Efavirenz

12.1 Mechanism of Action Efavirenz is an antiviral drug [see Microbiology ( 12.4 )].

1 INDICATIONS & USAGE Efavirenz in combination with other antiretroviral agents is indicated for the treatment of human immunodeficiency virus type 1 (HIV-1) infection in adults and in pediatric patients at least 3 months old and weighing at least 3.5 kg. Efavirenz is a non-nucleoside reverse transcriptase inhibitor indicated in combination with other antiretroviral agents for the treatment of human immunodeficiency virus type 1 infection in adults and in pediatric patients at least 3 months old and weighing at least 3.5 kg.( 1 )

2 DOSAGE & ADMINISTRATION • Efavirenz should be taken orally once daily on an empty stomach, preferably at bedtime. ( 2 ) • Recommended adult dose: 600 mg. ( 2.2 ) • With rifampin, increase efavirenz dose to 800 mg once daily for patients weighing 50 kg or more. ( 2.2 ) • Pediatric dosing is based on weight. ( 2.3 ) 2.1 Hepatic Function Monitor hepatic function prior to and during treatment with efavirenz [ see Warnings and Precautions ( 5.9 ) ]. Efavirenz is not recommended in patients with moderate or severe hepatic impairment (Child Pugh B or C) [ see Warnings and Precautions ( 5.9 ) and Use in Specific Populations ( 8.6 ) ]. 2.2 Adults The recommended dosage of efavirenz is 600 mg orally, once daily, in combination with a protease inhibitor and/or nucleoside analogue reverse transcriptase inhibitors (NRTIs). It is recommended that efavirenz be taken on an empty stomach, preferably at bedtime. The increased efavirenz concentrations observed following administration of efavirenz with food may lead to an increase in frequency of adverse reactions [see Clinical Pharmacology ( 12.3 )]. Dosing at bedtime may improve the tolerability of nervous system symptoms [see Warnings and Precautions ( 5.6 ), Adverse Reactions ( 6.1 ), and Patient Counseling Information ( 17 )]. Efavirenz capsules or tablets should be swallowed intact with liquid. Concomitant Antiretroviral Therapy Efavirenz must be given in combination with other antiretroviral medications [see Indications and Usage ( 1 ), Warnings and Precautions ( 5.3) , Drug Interactions ( 7.1 ), and Clinical Pharmacology ( 12.3 )]. Dosage Adjustment If efavirenz is coadministered with voriconazole, the voriconazole maintenance dose should be increased to 400 mg every 12 hours and the efavirenz dose should be decreased to 300 mg once daily using the capsule formulation (one 200 mg and two 50 mg capsules or six 50 mg capsules). Efavirenz tablets must not be broken. [See Drug Interactions ( 7.1 , Table 5) and Clinical Pharmacology ( 12.3 , Tables 7 and 8] . If efavirenz is coadministered with rifampin to patients weighing 50 kg or more, an increase in the dose of efavirenz to 800 mg once daily is recommended [see Drug Interactions ( 7.1 , Table 5) and Clinical Pharmacology ( 12.3 , Table 8)]. 2.3 Pediatric Patients It is recommended that efavirenz be taken on an empty stomach, preferably at bedtime. Table 1 describes the recommended dose of efavirenz for pediatric patients 3 months of age or older and weighing between 3.5 kg and 40 kg [see Clinical Pharmacology ( 12.3 )] . The recommended dosage of efavirenz for pediatric patients weighing 40 kg or greater is 600 mg once daily. For pediatric patients who cannot swallow capsules, the capsule contents can be administered with a small amount of food or infant formula using the capsule sprinkle method of administration . Table 1: Efavirenz Dosing in Pediatric Patients Patient Body Weight Efavirenz Daily Dose Number of Capsules a or Tablets b and Strength to Administer 3.5 kg to less than 5 kg 100 mg two 50 mg capsules 5 kg to less than 7.5 kg 150 mg three 50 mg capsule 7.5 kg to less than 15 kg 200 mg one 200 mg capsule 15 kg to less than 20 kg 250 mg one 200 mg + one 50 mg capsule 20 kg to less than 25 kg 300 mg one 200 mg + two 50 mg capsules 25 kg to less than 32.5 kg 350 mg one 200 mg + three 50 mg capsules 32.5 kg to less than 40 kg 400 mg two 200 mg capsules at least 40 kg 600 mg one 600 mg tablet OR three 200 mg capsules a Capsules can be administered intact or as sprinkles [see Dosage and Administration (2.4)]. b Tablets must not be crushed

6 ADVERSE REACTIONS The most significant adverse reactions observed in patients treated with efavirenz are: •psychiatric symptoms [see Warnings and Precautions ( 5.5 )], •nervous system symptoms [see Warnings and Precautions ( 5.6 )], •rash [see Warnings and Precautions ( 5.8 )]. •hepatotoxicity [see Warnings and Precautions ( 5.9 )] Most common adverse reactions (>5%, moderate-severe) are impaired concentration, abnormal dreams, rash, dizziness, nausea, headache, fatigue, insomnia, and vomiting.( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Macleods Pharmaceutical Ltd at 1-888-943-3210 or 1-855-926-3384 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical studies are conducted under widely varying conditions, the adverse reaction rates reported cannot be directly compared to rates in other clinical studies and may not reflect the rates observed in clinical practice. Adverse Reactions in Adults. The most common (>5% in either efavirenz treatment group) adverse reactions of at least moderate severity among patients in Study 006 treated with efavirenz in combination with zidovudine/lamivudine or indinavir were rash, dizziness, nausea, headache, fatigue, insomnia, and vomiting Selected clinical adverse reactions of moderate or severe intensity observed in ≥2% of efavirenz-treated patients in two controlled clinical trials are presented in Table 2 Table 2: Selected Treatment-Emergent a Adverse Reactions of Moderate or Severe Intensity Reported in ≥2% of EFAVIRENZ TABLETS-Treated Patients in Studies 006 and ACTG 364 Study 006 LAM-, NNRTI-, and Protease Inhibitor-Naive Patients Study ACTG 364 NRTI-experienced, NNRTI- and Protease Inhibitor-Naive Patients Adverse Reactions Efavirenz b + ZDV/LAM (n=412) Efavirenz b + Indinavir (n=415) Indinavir + ZDV/LAM (n=401) Efavirenz b + Nelfinavir + NRTIs (n=64) Efavirenz b + NRTIs (n=65) Nelfinavir + NRTIs (n=66) 180 weeks c 102 weeks c 76 weeks c 71.1 weeks c 70.9 weeks c 62.7 weeks c Psychiatric Body as a Whole Fatigue 8% 5% 9% 0 2% 3% Pain 1% 2% 8% 13% 6% 17% Central and Peripheral Nervous System Dizziness 9% 9% 2% 2% 6% 6% Headache 8% 5% 3% 5% 2% 3% Insomnia 7% 7% 2% 0 0 2% Concentration impaired 5% 3% <1% 0 0 0 Abnormal dreams 3% 1% 0 — — — Somnolence 2% 2% <1% 0 0 0 Anorexia 1% <1% <1% 0 2% 2% Gastrointestinal Nausea 10% 6% 24% 3% 2% 2% Vomiting 6% 3% 14% — — — Diarrhea 3% 5% 6% 14% 3% 9% Dyspepsia 4% 4% 6% 0 0 2% Abdominal pain 2% 2% 5% 3% 3% 3% Anxiety 2% 4% <1% — — — Depression 5% 4% <1% 3% 0 5% Nervousness 2% 2% 0 2% 0 2% Skin & Appendages Rash d 11% 16% 5% 9% 5% 9% Pruritis <1% 1% 1% 9% 5% 9% a Includes adverse events at least possibly related to study drug or of unknown relationship for Study 006. Includes all adverse events regardless of relationship to study drug for Study ACTG 364. b Efavirenz tablets provided as 600 mg once daily. c Median duration of treatment. d Includes erythema multiforme, rash, rash erythematous, rash follicular, rash maculopapular, rash petechial, rash pustular, and urticaria for Study 006 and macules, papules, rash, erythema, redness, inflammation, allergic rash, urticaria, welts, hives, itchy, and pruritus for ACTG 364. — = Not Specified. ZDV = zidovudine, LAM=lamivudine. Pancreatitis has 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 patients treated with efavirenz 600 mg than in control patients ( see Laboratory Abnormalities ). Nervous System Symptoms For 1008 patients treated with regimens containing efavirenz and 635 patients treated with a control regimen in controlled trials, Table 3 lists the frequency of symptoms of different degrees of severity and gives the discontinuation rates for one or more of the following nervous system symptoms: dizziness, insomnia, impaired concentration, somnolence, abnormal dreaming, euphoria, confusion, agitation, amnesia, hallucinations, stupor, abnormal thinking, and depersonalization [see Warnings and Precautions ( 5.6 )]. The frequencies of specific central and peripheral nervous system symptoms are provided in Table 2 Table 3: Percent of Patients with One or More Selected Nervous System Symptoms a,b Percent of Patients with: EFAVIRENZ TABLETS 600 mg Once Daily (n=1008) Control Groups (n=635) % % Symptoms of any severity 52.7 24.6 Mild symptoms c 33.3 15.6 Moderate symptoms d 17.4 7.7 Severe symptoms e 2.0 1.3 Treatment discontinuation as a result of symptoms 2.1 1.1 a Includes events reported regardless of causality. b Data from Study 006 and three Phase 2/3 studies. c "Mild" = Symptoms which do not interfere with patient’s daily activities. d "Moderate" = Symptoms which may interfere with daily activities. e "Severe" = Events which interrupt patient’s usual daily activities. Psychiatric Symptoms Serious psychiatric adverse experiences have been reported in patients treated with efavirenz tablets. In contr

7 DRUG INTERACTIONS Coadministration of efavirenz can alter the concentrations of other drugs and other drugs may alter the concentrations of efavirenz. The potential for drug-drug interactions should be considered before and during therapy. ( 7 ) 7.1 Potential for efavirenz to Affect other Drugs Efavirenz has been shown in vivo to induce CYP3A and CYP2B6. Other compounds that are substrates of CYP3A or CYP2B6 may have decreased plasma concentrations when coadministered with efavirenz 7.2 Potential for Other Drugs to Affect efavirenz Drugs that induce CYP3A activity (e.g., phenobarbital, rifampin, rifabutin) would be expected to increase the clearance of efavirenz resulting in lowered plasma concentrations [see Dosage and Administration ( 2.2 )]. 7.3 QT Prolonging Drugs There is limited information available on the potential for a pharmacodynamic interaction between efavirenz and drugs that prolong the QTc interval. QTc prolongation has been observed with the use of efavirenz [see Clinical Pharmacology ( 12.2 )]. Consider alternatives to efavirenz when coadministered with a drug with a known risk of Torsade de Pointes. 7.4 Established and Other Potentially Significant Drug Interactions Drug interactions with efavirenz are summarized in Table 5. For pharmacokinetics data, [see Clinical Pharmacology ( 12.3 )] Tables 7 and 8. This table includes potentially significant interactions, but is not all inclusive Table 5: 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 HIV antiviral agents Protease inhibitor: Fosamprenavir calcium ↓ amprenavir Fosamprenavir (unboosted): Appropriate doses of the combinations 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 efavirenz tablets are administered with fosamprenavir/ritonavir once daily. No change in the ritonavir dose is required when efavirenz tablets are administered with fosamprenavir plus ritonavir twice daily. Protease inhibitor: Atazanavir ↓ atazanavir * Treatment –naïve patients : When co-administered with efavirenz tablets , the recommended dose of atazanavir is 400 mg with ritonavir 100 mg (together once daily with food) and efavirenz tablets 600 mg ( once daily on an empty stomach, preferably at bedtime). Treatment-experienced patients: Co-administration of efavirenz tablets and atazanavir is not recommended. Protease inhibitor: Indinavir ↓ indinavir * The optimal dose of indinavir, when given in combination with efavirenz tablets are 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 * Lopinavir/ritonavir once daily dosing is not recommended when co-administered with efavirenz. The dose of lopinavir/ritonavir must be increased when co-administered with efavirenz. See the lopinavir/ritonavir prescribing information for dose adjustments of lopinavir/ritonavir when co-administered with efavirenz in adult and pediatric patients. Protease inhibitor: Ritonavir ↑ ritonavir * ↑ efavirenz * Monitor for elevation of liver enzymes and for adverse clinical experiences (e.g., dizziness, nausea, paresthesia) when efavirenz is co-administered with ritonavir. Protease inhibitor: Saquinavir ↓ saquinavir * Appropriate doses of the combination of efavirenz and saquinavir/ritonavir with respect to safety and efficacy have not been established. NNRTI: Other NNRTIs ↑ or ↓ efavirenz and/ or NNRTI Combining two NNRTIs has not been shown to be beneficial. efavirenz should not be coadministered with other NNRTIs. CCR5 co-receptor antagonist: Maraviroc ↓ maraviroc* Refer to the full prescribing information for maraviroc for guidance on co-administration with efavirenz. Hepatitis C antiviral agents Boceprevir ↓ boceprevir* Concomitant administration of boceprevir with efavirenz is not recommended because it may result in loss of therapeutic effect of boceprevir Elbasvir/Grazoprevir ↓ elbasvir ↓ grazoprevir Co-administration o efavirenz with elbasvir/grazoprevir is contraindicated [see Contraindications ( 4 )] because it may lead to loss of virologic response to elbasvir/grazoprevir. Pibrentasvir/Glecaprevir ↓ pibrentasvir Co-administration of efavirenz is not recommended because it may lead to reduced therapeutic effect of pibrentasvir/glecaprevir Simeprevir ↓simeprevir* ↔efavirenz* Concomitant administration of simeprevir with efavirenz is not recommended because it may result in loss oftherapeutic effect of simeprevir. Velpatasvir/ Sofosbuvir ↓ velpatasvir Co-administration of efavirenz and sofosbuvir/velpatasvir is not recommended because it may result in loss of therapeutic effect of sofosbuvir/velpatasvir Velpatasvir /Sofosbuvir/Voxilaprevir ↓ velpatasv