home > drugs a-z list > atripla (efavirenz, emtricitabine, and tenofovir disoproxil fumarate) drug center > atripla (efavirenz, emtricitabine, and tenofovir disoproxil fumarate) drug - side effects and drug interactions

Efavirenz, Emtricitabine and Tenofovir Disoproxil Fumarate: The following adverse reactions are discussed in other sections of the labeling:

• Lactic Acidosis/Severe Hepatomegaly with Steatosis [See BOXED WARNING, WARNINGS AND PRECAUTIONS].
• Severe Acute Exacerbations of Hepatitis B [See BOXED WARNING, WARNINGS AND PRECAUTIONS].
• Psychiatric Symptoms [See WARNINGS AND PRECAUTIONS].
• Nervous System Symptoms [See WARNINGS AND PRECAUTIONS].
• New Onset or Worsening Renal Impairment [See WARNINGS AND PRECAUTIONS].
• Rash [See WARNINGS AND PRECAUTIONS].
• Hepatotoxicity [See WARNINGS AND PRECAUTIONS].
• Decreases in Bone Mineral Density [See WARNINGS AND PRECAUTIONS].
• Immune Reconstitution Syndrome [See WARNINGS AND PRECAUTIONS].
• Drug Interactions [See CONTRAINDICATIONS, WARNINGS AND PRECAUTIONS and DRUG INTERACTIONS].

For additional safety information about SUSTIVA (efavirenz), EMTRIVA (emtricitabine), or VIREAD (tenofovir DF) in combination with other antiretroviral agents, consult the prescribing information for these products.

Adverse Reactions from 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.

Study 934

Study 934 was an open-label active-controlled trial in which 511 antiretroviral-naive subjects received either emtricitabine + tenofovir DF administered in combination with efavirenz (N=257) or zidovudine/lamivudine administered in combination with efavirenz (N=254).

The most common adverse reactions (incidence greater than or equal to 10%, any severity) occurring in Study 934 include diarrhea, nausea, fatigue, headache, dizziness, depression, insomnia, abnormal dreams, and rash. Adverse reactions observed in Study 934 were generally consistent with those seen in previous trials of the individual components (Table 2).

Table 2 : Selected Treatment-Emergent Adverse Reactionsa (Grades 2–4) Reported in ≥ 5% in Either Treatment Group in Study 934 (0–144 Weeks)

Study 073

In Study 073, subjects with stable, virologic suppression on antiretroviral therapy and no history of virologic failure were randomized to receive ATRIPLA or to stay on their baseline regimen. The adverse reactions observed in Study 073 were generally consistent with those seen in Study 934 and those seen with the individual components of ATRIPLA when each was administered in combination with other antiretroviral agents.

Efavirenz, Emtricitabine, or Tenofovir Disoproxil Fumarate

In addition to the adverse reactions in Study 934 and Study 073 the following adverse reactions were observed in clinical trials of efavirenz, emtricitabine, or tenofovir DF in combination with other antiretroviral agents.

Efavirenz: The most significant adverse reactions observed in subjects treated with efavirenz are nervous system symptoms [See WARNINGS AND PRECAUTIONS], psychiatric symptoms [See WARNINGS AND PRECAUTIONS], and rash [See WARNINGS AND PRECAUTIONS].

Selected adverse reactions of moderate-severe intensity observed in greater than or equal to 2% of efavirenz-treated subjects in two controlled clinical trials included pain, impaired concentration, abnormal dreams, somnolence, anorexia, dyspepsia, abdominal pain, nervousness, and pruritus.

Pancreatitis has also been reported, although a causal relationship with efavirenz has not been established. Asymptomatic increases in serum amylase levels were observed in a significantly higher number of subjects treated with efavirenz 600 mg than in control subjects.

Emtricitabine and Tenofovir Disoproxil Fumarate: Adverse reactions that occurred in at least 5% of treatment-experienced or treatment-naive subjects receiving emtricitabine or tenofovir DF with other antiretroviral agents in clinical trials include arthralgia, increased cough, dyspepsia, fever, myalgia, pain, abdominal pain, back pain, paresthesia, peripheral neuropathy (including peripheral neuritis and neuropathy), pneumonia, rhinitis and rash event (including rash, pruritus, maculopapular rash, urticaria, vesiculobullous rash, pustular rash and allergic reaction).

Skin discoloration has been reported with higher frequency among emtricitabine-treated subjects; it was manifested by hyperpigmentation on the palms and/or soles and was generally mild and asymptomatic. The mechanism and clinical significance are unknown.

Laboratory Abnormalities

Efavirenz, Emtricitabine and Tenofovir Disoproxil Fumarate: Laboratory abnormalities observed in Study 934 were generally consistent with those seen in previous trials (Table 3).

Table 3 : Significant Laboratory Abnormalities Reported in ≥ 1% of Subjects in Either Treatment Group in Study 934 (0–144 Weeks)

Laboratory abnormalities observed in Study 073 were generally consistent with those in Study 934.

In addition to the laboratory abnormalities described for Study 934 (Table 3), Grade 3/4 laboratory abnomalities of increased bilirubin ( > 2.5 x ULN), increased pancreatic amylase ( > 2.0 x ULN), increased or decreased serum glucose ( < 40 or > 250 mg/dL), and increased serum lipase ( > 2.0 x ULN) occurred in up to 3% of subjects treated with emtricitabine or tenofovir DF with other antiretroviral agents in clinical trials.

Hepatic Events: In Study 934, 19 subjects treated with efavirenz, emtricitabine, and tenofovir DF and 20 subjects treated with efavirenz and fixed-dose zidovudine/lamivudine were hepatitis B surface antigen or hepatitis C antibody positive. Among these coinfected subjects, one subject (1/19) in the efavirenz, emtricitabine and tenofovir DF arm had elevations in transaminases to greater than five times ULN through 144 weeks. In the fixed-dose zidovudine/lamivudine arm, two subjects (2/20) had elevations in transaminases to greater than five times ULN through 144 weeks. No HBV and/or HCV coinfected subject discontinued from the trial due to hepatobiliary disorders [See WARNINGS AND PRECAUTIONS].

Postmarketing Experience

The following adverse reactions have been identified during postapproval use of efavirenz, emtricitabine, or tenofovir DF. Because postmarketing 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.

Efavirenz

Cardiac Disorders

Palpitations

Ear and Labyrinth Disorders

Tinnitus, vertigo

Endocrine Disorders

Gynecomastia

Eye Disorders

Abnormal vision

Gastrointestinal Disorders

Constipation, malabsorption

General Disorders and Administration Site Conditions

Asthenia

Hepatobiliary Disorders

Hepatic enzyme increase, hepatic failure, hepatitis. A few of the postmarketing reports of hepatic failure, including cases in patients with no pre-existing hepatic disease or other identifiable risk factors, were characterized by a fulminant course, progressing in some cases to transplantation or death.

Immune System Disorders

Allergic reactions

Metabolism and Nutrition Disorders

Redistribution/accumulation of body fat [See WARNINGS AND PRECAUTIONS], hypercholesterolemia, hypertriglyceridemia

Musculoskeletal and Connective Tissue Disorders

Arthralgia, myalgia, myopathy

Nervous System Disorders

Abnormal coordination, ataxia, cerebellar coordination and balance disturbances, convulsions, hypoesthesia, paresthesia, neuropathy, tremor

Psychiatric Disorders

Aggressive reactions, agitation, delusions, emotional lability, mania, neurosis, paranoia, psychosis, suicide

Respiratory, Thoracic and Mediastinal Disorders

Dyspnea

Skin and Subcutaneous Tissue Disorders

Flushing, erythema multiforme, photoallergic dermatitis, Stevens-Johnson syndrome

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 Conditions

Asthenia

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.

This section describes clinically relevant drug interactions with ATRIPLA. Drug interaction trials are described elsewhere in the labeling [See CLINICAL PHARMACOLOGY].

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.

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 didanosineassociated 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].

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 trials conducted with efavirenz, emtricitabine or tenofovir DF as individual agents or are potential drug interactions; no drug interaction trials have been conducted using ATRIPLA [for pharmacokinetics data see CLINICAL PHARMACOLOGY, Tables 5-9]. The tables include potentially significant interactions, but are not all inclusive.

Table 4 : Established and Other Potentially Significant^a Drug Interactions: Alteration in Dose or Regimen May Be Recommended Based on Drug Interaction Trials or Predicted Interaction

Efavirenz Assay Interference

Cannabinoid Test Interaction: Efavirenz does not bind to cannabinoid receptors. False-positive urine cannabinoid test results have been observed in non-HIV-infected volunteers receiving efavirenz when the Microgenics Cedia DAU Multi-Level THC assay was used for screening. Negative results were obtained when more specific confirmatory testing was performed with gas chromatography/mass spectrometry. For more information, please consult the SUSTIVA prescribing information.

Last reviewed on RxList: 9/28/2011
This monograph has been modified to include the generic and brand name in many instances.