothers: See Use in Specific Populations (8.3).
Pediatric Patients: Lamivudine and Zidovudine Tablets should not be administered to pediatric patients weighing less than 30 kg.
Geriatric Patients: The pharmacokinetics of lamivudine and zidovudine have not been studied in patients over 65 years of age.
Gender: A pharmacokinetic study in healthy male (n = 12) and female (n = 12) subjects showed no gender differences in zidovudine AUC∞ or lamivudine AUC∞ normalized for body weight.
Race: Lamivudine: There are no significant racial differences in lamivudine pharmacokinetics.
Zidovudine: The pharmacokinetics of zidovudine with respect to race have not been determined.
Drug Interactions: See Drug Interactions (7).
No drug interaction studies have been conducted using Lamivudine and Zidovudine Tablets. However, Table 4 presents drug interaction information for the individual components of Lamivudine and Zidovudine Tablets.
Lamivudine Plus Zidovudine: No clinically significant alterations in lamivudine or zidovudine pharmacokinetics were observed in 12 asymptomatic HIV-1-infected adult patients given a single dose of zidovudine (200 mg) in combination with multiple doses of lamivudine (300 mg q 12 hr).
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| Note: ROUTINE DOSE MODIFICATION OF LAMIVUDINE AND ZIDOVUDINE IS NOT WARRANTED WITH COADMINISTRATION OF THE FOLLOWING DRUGS. | |||||
| Drugs That May Alter Lamivudine Blood Concentrations | |||||
| Coadministered Drug and Dose | Lamivudine Dose | n | Lamivudine Concentrations | Concentration of Coadministered Drug | |
| AUC | Variability | ||||
| Nelfinavir 750 mg q 8 hr x 7 to 10 days | single 150 mg | 11 | ↑AUC 10% | 95% CI: 1% to 20% | ↔ |
| Trimethoprim 160 mg/Sulfamethoxazole 800 mg daily x 5 days | single 300 mg | 14 | ↑AUC 43% | 90% CI: 32% to 55% | ↔ |
| Drugs That May Alter Zidovudine Blood Concentrations | |||||
| Coadministered Drug and Dose | Zidovudine Dose | n | Zidovudine Concentrations | Concentration of Coadministered Drug | |
| AUC | Variability | ||||
| Atovaquone 750 mg q 12 hr with food | 200 mg q 8 hr | 14 | ↑AUC 31% | Range 23% to 78%† | |
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