Atripla (Page 5 of 12)

Emtricitabine: No postmarketing adverse reactions have been identified for inclusion in this section.

Tenofovir Disoproxil Fumarate:

Immune System Disorders
Allergic reaction, including angioedema

Metabolism and Nutrition Disorders
Lactic acidosis, hypokalemia, hypophosphatemia

Respiratory, Thoracic, and Mediastinal Disorders
Dyspnea

Gastrointestinal Disorders
Pancreatitis, increased amylase, abdominal pain

Hepatobiliary Disorders
Hepatic steatosis, hepatitis, increased liver enzymes (most commonly AST, ALT, gamma GT)

Skin and Subcutaneous Tissue Disorders
Rash

Musculoskeletal and Connective Tissue Disorders
Rhabdomyolysis, osteomalacia (manifested as bone pain and which may contribute to fractures), muscular weakness, myopathy

Renal and Urinary Disorders
Acute renal failure, renal failure, acute tubular necrosis, Fanconi syndrome, proximal renal tubulopathy, interstitial nephritis (including acute cases), nephrogenic diabetes insipidus, renal insufficiency, increased creatinine, proteinuria, polyuria

General Disorders and Administration Site ConditionsAsthenia

The following adverse reactions, listed under the body system headings above, may occur as a consequence of proximal renal tubulopathy: rhabdomyolysis, osteomalacia, hypokalemia, muscular weakness, myopathy, hypophosphatemia.

7 DRUG INTERACTIONS

This section describes clinically relevant drug interactions with ATRIPLA. Drug interaction studies are described elsewhere in the labeling [see Clinical Pharmacology (12.3) ].

7.1 Efavirenz

Efavirenz has been shown in vivo to induce CYP3A. Other compounds that are substrates of CYP3A may have decreased plasma concentrations when coadministered with efavirenz. In vitro studies have demonstrated that efavirenz inhibits CYP2C9, 2C19, and 3A4 isozymes in the range of observed efavirenz plasma concentrations. Coadministration of efavirenz with drugs primarily metabolized by these isozymes may result in altered plasma concentrations of the coadministered drug. Therefore, appropriate dose adjustments may be necessary for these drugs.

Drugs that induce CYP3A activity (e.g., phenobarbital, rifampin, rifabutin) would be expected to increase the clearance of efavirenz resulting in lowered plasma concentrations.

7.2 Emtricitabine and Tenofovir Disoproxil Fumarate

Since emtricitabine and tenofovir are primarily eliminated by the kidneys, coadministration of ATRIPLA with drugs that reduce renal function or compete for active tubular secretion may increase serum concentrations of emtricitabine, tenofovir, and/or other renally eliminated drugs. Some examples include, but are not limited to, acyclovir, adefovir dipivoxil, cidofovir, ganciclovir, valacyclovir, and valganciclovir.

Coadministration of tenofovir DF and didanosine should be undertaken with caution and patients receiving this combination should be monitored closely for didanosine-associated adverse reactions. Didanosine should be discontinued in patients who develop didanosine-associated adverse reactions [for didanosine dosing adjustment recommendations, see Table 4]. Suppression of CD4+ cell counts has been observed in patients receiving tenofovir DF with didanosine 400 mg daily.

Lopinavir/ritonavir has been shown to increase tenofovir concentrations. The mechanism of this interaction is unknown. Patients receiving lopinavir/ritonavir with ATRIPLA should be monitored for tenofovir-associated adverse reactions. ATRIPLA should be discontinued in patients who develop tenofovir-associated adverse reactions [See Table 4 ].

Coadministration of atazanavir with ATRIPLA is not recommended since coadministration of atazanavir with either efavirenz or tenofovir DF has been shown to decrease plasma concentrations of atazanavir. Also, atazanavir has been shown to increase tenofovir concentrations. There are insufficient data to support dosing recommendations for atazanavir or atazanavir/ritonavir in combination with ATRIPLA [See Table 4 ].

7.3 Efavirenz, Emtricitabine and Tenofovir Disoproxil Fumarate

Other important drug interaction information for ATRIPLA is summarized in Table 1 and Table 4. The drug interactions described are based on studies conducted with efavirenz, emtricitabine or tenofovir DF as individual agents or are potential drug interactions; no drug interaction studies have been conducted using ATRIPLA [for pharmacokinetics data see Clinical Pharmacology (12.3), Tables 5–9]. The tables include potentially significant interactions, but are not all inclusive.

Table 4 Established and Other Potentially Significant * Drug Interactions: Alteration in Dose or Regimen May Be Recommended Based on Drug Interaction Studies or Predicted Interaction
Concomitant Drug Class: Drug Name Effect Clinical Comment
*
This table is not all inclusive.
Antiretroviral agents
Protease inhibitor: atazanavir ↓atazanavir concentration ↑ tenofovir concentration Coadministration of atazanavir with ATRIPLA is not recommended. Coadministration of atazanavir with either efavirenz or tenofovir DF decreases plasma concentrations of atazanavir. The combined effect of efavirenz plus tenofovir DF on atazanavir plasma concentrations is not known. Also, atazanavir has been shown to increase tenofovir concentrations. There are insufficient data to support dosing recommendations for atazanavir or atazanavir/ritonavir in combination with ATRIPLA.
Protease inhibitor: fosamprenavir calcium ↓ amprenavir concentration Fosamprenavir (unboosted): Appropriate doses of fosamprenavir and ATRIPLA with respect to safety and efficacy have not been established. Fosamprenavir/ritonavir: An additional 100 mg/day (300 mg total) of ritonavir is recommended when ATRIPLA is administered with fosamprenavir/ritonavir once daily. No change in the ritonavir dose is required when ATRIPLA is administered with fosamprenavir plus ritonavir twice daily.
Protease inhibitor: indinavir ↓ indinavir concentration The optimal dose of indinavir, when given in combination with efavirenz, is not known. Increasing the indinavir dose to 1000 mg every 8 hours does not compensate for the increased indinavir metabolism due to efavirenz.
Protease inhibitor: lopinavir/ritonavir ↓ lopinavir concentration ↑ tenofovir concentration A dose increase of lopinavir/ritonavir to 600/150 mg (3 tablets) twice daily may be considered when used in combination with efavirenz in treatment-experienced patients where decreased susceptibility to lopinavir is clinically suspected (by treatment history or laboratory evidence). Patients should be monitored for tenofovir-associated adverse reactions. ATRIPLA should be discontinued in patients who develop tenofovir-associated adverse reactions.
Protease inhibitor: ritonavir ↑ ritonavir concentration ↑ efavirenz concentration When ritonavir 500 mg every 12 hours was coadministered with efavirenz 600 mg once daily, the combination was associated with a higher frequency of adverse clinical experiences (e.g., dizziness, nausea, paresthesia) and laboratory abnormalities (elevated liver enzymes). Monitoring of liver enzymes is recommended when ATRIPLA is used in combination with ritonavir.
Protease inhibitor: saquinavir ↓ saquinavir concentration Should not be used as sole protease inhibitor in combination with ATRIPLA.
NRTI: didanosine ↑ didanosine concentration Higher didanosine concentrations could potentiate didanosine-associated adverse reactions, including pancreatitis and neuropathy. In adults weighing >60 kg, the didanosine dose should be reduced to 250 mg if coadministered with ATRIPLA. Data are not available to recommend a dose adjustment of didanosine for patients weighing <60 kg. Coadministration of ATRIPLA and didanosine should be undertaken with caution and patients receiving this combination should be monitored closely for didanosine-associated adverse reactions. For additional information, please consult the Videx / Videx EC (didanosine) prescribing information.
Other agents
Anticoagulant: warfarin ↑ or ↓ warfarin concentration Plasma concentrations and effects potentially increased or decreased by efavirenz.
Anticonvulsants: carbamazepine ↓ carbamazepine concentration ↓ efavirenz concentration There are insufficient data to make a dose recommendation for ATRIPLA. Alternative anticonvulsant treatment should be used.
phenytoin phenobarbital ↓ anticonvulsant concentration ↓ efavirenz concentration Potential for reduction in anticonvulsant and/or efavirenz plasma levels; periodic monitoring of anticonvulsant plasma levels should be conducted.
Antidepressant: sertraline ↓ sertraline concentration Increases in sertraline dose should be guided by clinical response.
Antifungals: itraconazole ↓ itraconazole concentration ↓ hydroxy-itraconazole concentration Since no dose recommendation for itraconazole can be made, alternative antifungal treatment should be considered.
ketoconazole ↓ ketoconazole concentration Drug interaction studies with ATRIPLA and ketoconazole have not been conducted. Efavirenz has the potential to decrease plasma concentrations of ketoconazole.
Anti-infective: clarithromycin ↓ clarithromycin concentration ↑ 14-OH metabolite concentration Clinical significance unknown. In uninfected volunteers, 46% developed rash while receiving efavirenz and clarithromycin. No dose adjustment of ATRIPLA is recommended when given with clarithromycin. Alternatives to clarithromycin, such as azithromycin, should be considered. Other macrolide antibiotics, such as erythromycin, have not been studied in combination with ATRIPLA.
Antimycobacterial: rifabutin ↓ rifabutin concentration Increase daily dose of rifabutin by 50%. Consider doubling the rifabutin dose in regimens where rifabutin is given 2 or 3 times a week.
Antimycobacterial: rifampin ↓ efavirenzconcentration Clinical significance of reduced efavirenz concentration is unknown. Dosing recommendations for concomitant use of ATRIPLA and rifampin have not been established.
Calcium channel blockers: diltiazem ↓ diltiazem concentration ↓ desacetyl diltiazem concentration ↓ N-monodes-methyl diltiazem concentration Diltiazem dose adjustments should be guided by clinical response (refer to the prescribing information for diltiazem). No dose adjustment of ATRIPLA is necessary when administered with diltiazem.
Others (e.g., felodipine, nicardipine, nifedipine, verapamil) ↓ calcium channel blocker No data are available on the potential interactions of efavirenz with other calcium channel blockers that are substrates of CYP3A. The potential exists for reduction in plasma concentrations of the calcium channel blocker. Dose adjustments should be guided by clinical response (refer to the prescribing information for the calcium channel blocker).
HMG-CoA reductase inhibitors: atorvastatin pravastatin simvastatin ↓ atorvastatin concentration ↓ pravastatin concentration ↓ simvastatin concentration Plasma concentrations of atorvastatin, pravastatin, and simvastatin decreased with efavirenz. Consult the prescribing information for the HMG-CoA reductase inhibitor for guidance on individualizing the dose.
Hormonal contraceptives:
Oral: Ethinyl estradiol/Norgestimate ↓ active metabolites of norgestimate A reliable method of barrier contraception must be used in addition to hormonal contraceptives. Efavirenz had no effect on ethinyl estradiol concentrations, but progestin levels (norelgestromin and levonorgestrel) were markedly decreased. No effect of ethinyl estradiol/norgestimate on efavirenz plasma concentrations was observed.
Implant: Etonogestrel ↓ etonogestrel A reliable method of barrier contraception must be used in addition to hormonal contraceptives. The interaction between etonogestrel and efavirenz has not been studied. Decreased exposure of etonogestrel may be expected. There have been postmarketing reports of contraceptive failure with etonogestrel in efavirenz-exposed patients.
Immunosuppressants: Cyclosporine, tacrolimus, sirolimus, and others metabolized by CYP3A ↓ immuno-suppressant Decreased exposure of the immunosuppressant may be expected due to CYP3A induction by efavirenz. These immunosuppressants are not anticipated to affect exposure of efavirenz. Dose adjustments of the immunosuppressant may be required. Close monitoring of immunosuppressant concentrations for at least 2 weeks (until stable concentrations are reached) is recommended when starting or stopping treatment with ATRIPLA.
Narcotic analgesic: methadone ↓ methadone concentration Coadministration of efavirenz in HIV-1 infected individuals with a history of injection drug use resulted in decreased plasma levels of methadone and signs of opiate withdrawal. Methadone dose was increased by a mean of 22% to alleviate withdrawal symptoms. Patients should be monitored for signs of withdrawal and their methadone dose increased as required to alleviate withdrawal symptoms.

All MedLibrary.org resources are included in as near-original form as possible, meaning that the information from the original provider has been rendered here with only typographical or stylistic modifications and not with any substantive alterations of content, meaning or intent.

This site is provided for educational and informational purposes only, in accordance with our Terms of Use, and is not intended as a substitute for the advice of a medical doctor, nurse, nurse practitioner or other qualified health professional.

Privacy Policy | Copyright © 2022. All Rights Reserved.