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Elvitegravir, Cobicistat, Emtricitabine, and Tenofovir Alafenamide

Class: HIV Integrase Inhibitors
Chemical Name: 6 - [(3 - Chloro - 2 - fluorophenyl)methyl] - 1,4 - dihydro - 1 - [(1S) - 1 - (hydroxymethyl) - 2 - methylpropyl] - 7 - methoxy - 4 - oxo - 3 - quinolinecarboxylic acid
Molecular Formula: C23H23ClFNO5C40H53N7O5S2C8H10FN3O3SC23H31O7N6P
CAS Number: 697761-98-1
Brands: Genvoya

Warning(s)

  • Lactic Acidosis and Hepatomegaly with Steatosis
  • Lactic acidosis and severe hepatomegaly with steatosis, including fatalities, reported in patients receiving HIV nucleoside reverse transcriptase inhibitors (NRTIs) in conjunction with other antiretrovirals.1 218 221 (See Lactic Acidosis and Severe Hepatomegaly with Steatosis under Cautions.)

  • HBV Infection
  • Fixed combination of EVG/c/FTC/TAF not indicated for treatment of chronic HBV infection.1 Safety and efficacy of EVG/c/FTC/TAF not established in HIV-1-infected patients coinfected with HBV.1

  • Severe, acute exacerbations of HBV reported following discontinuance of preparations containing emtricitabine and/or the tenofovir prodrug tenofovir disoproxil fumarate (tenofovir DF; TDF) in patients coinfected with HIV and HBV;1 218 221 may occur with EVG/c/FTC/TAF.1 Monitor hepatic function closely with both clinical and laboratory follow-up for at least several months after EVG/c/FTC/TAF discontinued in patients coinfected with HIV and HBV.1 If appropriate, initiation of HBV treatment may be warranted.1 (See HIV-infected Individuals Coinfected with HBV under Cautions.)

Introduction

Antiretroviral; fixed combination of elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide (EVG/c/FTC/TAF).1 200 Elvitegravir (EVG) is an HIV integrase strand transfer inhibitor (INSTI) antiretroviral; cobicistat is a CYP3A inhibitor used as a pharmacokinetic enhancer to decrease metabolism and increase plasma concentrations of EVG; emtricitabine (FTC) and tenofovir alafenamide (TAF) are HIV nucleoside reverse transcriptase inhibitors (NRTIs).1 200

Uses for Elvitegravir, Cobicistat, Emtricitabine, and Tenofovir Alafenamide

Treatment of HIV Infection

Treatment of HIV-1 infection in antiretroviral-naive (have not previously received antiretroviral therapy) or antiretroviral-experienced (previously treated) adults and adolescents ≥12 years of age.1 2 3 4 5 200 201

Fixed combination of EVG/c/FTC/TAF used alone as a complete regimen for treatment of HIV-1 infection;1 200 do not use with other antiretrovirals.1 200

For initial treatment in antiretroviral-naive adults, experts state EVG/c/FTC/TAF is a recommended INSTI-based regimen, but use only in patients with baseline estimated Clcr ≥30 mL/minute.200

For initial treatment in HIV-infected children and adolescents, experts state that EVG/c/FTC/TAF is a preferred HIV INSTI-based regimen in adolescents ≥12 years of age weighing ≥35 kg, including adolescents in early puberty (sexual maturity rating [SMR] 1–3), but use only in patients with baseline estimated Clcr ≥30 mL/minute.201

For antiretroviral-experienced adults, manufacturer states EVG/c/FTC/TAF can be used to replace the current antiretroviral regimen in those with plasma HIV-1 RNA levels <50 copies/mL on a stable antiretroviral regimen for ≥6 months who have no history of treatment failure and are infected with HIV-1 with no known substitutions associated with resistance to the antiretroviral components of the fixed combination (i.e., elvitegravir, emtricitabine, tenofovir).1

Elvitegravir, Cobicistat, Emtricitabine, and Tenofovir Alafenamide Dosage and Administration

General

  • Determine estimated Clcr, urine glucose, and urine protein prior to initiation of EVG/c/FTC/TAF and routinely monitor during treatment in all patients;1 in addition, monitor serum phosphorus in those with chronic kidney disease.1 (See Renal Impairment under Cautions.)

  • Test for HBV infection prior to initiation of EVG/c/FTC/TAF.1 (See HIV-infected Individuals Coinfected with HBV under Cautions.)

Administration

Oral Administration

Administer fixed combination of EVG/c/FTC/TAF orally once daily with food.1

Dosage

Each fixed-combination tablet of EVG/c/FTC/TAF contains elvitegravir 150 mg, cobicistat 150 mg, emtricitabine 200 mg, and tenofovir alafenamide 10 mg.1

Tenofovir alafenamide component provided as tenofovir alafenamide fumarate; dosage expressed in terms of tenofovir alafenamide.1

Pediatric Patients

Treatment of HIV Infection
Oral

Pediatric patients ≥12 years of age weighing ≥35 kg: 1 tablet of EVG/c/FTC/TAF (elvitegravir 150 mg, cobicistat 150 mg, emtricitabine 200 mg, tenofovir alafenamide 10 mg) once daily.1

Adults

Treatment of HIV Infection
Oral

1 tablet of EVG/c/FTC/TAF (elvitegravir 150 mg, cobicistat 150 mg, emtricitabine 200 mg, tenofovir alafenamide 10 mg) once daily.1

Special Populations

Hepatic Impairment

Mild or moderate hepatic impairment (Child-Pugh class A or B): Dosage adjustments not needed.1

Severe hepatic impairment (Child-Pugh class C): Do not use.1 (See Hepatic Impairment under Cautions.)

Renal Impairment

Estimated Clcr ≥30 mL/minute: Dosage adjustments not needed.1

Estimated Clcr <30 mL/minute: Do not use.1 (See Renal Impairment under Cautions.)

Cautions for Elvitegravir, Cobicistat, Emtricitabine, and Tenofovir Alafenamide

Contraindications

  • Concomitant use with drugs highly dependent on CYP3A for metabolism and for which elevated plasma concentrations are associated with serious and/or life-threatening events (e.g., alfuzosin, cisapride, ergot alkaloids, lovastatin, oral midazolam, pimozide, sildenafil used for treatment of pulmonary arterial hypertension [PAH], simvastatin, triazolam).1 (See Specific Drugs under Interactions.)

  • Concomitant use with drugs that are potent inducers of CYP3A; these drugs may result in decreased elvitegravir and/or cobicistat concentrations resulting in possible decreased antiretroviral efficacy and development of resistance.1 (See Specific Drugs under Interactions.)

Warnings/Precautions

Warnings

Lactic Acidosis and Severe Hepatomegaly with Steatosis

Lactic acidosis and severe hepatomegaly with steatosis (sometimes fatal) reported in patients receiving NRTIs, including emtricitabine and tenofovir DF, in conjunction with other antiretrovirals.1 218 221 Reported mostly in women;1 218 221 obesity and long-term NRTI therapy also may be risk factors.1 218 221 Has been reported in patients with no known risk factors.1 218 221

Use NRTIs with caution in patients with known risk factors for liver disease.1 218 221

Interrupt EVG/c/FTC/TAF treatment if there are clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity (e.g., hepatomegaly and steatosis even in the absence of marked increases in serum aminotransferase concentrations).1

HIV-infected Individuals Coinfected with HBV

Test all HIV-infected patients for presence of HBV before initiating antiretroviral therapy.1 200

EVG/c/FTC/TAF not indicated for treatment of chronic HBV infection.1 Safety and efficacy of EVG/c/FTC/TAF not established in patients coinfected with HIV and HBV.1

Severe acute exacerbations of HBV reported following discontinuance of preparations containing emtricitabine and/or tenofovir DF in HIV-infected patients with HBV infection.1 218 221 HBV exacerbations have been associated with hepatic decompensation and hepatic failure.1 218 Such reactions could occur with EVG/c/FTC/TAF.1

Closely monitor hepatic function (using both clinical and laboratory follow-up) for at least several months after EVG/c/FTC/TAF is discontinued in patients coinfected with HIV and HBV.1 If appropriate, initiation of HBV treatment may be warranted.1

Other Warnings/Precautions

Renal Toxicity

Renal impairment, including acute renal failure and Fanconi syndrome (renal tubular injury with hypophosphatemia), reported with tenofovir prodrugs (e.g., tenofovir DF).1 221

Cobicistat (a component of EVG/c/FTC/TAF) may cause modest increase in Scr and modest decrease in estimated Clcr due to inhibition of tubular secretion of creatinine;1 15 glomerular function not affected.1 15

Determine estimated Clcr, urine glucose, and urine protein prior to and routinely monitor during EVG/c/FTC/TAF treatment in all patients.1 In addition, monitor serum phosphorus in those with chronic kidney disease.1 (See Renal Impairment under Cautions.)

Do not use EVG/c/FTC/TAF in patients with estimated Clcr <30 mL/minute.1

If a confirmed increase in Scr of >0.4 mg/dL from baseline occurs during EVG/c/FTC/TAF treatment, closely monitor for renal toxicity.1 Discontinue EVG/c/FTC/TAF if clinically important decreases in renal function occur or there is evidence of Fanconi syndrome.1

Because persistent or worsening bone pain, pain in extremities, fractures, and/or muscular pain or weakness may be manifestations of proximal renal tubulopathy, promptly evaluate renal function in patients at risk for renal dysfunction who present with such symptoms.1 221 (See Bone Effects under Cautions.)

Patients receiving a tenofovir prodrug who have impaired renal function or are taking nephrotoxic agent (e.g., high-dose or multiple NSAIAs) are at increased risk of developing adverse renal effects.1 (See Interactions.)

Bone Effects

Decreases in bone mineral density (BMD) and increases in biochemical markers of bone metabolism, suggestive of increased bone turnover, reported with tenofovir prodrugs (tenofovir alafenamide, tenofovir DF).1 221 In clinical trials in HIV-1-infected treatment-naive adults, substantial decline in BMD reported in 15% of patients receiving EVG/c/FTC/TAF.1 Long-term clinical importance of these changes unknown.1 221

Osteomalacia associated with proximal renal tubulopathy, which manifested as bone pain or pain in extremities and may contribute to fractures, reported in patients receiving preparations containing tenofovir DF.1 221 Hypophosphatemia and osteomalacia secondary to proximal renal tubulopathy also reported in patients at risk for renal dysfunction who presented with persistent or worsening bone or muscle symptoms while receiving preparations containing tenofovir DF.1 Although not observed in clinical studies of EVG/c/FTC/TAF,1 risk of osteomalacia in patients receiving the fixed combination unknown.1

Consider BMD monitoring in adults and pediatric patients receiving EVG/c/FTC/TAF who have a history of pathologic bone fracture or other risk factors for osteoporosis or bone loss.1 Calcium and vitamin D supplementation may be beneficial for all patients.1 If bone abnormalities suspected, obtain appropriate consultation.1

Interactions

Concomitant use with certain drugs may result in clinically important interactions, including some that may decrease antiretroviral plasma concentrations leading to loss of therapeutic effect and possible development of resistance and some that may increase plasma concentrations of the antiretroviral agents and/or concomitant drugs leading to clinically important adverse reactions.1 (See Contraindications and see Interactions.)

Consider potential drug interactions prior to and during therapy.1 Review drugs used concomitantly with EVG/c/FTC/TAF;1 monitor patient for adverse reactions associated with these drugs.1 (See Interactions.)

Use of Fixed Combinations

Consider cautions, precautions, and contraindications associated with each component of EVG/c/FTC/TAF.1 218 Consider cautionary information applicable to specific populations (e.g., pregnant or nursing women, individuals with hepatic or renal impairment, geriatric patients) for each drug in the fixed combination.1 218

EVG/c/FTC/TAF is used alone as a complete regimen for treatment of HIV-1 infection;1 200 do not use in conjunction with other antiretrovirals.1 200 (See Specific Drugs under Interactions.)

Do not use EVG/c/FTC/TAF concomitantly with any preparation that contains any of its components (elvitegravir, cobicistat, emtricitabine, tenofovir alafenamide).1 In addition, do not use EVG/c/FTC/TAF concomitantly with any preparation containing tenofovir DF, lamivudine, adefovir dipivoxil, or ritonavir.1

Adipogenic Effects

Possible redistribution or accumulation of body fat, including central obesity, dorsocervical fat enlargement (“buffalo hump”), peripheral wasting, facial wasting, breast enlargement, and general cushingoid appearance.1

Mechanism and long-term consequences of fat redistribution unknown;1 causal relationship not established.1

Immune Reconstitution Syndrome

During initial treatment, patients who respond to antiretroviral therapy may develop an inflammatory response to indolent or residual opportunistic infections (e.g., Mycobacterium avium complex [MAC], M. tuberculosis, cytomegalovirus [CMV], Pneumocystis jirovecii [formerly P. carinii]);1 this may necessitate further evaluation and treatment.1

Autoimmune disorders (e.g., Graves' disease, polymyositis, Guillain-Barré syndrome) also reported in the setting of immune reconstitution;1 time to onset is more variable and can occur many months after initiation of antiretroviral therapy.1

Specific Populations

Pregnancy

Category B.1

Antiretroviral Pregnancy Registry at 800-258-4263 or .1 202

Lactation

Elvitegravir, cobicistat, and tenofovir are distributed into milk in rats;1 not known whether these drugs distributed into human milk.1 Emtricitabine is distributed into human milk.1

Instruct HIV-infected women not to breast-feed because of risk of HIV transmission and risk of adverse effects in the infant.1 202

Pediatric Use

Safety and efficacy of EVG/c/FTC/TAF not established in pediatric patients <12 years of age.1

Experts state that EVG/c/FTC/TAF is a preferred INSTI-based regimen in adolescents ≥12 years of age weighing ≥35 kg, including those in early puberty (SMR 1–3).201

Clinical trial data indicate safety and efficacy of EVG/c/FTC/TAF in HIV-1-infected, treatment-naive pediatric patients 12 to <18 years of age is similar to that reported in adults.1

Geriatric Use

No differences in safety or efficacy of EVG/c/FTC/TAF observed between individuals ≥65 years of age and individuals 12 to <65 years of age.1

Hepatic Impairment

Mild hepatic impairment (Child-Pugh class A): No clinically important effects on pharmacokinetics of tenofovir alafenamide.1

Moderate hepatic impairment (Child-Pugh class B): No clinically important effects on pharmacokinetics of elvitegravir, cobicistat, or tenofovir alafenamide;1 not expected to affect pharmacokinetics of emtricitabine.1

Severe hepatic impairment (Child-Pugh class C): EVG/c/FTC/TAF not recommended;1 data not available to date regarding pharmacokinetics or safety in such patients.1

Renal Impairment

Determine estimated Clcr, urine glucose, and urine protein prior to and routinely monitor during EVG/c/FTC/TAF treatment in all patients.1 Also monitor serum phosphorus in those with chronic kidney disease since such patients are at greater risk of developing Fanconi syndrome while receiving tenofovir prodrugs.1

Estimated Clcr <30 mL/minute: Do not use EVG/c/FTC/TAF;1 safety not established.1

Common Adverse Effects

Nausea, diarrhea, fatigue, headache.1

Interactions for Elvitegravir, Cobicistat, Emtricitabine, and Tenofovir Alafenamide

Elvitegravir: Substrate of CYP3A;1 24 25 weak inducer and weak inhibitor of CYP3A.24 25 Induces CYP2C9.1 Does not inhibit CYP1A, 2A6, 2C9, 2C19, 2D6, or 2E1.24 Inhibits organic anion transport polypeptides (OATP)1B1 and 1B3.1 24

Cobicistat: Substrate and inhibitor of CYP3A and 2D6.1 24 25 Inhibits p-glycoprotein (P-gp) transport, breast cancer resistance protein (BCRP), and OATP1B1 and 1B3.1

Emtricitabine: Not a substrate of CYP enzymes;218 does not inhibit CYP1A2, 2A6, 2B6, 2C9, 2C19, 2D6, or 3A4.218

Tenofovir alafenamide: Weak inhibitor of CYP3A;1 25 does not induce or inhibit CYP1A2, 2B6, 2C8, 2C9, 2C19, or 2D6.1 25 Substrate of P-gp, BCRP, and OATP1B1 and 1B3.1 25

The following interactions are based on studies using elvitegravir, elvitegravir administered with cobicistat (cobicistat-boosted elvitegravir), elvitegravir administered with low-dose ritonavir (ritonavir-boosted elvitegravir), cobicistat, or EVG/c/FTC/TAF or are predicted to occur.1

Consider potential interactions associated with each drug in the fixed combination.1

Drugs Affecting or Metabolized by Hepatic Microsomal Enzymes

CYP3A or 2D6 substrates: Potential increased plasma concentrations of such substrates.1

CYP3A inducers: Potential decreased plasma concentrations of elvitegravir, cobicistat, and/or tenofovir alafenamide;1 possible decreased antiretroviral efficacy and development of resistance.1

CYP3A inhibitors: Potential increased plasma concentrations of cobicistat.1

Drugs Affected by P-glycoprotein Transport

P-gp substrates: Potential increased concentrations of such substrates.1

P-gp inhibitors: Potential increased tenofovir alafenamide concentrations.1 Cobicistat (a P-gp inhibitor) increases tenofovir alafenamide plasma concentrations when the drugs administered as EVG/c/FTC/TAF;1 further increases not expected if an additional P-gp inhibitor used with EVG/c/FTC/TAF.1

P-gp inducers: Decreased absorption and decreased plasma concentrations of tenofovir alafenamide expected.1

Drugs Affected by Breast Cancer Resistance Protein

BCRP substrates: Potential increased concentrations of such substrates.1

BCRP inhibitors: Potential increased tenofovir alafenamide concentrations.1 Cobicistat (a BCRP inhibitor) increases tenofovir alafenamide plasma concentrations when the drugs administered as EVG/c/FTC/TAF;1 further increases not expected if an additional BCRP inhibitor used with EVG/c/FTC/TAF.1

Drugs Affected by Organic Anion Transport Polypeptides

OATP1B1 or 1B3 substrates: Potential increased concentrations of such substrates.1

Drugs Affecting Renal Function

Drugs that reduce renal function or compete for active tubular secretion: Potential increased concentrations of emtricitabine, tenofovir, and/or concomitant drug.1

Specific Drugs

Drug

Interaction

Comments

Alfuzosin

Possible increased alfuzosin concentrations;1 may result in hypotension1

Concomitant use contraindicated1

Aminoglycosides (e.g., gentamicin)

Competition for active tubular secretion may increase concentrations of emtricitabine, tenofovir, and/or the aminoglycoside;1 may increase risk of adverse effects1

Antacids, aluminum- or magnesium-containing

Decreased elvitegravir concentrations and AUC when administered simultaneously1

Give antacids at least 2 hours before or after EVG/c/FTC/TAF1

Antiarrhythmic agents (e.g., amiodarone, disopyramide, flecainide, lidocaine [systemic], mexiletine, propafenone, quinidine)

Amiodarone, disopyramide, flecainide, lidocaine (systemic), mexiletine, propafenone, quinidine: Possible increased antiarrhythmic agent concentrations1

Amiodarone, disopyramide, flecainide, lidocaine (systemic), mexiletine, propafenone, quinidine: Use concomitantly with caution;1 monitor antiarrhythmic agent concentrations if possible1

Anticonvulsants (carbamazepine, ethosuximide, oxcarbazepine, phenobarbital, phenytoin)

Carbamazepine, phenobarbital, phenytoin: Possible decreased elvitegravir, cobicistat, and tenofovir alafenamide concentrations with possible decreased antiretroviral efficacy and development of resistance1

Ethosuximide: Possible increased ethosuximide concentrations;1 possible decreased elvitegravir, cobicistat, and tenofovir alafenamide concentrations1

Oxcarbazepine: Possible decreased elvitegravir, cobicistat, and tenofovir alafenamide concentrations1

Carbamazepine, phenobarbital, phenytoin: Concomitant use contraindicated1

Ethosuximide: Clinical monitoring recommended1

Oxcarbazepine: Consider alternative anticonvulsant1

Antidepressants, tricyclics (amitriptyline, desipramine, imipramine, nortriptyline)

Possible increased tricyclic antidepressant concentrations and AUC1

Desipramine: Increased desipramine concentrations when used concomitantly with cobicistat1

Carefully titrate tricyclic antidepressant dosage and monitor clinical response1

Antifungals, azoles

Itraconazole: Possible increased itraconazole, elvitegravir, and cobicistat concentrations1

Ketoconazole: Increased ketoconazole, elvitegravir, and cobicistat concentrations1

Voriconazole: Possible increased voriconazole, elvitegravir, and cobicistat concentrations1

Itraconazole: Do not exceed itraconazole dosage of 200 mg daily1

Ketoconazole: Do not exceed ketoconazole dosage of 200 mg daily1

Voriconazole: Avoid concomitant use unless benefits outweigh risks1

Antimycobacterials (rifabutin, rifampin, rifapentine)

Rifabutin: Decreased elvitegravir concentrations and AUC and increased rifabutin metabolite concentrations and AUC when used with cobicistat-boosted elvitegravir;1 possible decreased tenofovir alafenamide concentrations;1 possible decreased antiretroviral efficacy and development of resistance1

Rifampin: Possible decreased elvitegravir, cobicistat, and tenofovir alafenamide concentrations with possible decreased antiretroviral efficacy and development of resistance1

Rifapentine: Possible decreased elvitegravir, cobicistat, and tenofovir alafenamide concentrations with possible decreased antiretroviral efficacy and development of resistance1

Rifabutin: Concomitant use not recommended1

Rifampin: Concomitant use contraindicated1

Rifapentine: Concomitant use not recommended1

Antipsychotics (e.g., perphenazine, pimozide, quetiapine, risperidone, thioridazine)

Perphenazine, risperidone, thioridazine: Possible increased antipsychotic concentrations1

Pimozide: Possible increased pimozide concentrations resulting in serious and/or life-threatening reactions (e.g., cardiac arrhythmias)1

Quetiapine: Increased quetiapine concentrations expected1

Perphenazine, risperidone, thioridazine: Decreased antipsychotic dosage may be needed1

Pimozide: Concomitant use contraindicated1

Quetiapine: Consider alternative antiretroviral;1 if EVG/c/FTC/TAF necessary in patient receiving stable quetiapine dosage, reduce quetiapine dosage to one-sixth of original dosage and monitor for quetiapine-associated adverse effects1

β-Adrenergic blocking agents (metoprolol, timolol)

Metoprolol, timolol: Possible increased β-blocking agent concentrations1

Metoprolol, timolol: Monitor clinically;1 reduced β-blocker dosage may be needed1

Benzodiazepines (e.g., clorazepate, diazepam, estazolam, flurazepam, lorazepam, midazolam, triazolam)

Diazepam: Possible increased diazepam concentrations1

Lorazepam: Clinically important effects on lorazepam concentrations not expected1

Midazolam or triazolam: Increased benzodiazepine concentrations;1 potential for serious and/or life-threatening adverse effects (e.g., prolonged or increased sedation or respiratory depression)1

Clorazepate, estazolam, flurazepam: Possible increased benzodiazepine concentrations1

Diazepam: Use concomitantly only in monitored setting where respiratory depression and/or prolonged sedation can be managed1

Oral midazolam or triazolam: Concomitant use contraindicated1

Parenteral midazolam: Use concomitantly only in monitored setting where respiratory depression and/or prolonged sedation can be managed;1 consider reduced midazolam dosage, particularly if >1 dose will be used1

Bosentan

Possible increased bosentan concentrations1

In patient already receiving EVG/c/FTC/TAF for ≥10 days, initiate bosentan using dosage of 62.5 mg once daily or every other day based on individual tolerability1

In patient already receiving bosentan, discontinue bosentan for at least 36 hours prior to initiating EVG/c/FTC/TAF;1 after ≥10 days of EVG/c/FTC/TAF, resume bosentan using dosage of 62.5 mg once daily or every other day based on individual tolerability1

Buprenorphine/naloxone

Increased buprenorphine and norbuprenorphine concentrations and AUCs;1 decreased naloxone concentrations and AUC1

Monitor closely for sedation and adverse cognitive effects;1 dosage adjustments not needed1

Bupropion

Possible increased bupropion concentrations1

Carefully titrate antidepressant dosage based on clinical response1

Buspirone

Possible increased buspirone concentrations1

Monitor clinically;1 reduced buspirone dosage may be needed1

Calcium-channel blocking agents (amlodipine, diltiazem, felodipine, nicardipine, nifedipine, verapamil)

Possible increased calcium-channel blocking agent concentrations1

Use concomitantly with caution1 ; monitor clinically1

Cisapride

Possible increased cisapride concentrations;1 potential for serious and/or life-threatening reactions (e.g., cardiac arrhythmias)1

Concomitant use contraindicated1

Cobicistat

Increased elvitegravir concentrations and AUC as the result of cobicistat inhibition of CYP3A;1 acts as a pharmacokinetic enhancer (cobicistat-boosted elvitegravir);1 used to therapeutic advantage in fixed-combination EVG/c/FTC/TAF1

Increased tenofovir alafenamide concentrations and AUC as the result of cobicistat inhibition of P-gp, BCRP, and OATP1B1 and 1B31 25

Does not antagonize antiretroviral effects of elvitegravir, tenofovir, or emtricitabine1

Component of fixed-combination EVG/c/FTC/TAF1

Colchicine

Increased colchicine concentrations expected1

Patients with renal or hepatic impairment: Concomitant use not recommended1

Colchicine for treatment of gout flares: In those receiving EVG/c/FTC/TAF, use initial colchicine dose of 0.6 mg followed by 0.3 mg 1 hour later and repeat dose no earlier than 3 days later1

Colchicine for prophylaxis of gout flares: In those receiving EVG/c/FTC/TAF, decrease colchicine dosage to 0.3 mg once daily in those originally receiving 0.6 mg twice daily or decrease dosage to 0.3 mg once every other day in those originally receiving 0.6 mg once daily1

Colchicine for treatment of familial Mediterranean fever (FMF): In those receiving EVG/c/FTC/TAF, use maximum colchicine dosage of 0.6 mg daily (may be given as 0.3 mg twice daily)1

Corticosteroids (dexamethasone, fluticasone)

Dexamethasone (systemic): Possible decreased elvitegravir and cobicistat concentrations1

Fluticasone (orally inhaled, intranasal): Possible increased fluticasone concentrations1

Dexamethasone (systemic): Consider alternative corticosteroid1

Fluticasone (orally inhaled, intranasal): Consider alternative corticosteroid, particularly for long-term use1

Digoxin

Increased digoxin concentrations1

Use concomitantly with caution; monitor digoxin concentrations1

Elbasvir and grazoprevir

Fixed combination of elbasvir and grazoprevir (elbasvir/grazoprevir): Possible increased elbasvir and grazoprevir concentrations177

Elbasvir/grazoprevir: Concomitant use not recommended177

Ergot alkaloids (dihydroergotamine, ergotamine, methylergonovine)

Potential for serious and/or life-threatening adverse effects (e.g., peripheral vasospasm, ischemia of extremities)1

Concomitant use contraindicated1

Estrogens/progestins

Oral contraceptives containing ethinyl estradiol and norgestimate: Decreased ethinyl estradiol concentrations and AUC and increased norgestimate concentrations and AUC;1 possible effects of increased norgestimate unknown but may include increased risk of insulin resistance, dyslipidemia, acne, venous thrombosis1

Oral contraceptives containing progestin other than norgestimate: Not studied1

Other hormonal contraceptives (e.g., transdermal systems, vaginal ring, injections): Not studied1

Oral contraceptives containing ethinyl estradiol and norgestimate: Consider risks/benefits of concomitant use, particularly in women at risk of norgestimate-associated adverse effects1

Oral contraceptives containing progestins other than norgestimate: Consider alternative nonhormonal methods of contraception1

Other hormonal contraceptives (e.g., transdermal systems, vaginal ring, injections): Consider alternative nonhormonal methods of contraception1

Histamine H2-receptor antagonists (e.g., famotidine)

Famotidine: No clinically important effect on elvitegravir concentrations or AUC1

Histamine H2-receptor antagonists: Clinically important interactions with EVG/c/FTC/TAF not expected1

HIV integrase inhibitors (INSTIs)

Elvitegravir: Component of fixed-combination EVG/c/FTC/TAF; do not use concomitantly1

HIV nucleoside and nucleotide reverse transcriptase inhibitor antiretrovirals (NRTIs)

Emtricitabine, tenofovir alafenamide: Components of EVG/c/FTC/TAF;1 do not use any preparation containing emtricitabine or tenofovir alafenamide concomitantly with EVG/c/FTC/TAF1

Tenofovir DF: Do not use any preparation containing tenofovir DF concomitantly with EVG/c/FTC/TAF1

Other NRTIs (including lamivudine): Do not use concomitantly with EVG/c/FTC/TAF1

HIV protease inhibitors (PIs) (ritonavir)

Ritonavir: Do not use ritonavir or any ritonavir-containing preparation concomitantly with EVG/c/FTC/TAF1

HMG-CoA reductase inhibitors (statins)

Atorvastatin: Possible increased atorvastatin concentrations1

Lovastatin, simvastatin: Possible increased statin concentrations may lead to serious adverse effects, including myopathy and rhabdomyolysis1

Rosuvastatin: Increased rosuvastatin concentrations and AUC;1 no clinically important effect on elvitegravir pharmacokinetics1

Atorvastatin: Initiate using lowest atorvastatin dosage and titrate carefully; monitor for atorvastatin-associated adverse effects1

Lovastatin, simvastatin: Concomitant use contraindicated1

Immunosuppressive agents (cyclosporine, sirolimus, tacrolimus)

Cyclosporine: Possible increased cyclosporine, elvitegravir, and cobicistat concentrations1

Sirolimus, tacrolimus: Possible increased immunosuppressive agent concentrations1

Cyclosporine: Monitor cyclosporine concentrations;1 monitor for EVG/c/FTC/TAF-associated adverse effects1

Sirolimus, tacrolimus: Monitor immunosuppressive agent concentrations1

Ledipasvir

Fixed combination of ledipasvir and sofosbuvir (ledipasvir/sofosbuvir): Increased ledipasvir and sofosbuvir concentrations and AUCs and increased elvitegravir concentrations when used concomitantly with cobicistat-boosted elvitegravir1

Ledipasvir/sofosbuvir: Clinically important pharmacokinetic interactions with EVG/c/FTC/TAF not expected1

Macrolides (clarithromycin)

Clarithromycin: Possible increased macrolide and/or cobicistat concentrations1

Clarithromycin: Dosage modification not needed in patients with Clcr ≥60 mL/minute;1 reduce clarithromycin dosage by 50% in those with Clcr 50–60 mL/minute1

Methadone

Clinically important pharmacokinetic interactions not expected1

NSAIAs

High-dose or multiple NSAIAs: Competition for active tubular secretion may increase concentrations of emtricitabine, tenofovir, and/or the concomitant NSAIA;1 may increase risk of adverse effects1

Avoid EVG/c/FTC/TAF in patients who are receiving or have recently received a nephrotoxic drug (e.g., high-dose or multiple NSAIAs)1

Nucleoside and nucleotide antivirals (acyclovir, adefovir, cidofovir, entecavir, famciclovir, ganciclovir, ribavirin, valacyclovir, valganciclovir)

Acyclovir, cidofovir, ganciclovir, valacyclovir, valganciclovir: Competition for active tubular secretion may increase concentrations of emtricitabine, tenofovir, and/or the concomitant antiviral;1 may increase risk of adverse effects1

Entecavir, famciclovir: Clinically important interaction not expected1

Ribavirin: Clinically important interaction not expected1

Adefovir: Do not use concomitantly with EVG/c/FTC/TAF1

Proton-pump inhibitors (e.g., omeprazole)

Omeprazole: No clinically important effect on elvitegravir concentrations or AUC1

Proton-pump inhibitors: Clinically important interactions with EVG/c/FTC/TAF not expected1

Salmeterol

Possible increased salmeterol concentrations;1 may increase risk of QT prolongation, palpitations, or sinus tachycardia1

Concomitant use with EVG/c/FTC/TAF not recommended1

Selective serotonin-reuptake inhibitors (SSRIs)

SSRIs: Possible increased SSRI concentrations1

Sertraline: Clinically important interactions not expected1

SSRIs: Carefully titrate SSRI dosage and monitor antidepressant response1

Sildenafil

Increased sildenafil concentrations and increased risk of sildenafil-associated adverse effects (e.g., hypotension, syncope, visual disturbances, prolonged erection)1

Sildenafil for treatment of PAH: Concomitant use with EVG/c/FTC/TAF contraindicated1

Sildenafil for treatment of erectile dysfunction: Do not exceed sildenafil dosage of 25 mg once every 48 hours;1 closely monitor for sildenafil-related adverse effects1

Sofosbuvir

Clinically important pharmacokinetic interactions not expected1

St. John’s wort (Hypericum perforatum)

Possible decreased elvitegravir, cobicistat, and tenofovir alafenamide concentrations with possible decreased antiretroviral efficacy and development of resistance1

Concomitant use contraindicated1

Tadalafil

Increased tadalafil concentrations and increased risk of tadalafil-associated adverse effects (e.g., hypotension, syncope, visual disturbances, prolonged erection)1

Tadalafil for treatment of PAH in patients who have been receiving EVG/c/FTC/TAF for ≥1 week: Use initial tadalafil dosage of 20 mg once daily;1 if tolerated, increase dosage to 40 mg once daily1

EVG/c/FTC/TAF in patients receiving tadalafil for PAH: Discontinue tadalafil for at least 24 hours prior to initiating EVG/c/FTC/TAF;1 after ≥1 week of the antiretroviral agent, may resume tadalafil at a dosage of 20 mg once daily, and, if tolerated, may increase dosage to 40 mg once daily1

Tadalafil for treatment of erectile dysfunction: Do not exceed tadalafil dosage of 10 mg once every 72 hours;1 closely monitor for tadalafil-related adverse effects1

Trazodone

Possible increased trazodone concentrations1

Carefully titrate trazodone dosage and monitor antidepressant response1

Vardenafil

Possible increased vardenafil concentrations and increased risk of vardenafil-associated adverse effects (e.g., hypotension, syncope, visual disturbances, prolonged erection)1

Vardenafil for treatment of erectile dysfunction: Do not exceed vardenafil dosage of 2.5 mg once every 72 hours;1 closely monitor for vardenafil-related adverse effects1

Warfarin

Effect on warfarin pharmacokinetics not known1

Monitor INR1

Zolpidem

Possible increased zolpidem concentrations1

Monitor clinically;1 reduced zolpidem dosage may be needed1

Elvitegravir, Cobicistat, Emtricitabine, and Tenofovir Alafenamide Pharmacokinetics

Absorption

Bioavailability

Following an oral dose of EVG/c/FTC/TAF with food, peak plasma concentrations of elvitegravir and cobicistat occur at 4 and 3 hours, respectively, and peak plasma concentrations of emtricitabine and tenofovir occur at 3 and 1 hours, respectively.1

Cobicistat component of EVG/c/FTC/TAF increases plasma concentrations of elvitegravir and tenofovir alafenamide.1 25 (See Specific Drugs under Interactions.)

Food

Relative to fasting, administration of EVG/c/FTC/TAF with high-fat meal (approximately 800 kcal, 50% fat) increases mean systemic exposures of elvitegravir by 87%;1 changes in mean systemic exposures of cobicistat, emtricitabine, and tenofovir alafenamide not clinically important.1

Distribution

Extent

Elvitegravir, cobicistat, tenofovir: Distributed into milk in rats;1 not known whether distributed into human milk.1

Emtricitabine: Distributed into human milk.1

Plasma Protein Binding

Elvitegravir: Approximately 99%.1

Cobicistat: Approximately 98%.1

Emtricitabine: <4%.1

Tenofovir alafenamide: Approximately 80%.1

Elimination

Metabolism

Elvitegravir: Metabolized principally by CYP3A;1 also undergoes glucuronidation via UGT1A1/3.1 Cobicistat, a CYP3A inhibitor, is included in fixed-combination EVG/c/FTC/TAF to inhibit metabolism of and increase plasma concentrations of elvitegravir.1

Cobicistat: Metabolized principally by CYP3A and, to a lesser extent, by CYP2D6.1

Emtricitabine: Converted intracellularly to active 5′-triphosphate metabolite;1 9 not substantially metabolized further.1

Tenofovir alafenamide: Prodrug of tenofovir;1 hydrolyzed intracellularly by cathepsin A to form tenofovir and subsequently metabolized to active metabolite (tenofovir diphosphate).1 9 In vitro, also converted to tenofovir by carboxylesterase 1 in hepatocytes.1 6

Elimination Route

Elvitegravir: 94.8% in feces, 6.7% in urine.1 Unlikely to be removed by hemodialysis or peritoneal dialysis.1

Cobicistat: 86.2% in feces, 8.2% in urine.1 Unlikely to be removed by hemodialysis or peritoneal dialysis.1

Emtricitabine: 70% in urine (glomerular filtration and active tubular secretion), 13.7% in feces.1 Removed by hemodialysis (approximately 30% of a dose over 3 hours);1 not known whether removed by peritoneal dialysis.1

Tenofovir alafenamide: 31.7% in feces, <1% in urine.1 Removed by hemodialysis.1

Half-life

Elvitegravir: 12.9 hours.1

Cobicistat: 3.5 hours.1

Emtricitabine: 10 hours.1

Tenofovir alafenamide: 0.51 hours;1 active metabolite (tenofovir diphosphate) half-life within peripheral blood mononuclear cells is 150–180 hours.1 7

Special Populations

Mild hepatic impairment (Child-Pugh class A): No clinically important effects on pharmacokinetics of tenofovir alafenamide.1

Moderate hepatic impairment (Child-Pugh class B): No clinically important effects on pharmacokinetics of elvitegravir, cobicistat, or tenofovir alafenamide.1 Pharmacokinetics of emtricitabine unlikely to be affected.1

Severe hepatic impairment (Child-Pugh class C): Pharmacokinetics of EVG/c/FTC/TAF not studied.1

Stability

Storage

Oral

Tablets

<30°C.1

Store in original container; keep tightly closed.1

Actions and Spectrum

  • EVG/c/FTC/TAF is a fixed-combination antiretroviral containing elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide.1

  • Elvitegravir (EVG) is an HIV integrase strand transfer inhibitor antiretroviral.1 Inhibits activity of HIV-1 integrase, an enzyme that integrates HIV DNA into the host cell genome.1 Active against HIV-1 and also has some in vitro activity against HIV type 2 (HIV-2);1 inactive against HBV and HCV.1

  • Cobicistat is a mechanism-based CYP3A inhibitor and is included in EVG/c/FTC/TAF as a pharmacokinetic enhancer to decrease elvitegravir metabolism and increase plasma concentrations of the drug (cobicistat-boosted elvitegravir).1 Has no antiretroviral or antiviral activity and is not active against HIV-1, HBV, or HCV.1 Does not antagonize the antiretroviral activity of elvitegravir, emtricitabine, or tenofovir.1

  • Emtricitabine (FTC) is an HIV NRTI.1 218 Inactive until converted intracellularly to an active 5′-triphosphate metabolite.1 26 218 After conversion, active against HIV-1 and also has some in vitro activity against HIV-2.1 218

  • Tenofovir alafenamide (TAF) is a nucleotide reverse transcriptase inhibitor antiretroviral classified as an HIV NRTI.1 Tenofovir alafenamide is a tenofovir prodrug that is inactive until hydrolyzed intracellularly by cathepsin A to form tenofovir and subsequently metabolized by cellular kinases to the active metabolite (tenofovir diphosphate).1 6 7 9 Compared with the tenofovir prodrug tenofovir DF (TDF), tenofovir alafenamide is more stable in blood and plasma and more efficiently converted intracellularly to tenofovir diphosphate, resulting in higher concentrations of active metabolite within HIV target cells and lower circulating concentrations of tenofovir than those reported with tenofovir DF.6 7 9 Active against HIV-1 and also has some in vitro activity against HIV-2;1 221 also active against HBV.221

  • HIV-1 resistant to elvitegravir, emtricitabine, or tenofovir have been produced in vitro and have emerged during EVG/c/FTC/TAF therapy.1 In clinical trials in antiretroviral-naive patients, genotypic resistance to elvitegravir, emtricitabine, and/or tenofovir was identified in HIV-1 isolates from patients who received EVG/c/FTC/TAF and were considered to be virologic treatment failures.1

  • Cross-resistance between elvitegravir and other HIV integrase inhibitors (e.g., dolutegravir, raltegravir) has been reported.1 16 18 22 23 Cross-resistance also occurs among the HIV NRTIs.1

Advice to Patients

  • Critical nature of compliance with HIV therapy and importance of remaining under the care of a clinician.1 Importance of taking as prescribed; do not alter or discontinue antiretroviral regimen without consulting clinician.1

  • Antiretroviral therapy is not a cure for HIV infection;1 opportunistic infections and other complications associated with HIV disease may still occur.1

  • Advise patients that sustained decreases in plasma HIV RNA have been associated with reduced risk of progression to acquired immunodeficiency syndrome (AIDS) and death.1

  • Advise patients that effective antiretroviral regimens can decrease HIV concentrations in blood and genital secretions and strict adherence to such regimens in conjunction with risk-reduction measures may decrease, but cannot absolutely eliminate, the risk of secondary transmission of HIV to others.200 Importance of continuing to practice safer sex (e.g., using latex or polyurethane condoms to minimize sexual contact with body fluids), never sharing personal items that can have blood or body fluids on them (e.g., toothbrushes, razor blades), and never reusing or sharing needles.1 200

  • Importance of reading patient information provided by the manufacturer.1

  • Advise patients that EVG/c/FTC/TAF is a complete regimen for treatment of HIV-1 infection and should not be used in conjunction with other antiretroviral agents.1

  • Importance of taking EVG/c/FTC/TAF with food.1

  • Advise patients that lactic acidosis and severe hepatomegaly with steatosis, including fatalities, have occurred in patients receiving HIV NRTIs, including emtricitabine and/or tenofovir DF, in conjunction with other antiretrovirals.1 Importance of contacting clinician if symptoms suggestive of lactic acidosis or hepatotoxicity (e.g., nausea, vomiting, unusual/unexpected stomach discomfort, weakness) occur.1

  • Inform patients that testing for HBV infection recommended before antiretroviral therapy initiated.1 Also advise patients that severe acute exacerbations of HBV infection have been reported following discontinuance of emtricitabine and/or tenofovir DF in HIV-infected patients coinfected with HBV and may occur with EVG/c/FTC/TAF.1

  • Advise patients that renal impairment, including cases of acute renal failure or Fanconi syndrome, has occurred.1 Importance of not using EVG/c/FTC/TAF concomitantly with or shortly after nephrotoxic agents (e.g., high-dose or multiple NSAIAs).1

  • Advise patients that decreased bone mineral density (BMD) has been reported with EVG/c/FTC/TAF and that assessment of BMD should be considered in those with a history of pathologic bone fracture or other risk factors for osteoporosis or bone loss.1

  • Inform patients that redistribution or accumulation of body fat may occur in patients receiving antiretroviral therapy;1 cause and long-term health effects unknown.1

  • Advise patients that signs and symptoms of inflammation from previous infections may occur soon after initiation of antiretroviral therapy in some individuals with advanced HIV infection (AIDS).1 These symptoms may be due to an improvement in immune response, enabling the body to fight infections that may have been present with no obvious symptoms.1 Importance of immediately informing a healthcare provider if any symptoms of infection occur.1

  • Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs and herbal supplements (e.g., St. John's wort), as well as any concomitant illnesses.1

  • Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.1 Advise HIV-infected women not to breast-feed.1

  • Importance of advising patients of other important precautionary information.1 (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

Elvitegravir, Cobicistat, Emtricitabine, and Tenofovir Alafenamide Fumarate

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Oral

Tablets, film-coated

Elvitegravir 150 mg, Cobicistat 150 mg, Emtricitabine 200 mg, and Tenofovir Alafenamide Fumarate 10 mg (of tenofovir alafenamide)

Genvoya

Gilead

AHFS DI Essentials. © Copyright, 2016, American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland 20814.

Date published: October 22, 2013
Last reviewed: September 29, 2016
Date modified: October 12, 2016

References

1. Gilead Sciences. Genvoya (elvitegravir, cobicistat, emtricitabine, tenofovir alafenamide) tablets prescribing information. Foster City, CA; 2016 Mar.

2. Sax PE, Wohl D, Yin MT et al. Tenofovir alafenamide versus tenofovir disoproxil fumarate, coformulated with elvitegravir, cobicistat, and emtricitabine, for initial treatment of HIV-1 infection: two randomised, double-blind, phase 3, non-inferiority trials. Lancet. 2015; 385:2606-15. [PubMed 25890673]

3. Wohl D, Oka S, Clumeck N et al. Brief Report: A Randomized, Double-Blind Comparison of Tenofovir Alafenamide Versus Tenofovir Disoproxil Fumarate, Each Coformulated With Elvitegravir, Cobicistat, and Emtricitabine for Initial HIV-1 Treatment: Week 96 Results. J Acquir Immune Defic Syndr. 2016; 72:58-64. [PubMed 26829661]

4. Mills A, Arribas JR, Andrade-Villanueva J et al. Switching from tenofovir disoproxil fumarate to tenofovir alafenamide in antiretroviral regimens for virologically suppressed adults with HIV-1 infection: a randomised, active-controlled, multicentre, open-label, phase 3, non-inferiority study. Lancet Infect Dis. 2016; 16:43-52. [PubMed 26538525]

5. Pozniak A, Arribas JR, Gathe J et al. Switching to Tenofovir Alafenamide, Coformulated With Elvitegravir, Cobicistat, and Emtricitabine, in HIV-Infected Patients With Renal Impairment: 48-Week Results From a Single-Arm, Multicenter, Open-Label Phase 3 Study. J Acquir Immune Defic Syndr. 2016; 71:530-7. [PubMed 26627107]

6. Callebaut C, Stepan G, Tian Y et al. In Vitro Virology Profile of Tenofovir Alafenamide, a Novel Oral Prodrug of Tenofovir with Improved Antiviral Activity Compared to That of Tenofovir Disoproxil Fumarate. Antimicrob Agents Chemother. 2015; 59:5909-16. [PubMed 26149992]

7. Ray AS, Fordyce MW, Hitchcock MJ. Tenofovir alafenamide: A novel prodrug of tenofovir for the treatment of Human Immunodeficiency Virus. Antiviral Res. 2016; 125:63-70. [PubMed 26640223]

8. Birkus G, Wang R, Liu X et al. Cathepsin A is the major hydrolase catalyzing the intracellular hydrolysis of the antiretroviral nucleotide phosphonoamidate prodrugs GS-7340 and GS-9131. Antimicrob Agents Chemother. 2007; 51:543-50. [PubMed 17145787]

9. Bonora S, Calcagno A, Trentalange A et al. Elvitegravir, cobicistat, emtricitabine and tenofovir alafenamide for the treatment of HIV in adults. Expert Opin Pharmacother. 2016; 17:409-19. [PubMed 26642079]

14. Mathias AA, German P, Murray BP et al. Pharmacokinetics and pharmacodynamics of GS-9350: a novel pharmacokinetic enhancer without anti-HIV activity. Clin Pharmacol Ther. 2010; 87:322-9. [PubMed 20043009]

15. German P, Liu HC, Szwarcberg J et al. Effect of cobicistat on glomerular filtration rate in subjects with normal and impaired renal function. J Acquir Immune Defic Syndr. 2012; 61:32-40. [PubMed 22732469]

16. Garrido C, Villacian J, Zahonero N et al. Broad phenotypic cross-resistance to elvitegravir in HIV-infected patients failing on raltegravir-containing regimens. Antimicrob Agents Chemother. 2012; 56:2873-8. [PubMed 22450969]

18. Goethals O, Clayton R, Van Ginderen M et al. Resistance mutations in human immunodeficiency virus type 1 integrase selected with elvitegravir confer reduced susceptibility to a wide range of integrase inhibitors. J Virol. 2008; 82:10366-74. [PubMed 18715920]

22. Malet I, Thierry E, Wirden M et al. Combination of two pathways involved in raltegravir resistance confers dolutegravir resistance. J Antimicrob Chemother. 2015; 70:2870-80. [PubMed 26205139]

23. Malet I, Gimferrer Arriaga L, Artese A et al. New raltegravir resistance pathways induce broad cross-resistance to all currently used integrase inhibitors. J Antimicrob Chemother. 2014; 69:2118-22. [PubMed 24710029]

24. US Food and Drug Administration. Center for Drug Evaluation and Research. Application number 203093Orig1s000. Clinical pharmacology and biopharmaceutics review(s). From FDA website.

25. US Food and Drug Administration. Center for Drug Evaluation and Research. Application number 207561Orig1s000. Clinical pharmacology and biopharmaceutics review(s). From FDA website.

26. Akanbi MO, Scarsi KK, Scarci K et al. Combination nucleoside/nucleotide reverse transcriptase inhibitors for treatment of HIV infection. Expert Opin Pharmacother. 2012; 13:65-79. [PubMed 22149368]

177. Merck & Co., Inc. Zepatier (elbasvir and grazoprevir) tablets prescribing information. Whitehouse Station, NJ; 2016 Jan.

200. Panel on Antiretroviral Guidelines for Adults and Adolescents, US Department of Health and Human Services (HHS). Guidelines for the use of antiretroviral agents in HIV-1-infected adults and adolescents (July 14, 2016). Updates may be available at HHS AIDS Information (AIDSinfo) website.

201. Panel on Antiretroviral Therapy and Medical Management of HIV-infected Children, US Department of Health and Human Services (HHS). Guidelines for the use of antiretroviral agents in pediatric HIV infection (March 1, 2016). Updates may be available at HHS AIDS Information (AIDSinfo) website.

202. Panel on Treatment of HIV-Infected Pregnant Women and Prevention of Perinatal Transmission, US Department of Health and Human Services (HHS). Recommendations for use of antiretroviral drugs in pregnant HIV-1-infected women for maternal health and interventions to reduce perinatal HIV transmission in the United States (August 6, 2015). Updates may be available at HHS AIDS Information (AIDSinfo) website.

218. Gilead Sciences. Emtriva (emtricitabine) capsules and oral solution prescribing information. Foster City, CA; 2012 Nov.

221. Gilead Sciences. Viread (tenofovir disoproxil fumarate) tablets and powder for oral use prescribing information. Foster City, CA; 2016 Feb.

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