Atazanavir (Page 6 of 12)

7.4 Drugs with No Observed Interactions with Atazanavir

No clinically significant drug interactions were observed when atazanavir was co-administered with methadone, fluconazole, acetaminophen, atenolol, or the nucleoside reverse transcriptase inhibitors lamivudine or zidovudine [see Clinical Pharmacology, Tables 21 and 22 (12.3)].

8 USE IN SPECIFIC POPULATIONS

8.1 Pregnancy

Pregnancy Exposure Registry

There is a pregnancy exposure registry that monitors pregnancy outcomes in patients exposed to atazanavir during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263.

Risk Summary

Atazanavir has been evaluated in a limited number of women during pregnancy. Available human and animal data suggest that atazanavir does not increase the risk of major birth defects overall compared to the background rate [see Data]. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. No treatment-related malformations were observed in rats and rabbits, for which the atazanavir exposures were 0.7 to 1.2 times of those at the human clinical dose (300 mg/day atazanavir boosted with 100 mg/day ritonavir). When atazanavir was administered to rats during pregnancy and throughout lactation, reversible neonatal growth retardation was observed [see Data].

Clinical Considerations

Dose Adjustments during Pregnancy and the Postpartum Period

  • Atazanavir must be administered with ritonavir in pregnant patients.
  • For pregnant patients, no dosage adjustment is required for atazanavir with the following exceptions:
  • For treatment-experienced pregnant women during the second or third trimester, when atazanavir is co-administered with either an H2 -receptor antagonist or tenofovir DF, atazanavir 400 mg with ritonavir 100 mg once daily is recommended. There are insufficient data to recommend a atazanavir dose for use with both an H2 -receptor antagonist and tenofovir DF in treatment-experienced pregnant patients.
  • No dosage adjustment is required for postpartum patients. However, patients should be closely monitored for adverse events because atazanavir exposures could be higher during the first 2 months after delivery [see Dosage and Administration (2.6) and Clinical Pharmacology (12.3)].

Maternal Adverse Reactions

Cases of lactic acidosis syndrome, sometimes fatal, and symptomatic hyperlactatemia have occurred in pregnant women using atazanavir in combination with nucleoside analogues, which are associated with an increased risk of lactic acidosis syndrome.

Hyperbilirubinemia occurs frequently in patients who take atazanavir [see Warnings and Precautions (5.8)] , including those who are pregnant [see Data].

Advise pregnant women of the potential risks of lactic acidosis syndrome and hyperbilirubinemia.

Fetal/Neonatal Adverse Reactions

All infants, including neonates exposed to atazanavir in utero , should be monitored for the development of severe hyperbilirubinemia during the first few days of life [see Data].

Data

Human Data

In Study AI424-182, atazanavir with ritonavir (300/100 mg or 400/100 mg) co-administered with lamivudine/zidovudine (150 mg/ 300 mg, as fixed-dose product) was administered to 41 pregnant women with HIV-1 infection, during the second or third trimester. Among the 39 women who completed the study, 38 women achieved an HIV-1 RNA less than 50 copies/mL at time of delivery. Six of 20 (30%) women on atazanavir with ritonavir 300/100 mg and 13 of 21 (62%) women on atazanavir with ritonavir 400/100 mg experienced hyperbilirubinemia (total bilirubin greater than or equal to 2.6 times ULN). There were no cases of lactic acidosis observed in clinical trial AI424-182.

Atazanavir drug concentrations in fetal umbilical cord blood were approximately 12% to 19% of maternal concentrations. Among the 40 infants born to 40 pregnant women with HIV-1 infection, all had test results that were negative for HIV-1 DNA at the time of delivery and/or during the first 6 months postpartum. All 40 infants received antiretroviral prophylactic treatment containing zidovudine. No evidence of severe hyperbilirubinemia (total bilirubin levels greater than 20 mg/dL) or acute or chronic bilirubin encephalopathy was observed among neonates in this study. However, 10/36 (28%) infants (6 greater than or equal to 38 weeks gestation and 4 less than 38 weeks gestation) had bilirubin levels of 4 mg/dL or greater within the first day of life.

Lack of ethnic diversity was a study limitation. In the study population, 33/40 (83%) infants were Black/African American, who have a lower incidence of neonatal hyperbilirubinemia than Caucasians and Asians. In addition, women with Rh incompatibility were excluded, as well as women who had a previous infant who developed hemolytic disease and/or had neonatal pathologic jaundice (requiring phototherapy).

Additionally, of the 38 infants who had glucose samples collected in the first day of life, 3 had adequately collected serum glucose samples with values of less than 40 mg/dL that could not be attributed to maternal glucose intolerance, difficult delivery, or sepsis.

Based on prospective reports from the APR of approximately 1,600 live births following exposure to atazanavir-containing regimens (including 1,037 live births in infants exposed in the first trimester and 569 exposed in second/third trimesters), there was no difference between atazanavir and overall birth defects compared with the background birth defect rate. In the U.S. general population, the estimated background risk of major birth defects in clinically recognized pregnancies is 2% to 4%.

Animal Data

In animal reproduction studies, there was no evidence of mortality or teratogenicity in offspring born to animals at systemic drug exposure levels (AUC) 0.7 (in rabbits) to 1.2 (in rats) times those observed at the human clinical dose (300 mg/day atazanavir boosted with 100 mg/day ritonavir). In pre- and postnatal development studies in the rat, atazanavir caused neonatal growth retardation during lactation that reversed after weaning. Maternal drug exposure at this dose was 1.3 times the human exposure at the recommended clinical exposure. Minimal maternal toxicity occurred at this exposure level.

8.2 Lactation

Risk Summary

The Centers for Disease Control and Prevention recommend that patients with HIV-1 infection, not breastfeed their infants to avoid risking postnatal transmission of HIV-1. Atazanavir has been detected in human milk. No data are available regarding atazanavir effects on milk production. Atazanavir was present in the milk of lactating rats and was associated with neonatal growth retardation that reversed after weaning.

Because of both the potential for HIV-1 transmission and the potential for serious adverse reactions in breastfed infants, advise women not to breastfeed.

8.4 Pediatric Use

Atazanavir is indicated in combination with other antiretroviral agents for the treatment of pediatric patients with HIV-1 infection, 6 years of age and older weighing at least 15 kg. Atazanavir is not recommended for use in pediatric patients below the age of 3 months due to the risk of kernicterus [see Indications and Usage (1)]. All atazanavir contraindications, warnings, and precautions apply to pediatric patients [see Contraindications (4) and Warnings and Precautions (5)].

The safety, pharmacokinetic profile, and virologic response of atazanavir in pediatric patients at least 6 years of age and older weighing at least 15 kg were established in an open-label, multicenter clinical trial: PACTG 1020A [see Clinical Pharmacology (12.3) and Clinical Studies (14.3)]. The safety profile in pediatric patients was generally similar to that observed in adults [see Adverse Reactions (6.1)]. See Dosage and Administration (2.4) for dosing recommendations for the use of atazanavir capsules in pediatric patients.

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