The following adverse reactions have been identified during postapproval use of ISENTRESS. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Blood and Lymphatic System Disorders: thrombocytopenia
Gastrointestinal Disorders: diarrhea
Hepatobiliary Disorders: hepatic failure (with and without associated hypersensitivity) in patients with underlying liver disease and/or concomitant medications
Musculoskeletal and Connective Tissue Disorders: rhabdomyolysis
Nervous System Disorders: cerebellar ataxia
Psychiatric Disorders: anxiety, paranoia
Raltegravir is not a substrate of cytochrome P450 (CYP) enzymes. Based on in vivo and in vitro studies, raltegravir is eliminated mainly by metabolism via a UGT1A1-mediated glucuronidation pathway. Coadministration of ISENTRESS with drugs that inhibit UGT1A1 may increase plasma levels of raltegravir and coadministration of ISENTRESS with drugs that induce UGT1A1, such as rifampin, may reduce plasma levels of raltegravir (see Table 11).
Selected drug interactions are presented in Table 11 [see Clinical Pharmacology (12.3)] . In some cases, recommendations differ for ISENTRESS versus ISENTRESS HD.
|Concomitant Drug Class: Drug Name||Effect on Concentration of Raltegravir||Clinical Comment for ISENTRESS||Clinical Comment for ISENTRESS HD|
|Aluminum and/or magnesium-containing antacids||↓||Coadministration or staggered administration is not recommended.|
|Calcium carbonate antacid||↓||No dose adjustment||Co-administration is not recommended|
|Rifampin||↓||The recommended dosage is 800 mg twice daily during coadministration with rifampin. There are no data to guide co-administration of ISENTRESS with rifampin in patients below 18 years of age [see Dosage and Administration (2.1)].||Coadministration is not recommended.|
|Tipranavir/ritonavir||No dose adjustment||Coadministration is not recommended|
|Etravirine||↓||No dose adjustment||Coadministration is not recommended.|
|Strong inducers of drug metabolizing enzymes not mentioned above e.g., Carbamazepine Phenobarbital Phenytoin||↓↔||The impact of other strong inducers of drug metabolizing enzymes on raltegravir is unknown. Coadministration is not recommended.|
In drug interaction studies performed using ISENTRESS film-coated tablets 400 mg twice daily dose, raltegravir did not have a clinically meaningful effect on the pharmacokinetics of the following: ethinyl estradiol/norgestimate, methadone, midazolam, lamivudine, tenofovir disoproxil fumarate, etravirine, darunavir/ritonavir, or boceprevir. Moreover, atazanavir, atazanavir/ritonavir, boceprevir, calcium carbonate antacids, darunavir/ritonavir, efavirenz, etravirine, omeprazole, or tipranavir/ritonavir did not have a clinically meaningful effect on the pharmacokinetics of 400 mg twice daily raltegravir. No dose adjustment is required when ISENTRESS 400 mg twice daily is coadministered with these drugs.
There is no predicted pharmacokinetic drug interaction between ISENTRESS and tenofovir alafenamide.
In drug interaction studies, efavirenz did not have a clinically meaningful effect on the pharmacokinetics of ISENTRESS HD 1200 mg (2 × 600 mg) once daily. No dose adjustment is recommended when ISENTRESS HD 1200 mg once daily is coadministered with atazanavir, atazanavir/ritonavir, hormonal contraceptives, methadone, lamivudine, tenofovir disoproxil fumarate, darunavir/ritonavir, boceprevir, efavirenz and omeprazole.
There is no predicted pharmacokinetic drug interaction between ISENTRESS HD and tenofovir alafenamide.
Pregnancy Exposure Registry
There is a pregnancy exposure registry that monitors pregnancy outcomes in women. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263.
Available data from the APR show no difference in the rate of overall birth defects for raltegravir compared to the background rate for major birth defects of 2.7% in the U.S. reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP) (see Data) . 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 15-20%. The background risk for major birth defects and miscarriage for the indicated population is unknown. Methodological limitations of the APR include the use of MACDP as the external comparator group. The MACDP population is not disease-specific, evaluates women and infants from a limited geographic area, and does not include outcomes for births that occurred at <20 weeks gestation (see Data).
In animal reproduction studies in rats and rabbits, no evidence of adverse developmental outcomes was observed with oral administration of raltegravir during organogenesis at doses that produced exposures up to approximately 4 times the maximal recommended human dose (MRHD) of 1200 mg (see Data) .
Based on prospective reports from the APR of over 500 exposures to raltegravir during pregnancy resulting in live births (including over 250 exposures in the first trimester), there was no difference between the overall risk of birth defects for raltegravir compared with the background birth defect rate of 2.7% in the U.S. reference population of the MACDP. The prevalence of defects in live births was 2.9% (95% CI: 1.2% to 5.6%) following first trimester exposure to raltegravir-containing regimens and 3.6% (95% CI: 1.6% to 6.6%) following second and third trimester exposure to raltegravir-containing regimens.
In a combined embryo/fetal and pre/postnatal development study, raltegravir was administered orally to rats at doses of 100, 300, 600 mg/kg/day on gestation day 6 to 20 or from gestation day 6 to lactation day 20. No effects on pre/postnatal development were observed up to the highest dose tested. Embryo-fetal findings were limited to an increase in the incidence of supernumerary ribs in the 600 mg/kg/day group. Systemic exposure (AUC) at 600 mg/kg/day was approximately 3 times higher than exposure at the MRHD of 1200 mg.
In pregnant rabbits, raltegravir was administered orally at doses of 100, 500, or 1000 mg/kg/day during the gestation days 7 to 20. No embryo/fetal effects were noted up to the highest dose of 1000 mg/kg/day. Systemic exposure (AUC) at 1000 mg/kg/day was approximately 4 times higher than exposures at the MRHD of 1200 mg. In both species, raltegravir has been shown to cross the placenta, with fetal plasma concentrations observed in rats approximately 1.5 to 2.5 times greater than in maternal plasma and fetal plasma concentrations in rabbits approximately 2% that of maternal concentrations on gestation day 20.
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