Abacavir, Lamivudine and ZidovudineTablets

Name: Abacavir, Lamivudine and ZidovudineTablets

Abacavir, Lamivudine and ZidovudineTablets Dosage and Administration

Screening for HLA-B*5701 Allele prior to Starting Abacavir, Lamivudine and Zidovudine Tablets

Screen for the HLA-B*5701 allele prior to initiating therapy with abacavir, lamivudine and zidovudine tablets [see BOXED WARNING, WARNINGS AND PRECAUTIONS (5.1)].

Recommended Dosage for Adults and Pediatric Patients Weighing at Least 40 kg

The recommended dosage of abacavir, lamivudine and zidovudine tablet is one tablet taken orally twice daily with or without food.

Not Recommended Due to Lack of Dosage Adjustment

Because abacavir, lamivudine and zidovudine tablet is a fixed-dose tablet and cannot be dose adjusted, abacavir, lamivudine and zidovudine tablet is not recommended for:

  • pediatric patients who weigh less than 40 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 mild hepatic impairment. Abacavir, lamivudine and zidovudine tablet is contraindicated in patients with moderate or severe hepatic impairment [see CONTRAINDICATIONS (4), USE IN SPECIFIC POPULATIONS (8.7)] .

Use in specific populations

Pregnancy

Pregnancy Exposure Registry

There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to abacavir, 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 abacavir, 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.

In animal reproduction studies, oral administration of abacavir to pregnant rats during organogenesis resulted in fetal malformations and other embryonic and fetal toxicities at exposures 35 times the human exposure (AUC) at the recommended clinical daily dose. However, no adverse developmental effects were observed following oral administration of abacavir to pregnant rabbits during organogenesis, at exposures approximately 9 times the human exposure (AUC) at the recommended clinical dose. 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 (Cmax) 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:

Abacavir

Based on prospective reports to the APR of over 2,000 exposures to abacavir during pregnancy resulting in live births (including over 1,000 exposed in the first trimester), there was no difference between the overall risk of birth defects for abacavir compared with the background birth defect rate of 2.7% in a U.S. reference population of the MACDP. The prevalence of defects in live births was 2.9% (95% CI: 2.0% to 4.1%) following first trimester exposure to abacavir-containing regimens and 2.7% (95% CI: 1.9% to 3.7%) following second/third trimester exposure to abacavir-containing regimens.

Abacavir has been shown to cross the placenta and concentrations in neonatal plasma at birth were essentially equal to those in maternal plasma at delivery [see CLINICAL PHARMACOLOGY (12.3)].

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%, 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 trials 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. These trials were not designed or powered to provide efficacy information. Lamivudine concentrations were generally similar in maternal, neonatal, and umbilical cord serum samples. In a subset of subjects, amniotic fluid specimens were collected following natural rupture of membranes and confirmed that lamivudine crosses the placenta in humans. Based on limited data at delivery, median (range) amniotic fluid concentrations of lamivudine were 3.9 (1.2 to 12.8)–fold greater compared with paired maternal serum concentration (n = 8).

Zidovudine

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%, 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. 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 received placebo. The observed abnormalities included problems in embryogenesis (prior to 14 weeks) or were recognized on ultrasound before or immediately after initiation of trial drug. See full prescribing information for RETROVIR® (zidovudine) and COMBIVIR® (lamivudine and zidovudine).

Zidovudine has been shown to cross the placenta and concentrations in neonatal plasma at birth were essentially equal to those in maternal plasma at delivery [see CLINICAL PHARMACOLOGY (12.3)].

Animal Data:

Abacavir

Abacavir was administered orally to pregnant rats (at 100, 300, and 1,000 mg per kg per day) and rabbits (at 125, 350, or 700 mg per kg per day) during organogenesis (on gestation Days 6 through 17 and 6 through 20, respectively). Fetal malformations (increased incidences of fetal anasarca and skeletal malformations) or developmental toxicity (decreased fetal body weight and crown-rump length) were observed in rats at doses up to 1,000 mg per kg per day, resulting in exposures approximately 35 times the human exposure (AUC) at the recommended daily dose. No developmental effects were observed in rats at 100 mg per kg per day, resulting in exposures (AUC) 3.5 times the human exposure at the recommended daily dose. In a fertility and early embryo-fetal development study conducted in rats (at 60, 160, or 500 mg per kg per day), embryonic and fetal toxicities (increased resorptions, decreased fetal body weights) or toxicities to the offspring (increased incidence of stillbirth and lower body weights) occurred at doses up to 500 mg per kg per day. No developmental effects were observed in rats at 60 mg per kg per day, resulting in exposures (AUC) approximately 4 times the human exposure at the recommended daily dose. Studies in pregnant rats showed that abacavir is transferred to the fetus through the placenta. In pregnant rabbits, no developmental toxicities and no increases in fetal malformations occurred at up to the highest dose evaluated, resulting in exposures (AUC) approximately 9 times the human exposure at the recommended dose.

Lamivudine

Lamivudine was administered orally to pregnant rats (at 90, 600, and 4,000 mg per kg per day) and rabbits (at 90, 300, and 1,000 mg per kg per day and at 15, 40, and 90 mg per kg per day) during organogenesis (on gestation Days 7 through 16 [rat] and 8 through 20 [rabbit], respectively). No evidence of fetal malformations due to lamivudine was observed in rats and rabbits at doses producing plasma concentrations (Cmax) approximately 35 times higher than human exposure at the recommended daily dose. Evidence of early embryolethality was seen in the rabbit at systemic exposures (AUC) similar to those observed in humans, but there was no indication of this effect in the rat at plasma concentrations (Cmax) 35 times higher than human exposure at the recommended daily dose. Studies in pregnant rats showed that lamivudine is transferred to the fetus through the placenta. In the pre-and postnatal development study in rats, lamivudine was administered orally at doses of 180, 900, and 4,000 mg per kg per day (from gestation Day 6 through postnatal Day 20). In the study, development of the offspring, including fertility and reproductive performance, was not affected by maternal administration of lamivudine.

Zidovudine

A study in pregnant rats (at 50, 150, or 450 mg per kg per day starting 26 days prior to mating through gestation to postnatal Day 21) showed increased fetal resorptions at doses that produced systemic exposures (AUC) approximately 33 times higher than exposure at the recommended daily human dose (300 mg twice daily). However, in an oral embryo-fetal development study in rats (at 125, 250, or 500 mg per kg per day on gestation Days 6 through 15), no fetal resorptions were observed at doses that produced systemic exposure (AUC) approximately 117 times higher than exposures at the recommended daily human dose. An oral embryo-fetal development study in rabbits (at 75, 150, or 500 mg per kg per day on gestation Days 6 through 18) showed increased fetal resorptions at the 500-mg-per-kg-per-day dose which produced systemic exposures (AUC) approximately 108 times higher than exposure at the recommended daily human dose; however, no fetal resorptions were noted at doses up to 150 mg per kg per day, which produced systemic exposure (AUC) approximately 23 times higher than exposures at the recommended daily human dose. These oral embryo-fetal development studies in the rat and rabbit revealed no evidence of fetal malformations with zidovudine. In another developmental toxicity study, pregnant rats (dosed at 3,000 mg per kg per day from Days 6 through 15 of gestation) showed marked maternal toxicity and an increased incidence of fetal malformations at exposures greater than 300 times the recommended daily human dose based on AUC. However, there were no signs of fetal malformations at doses up to 600 mg per kg per day.

Lactation

Risk Summary

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. Abacavir, lamivudine and zidovudine are present in human milk. There is no information on the effects of abacavir, lamivudine and zidovudine on the breastfed infant or the effects of the drug on milk production. Because of the potential for (1) HIV-1 transmission (in HIV-negative infants), (2) developing viral resistance (in HIV-positive infants), and (3) serious adverse reactions in a breastfed infant, instruct mothers not to breastfeed if they are receiving abacavir, lamivudine and zidovudine tablets.

Pediatric Use

Abacavir, lamivudine and zidovudine tablet is not recommended in children who weigh less than 40 kg because it is a fixed-dose tablet that cannot be adjusted for these patient populations [see DOSAGE AND ADMINISTRATION (2.3)].

Therapy-Experienced Pediatric Trial

A randomized, double-blind trial, CNA3006, compared ZIAGEN® plus lamivudine and zidovudine versus lamivudine and zidovudine in pediatric subjects, most of whom were extensively pretreated with nucleoside analogue antiretroviral agents. Subjects in this trial had a limited response to abacavir.

Geriatric Use

Clinical trials of abacavir, 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, caution should be exercised in the administration of abacavir, lamivudine and zidovudine tablets in elderly patients reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy [see CLINICAL PHARMACOLOGY (12.3)].

Patients with Impaired Renal Function

Abacavir, lamivudine and zidovudine tablet is not recommended for patients with creatinine clearance less than 50 mL per min because abacavir, lamivudine and zidovudine tablet is a fixed-dose combination and the dosage of the individual components cannot be adjusted. If a dose reduction of the lamivudine or zidovudine components of abacavir, lamivudine and zidovudine tablet is required for patients with renal impairment then the individual components should be used [see DOSAGE AND ADMINISTRATION (2.3), CLINICAL PHARMACOLOGY (12.3)].

Patients with Impaired Hepatic Function

Abacavir, lamivudine and zidovudine tablet is a fixed-dose combination and the dosage of the individual components cannot be adjusted. If a dose reduction of abacavir, a component of abacavir, lamivudine and zidovudine tablet, is required for patients with mild hepatic impairment (Child-Pugh Class A), then the individual components should be used [see CLINICAL PHARMACOLOGY (12.3)].

The safety, efficacy, and pharmacokinetic properties of abacavir have not been established in patients with moderate (Child-Pugh Class B) or severe (Child-Pugh Class C) hepatic impairment; therefore, abacavir, lamivudine and zidovudine tablets are contraindicated in these patients [see CONTRAINDICATIONS (4)].

Zidovudine is primarily eliminated by hepatic metabolism and zidovudine concentrations are increased in patients with impaired hepatic function, which may increase the risk of hematologic toxicity. Frequent monitoring of hematologic toxicities is advised.

Abacavir, Lamivudine and ZidovudineTablets Description

Abacavir, lamivudine and zidovudine tablets contain the following 3 synthetic nucleoside analogues: abacavir (ZIAGEN®), lamivudine (also known as EPIVIR® or 3TC), and zidovudine (also known as RETROVIR®, azidothymidine, or ZDV) with inhibitory activity against HIV-1.

Abacavir, lamivudine and zidovudine tablets are for oral administration. Each film-coated tablet contains the active ingredients 300 mg of abacavir as abacavir sulfate, 150 mg of lamivudine, and 300 mg of zidovudine, and the inactive ingredients crospovidone, magnesium stearate, microcrystalline cellulose, povidone, and yellow ferric oxide. The tablets are coated with a film opadry green that is made of FD&C blue no. 2, polyethylene glycol, polyvinyl alcohol, talc, titanium dioxide and yellow ferric oxide.

Abacavir Sulfate

The chemical name of abacavir sulfate is (1S,cis)-4-[2-amino-6-(cyclopropylamino)-9H-purin-9-yl]-2-cyclopentene-1-methanol sulfate (salt) (2:1). Abacavir sulfate is the enantiomer with 1S, 4R absolute configuration on the cyclopentene ring. It has a molecular formula of (C14H18N6O)2·H2SO4 and a molecular weight of 670.74 g per mol. It has the following structural formula:

Abacavir sulfate is a white to off-white powder and soluble in water. Dosages are expressed in terms of abacavir.

Lamivudine

The chemical name of lamivudine is (2R,cis)-4-amino-1-(2-hydroxymethyl-1,3-oxathiolan-5-yl)-(1H)-pyrimidin-2-one, 0.2 hydrate. 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 C8H11N3O3S·0.2H2O and a molecular weight of 232.86 g per mol. It has the following structural formula:

Lamivudine is a white to off-white solid and is soluble in water.

Zidovudine

The chemical name of zidovudine is 3'-azido-3'-deoxythymidine. It has a molecular formula of C10H13N5O4 and a molecular weight of 267.24 g per mol. It has the following structural formula:

Zidovudine is a white to yellowish powder with a solubility of 20.1 mg/mL in water at 25°C.

For the Consumer

Applies to abacavir / lamivudine / zidovudine: oral tablet

Along with its needed effects, abacavir / lamivudine / zidovudine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking abacavir / lamivudine / zidovudine:

More common
  • Chills
Less common
  • Abdominal or stomach pain
  • cough
  • diarrhea
  • fever
  • headache
  • muscle weakness
  • nausea
  • numbness or tingling of the face, feet, or hands
  • pain in the joints
  • pain in the muscles
  • pale skin
  • skin rash
  • sore throat
  • swelling of the feet or lower legs
  • unusual feeling of discomfort or illness
  • unusual tiredness or weakness
  • vomiting
  • yellow eyes or skin
Rare
  • Black, tarry stools
  • blood in the urine or stools
  • pinpoint red spots on the skin
  • unusual bleeding or bruising

Some side effects of abacavir / lamivudine / zidovudine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Bone pain
  • loss of appetite
  • trouble sleeping

Usual Adult Dose for HIV Infection

1 tablet orally twice a day

Use: In combination with other antiretroviral agents or alone, for the treatment of HIV-1 infection

Usual Adult Dose for Nonoccupational Exposure

US CDC recommendations: 1 tablet orally twice a day
Duration of therapy: 28 days

Comments:
-Recommended as an alternative regimen for nonoccupational postexposure prophylaxis of HIV infection; this triple NRTI regimen is recommended only when a NNRTI-based or a protease inhibitor-based regimen cannot or should not be used.
-Prophylaxis should be started as soon as possible, within 72 hours of exposure.
-Current guidelines should be consulted for additional information.

Renal Dose Adjustments

CrCl less than 50 mL/min: Not recommended; individual components should be used.

Abacavir / lamivudine / zidovudine Pregnancy Warnings

AU: Use is not recommended. UK, US: This drug should be used during pregnancy only if the benefit outweighs the risk. AU TGA pregnancy category: B3 US FDA pregnancy category: C Comments: -A pregnancy exposure registry is available.

Animal studies with abacavir (high-dose) have revealed evidence of embryonic and fetal toxicity, including developmental toxicity, fetal anasarca, skeletal malformations, and increased incidence of stillbirth. Animal studies with lamivudine have failed to reveal evidence of teratogenicity; while early embryolethality was observed in rabbit studies (exposure levels similar to human levels), this effect was not seen in high-dose studies in rats. Animal studies with zidovudine have failed to reveal evidence of teratogenicity; some high-dose studies demonstrated an increased incidence of fetal resorption. Placental transfer of each drug has been observed in humans. Data on pregnant women using abacavir, lamivudine, and zidovudine together as the individual components, abacavir, lamivudine, and zidovudine (more than 300, 600, 3000, and 3000 outcomes from first trimester exposures, respectively; more than 2000 of the 3000 outcomes had exposure to both lamivudine and zidovudine) showed no malformative toxicity. There are no controlled data in human pregnancy with this combination drug. To monitor maternal-fetal outcomes of pregnant women exposed to antiretroviral therapy, an Antiretroviral Pregnancy Registry (APR) has been established. Healthcare providers are encouraged to prospectively register patients. For additional information: apregistry.com The APR has received prospective reports of over 2000 exposures to abacavir (over 900 exposed in the first trimester), over 11,000 exposures to lamivudine (over 4300 exposed in the first trimester), and over 13,000 exposures to zidovudine (over 4000 exposed in the first trimester) resulting in live births; there was no difference between abacavir, lamivudine, or zidovudine and overall birth defects compared with the background birth defect rate of 2.7% in the reference population. The prevalence of defects in the first trimester was 2.9% for abacavir, 3.1% for lamivudine, and 3.2% for zidovudine. No increased risk of major birth defects observed for these drugs compared to background rate. In 2 clinical trials, maternal, neonatal, and umbilical cord serum lamivudine levels were generally comparable. Amniotic fluid samples collected after natural rupture of membranes from a subset of patients confirmed placental transfer in humans. Amniotic fluid levels of lamivudine were usually 2 times greater than maternal serum levels, ranging from 1.2 to 2.5 mcg/mL (150 mg twice a day) and 2.1 to 5.2 mcg/mL (300 mg twice a day). In the trial AIDS Clinical Trial Group (ACTG) 076, perinatal administration of zidovudine was shown to reduce the transmission of HIV-1 from mother to infant by about two-thirds (7.8% compared to 24.9% with placebo; 363 neonates evaluated). Zidovudine had been initiated in HIV-1-infected women with a CD4+ cell count of 200 to 1818 cells/mm3 who had little or no prior exposure to zidovudine. Oral zidovudine was started between 14 and 34 weeks gestation followed by IV zidovudine during labor and delivery. For 6 weeks after birth, infants received oral zidovudine. Zidovudine was well tolerated by mothers and infants; there was no difference in pregnancy-related side effects between the treatment groups. Of 180 infants administered zidovudine during this study, the only fetal or infant toxicity reported was a mean decrease in hemoglobin of less than 1 g/dL, which resolved spontaneously after completion of therapy. Zidovudine crosses the placenta rapidly, with similar maternal serum and umbilical levels at delivery. Pregnancy does not significantly affect zidovudine pharmacokinetics. Several reports of zidovudine use in pregnancy, including during the first trimester, have not revealed teratogenicity or fetal toxicity, other than reversible anemia. No side effects were observed in HIV-uninfected children with in utero and neonatal exposure to zidovudine followed up for as long as 5.6 years. One series of 104 cases of intentional or inadvertent use of zidovudine during all stages of pregnancy was unable to demonstrate any specific abnormalities reasonably attributable to zidovudine use. Anomalies reported in infants exposed during the first trimester included low set ears, retrognathia, prominent epicanthal folds, hirsutism, triangular facies with blue sclera, hyperpigmented skin macules, prominent sacral dimple in 1 infant, multiple minor anomalies in 1 infant, and extra digits in 1 infant. Pectus excavatum was reported in 2 infants exposed in the second and third trimesters. An infant exposed during the third trimester exhibited albinism, congenital ptosis, oligohydramnios and intrauterine growth retardation. AU TGA pregnancy category B3: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have shown evidence of an increased occurrence of fetal damage, the significance of which is considered uncertain in humans. US FDA pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

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