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Efavirenz

Class: HIV Nonnucleoside Reverse Transcriptase Inhibitors
- Reverse Transcriptase Inhibitors
VA Class: AM800
Chemical Name: (±)-6-Chloro-4-(cyclopropylethynyl)-1,4-dihydro-4-(trifluoromethyl)-2H-3,1-benzoxazin-2-one
Molecular Formula: C14H9ClF3NO2
CAS Number: 154635-17-3
Brands: Sustiva

Efavirenz is also contained as an ingredient in the following combinations:
Efavirenz, Emtricitabine, and Tenofovir Disoproxil Fumarate

Medically reviewed by Drugs.com on May 5, 2021. Written by ASHP.

Warning

    Fixed Combinations
  • If using efavirenz/emtricitabine/tenofovir DF (Atripla), consider that lactic acidosis and severe hepatomegaly with steatosis, including fatalities, have been reported in patients receiving HIV nucleoside reverse transcriptase inhibitors (NRTIs) in conjunction with other antiretrovirals.

  • If using efavirenz/emtricitabine/tenofovir DF (Atripla), consider that severe, acute exacerbations of HBV have been reported following discontinuance of emtricitabine or tenofovir DF in HIV-infected patients coinfected with HBV. The fixed combination is not labeled by FDA for treatment of chronic HBV infection; safety and efficacy not established in HIV-infected patients coinfected with HBV. Monitor hepatic function closely with both clinical and laboratory follow-up for at least several months after the fixed combination is discontinued in coinfected patients. If appropriate, initiation of HBV treatment may be warranted.

Introduction

Antiretroviral; HIV nonnucleoside reverse transcriptase inhibitor (NNRTI).

Uses for Efavirenz

Treatment of HIV Infection

Treatment of HIV-1 infection in adults, adolescents, and pediatric patients ≥3 months of age weighing ≥3.5 kg; usually used in conjunction with 2 NRTIs.

For initial treatment in antiretroviral-naive adults and adolescents, experts state that efavirenz in conjunction with tenofovir alafenamide and emtricitabine or efavirenz in conjunction with tenofovir disoproxil fumarate (tenofovir DF) and emtricitabine (or lamivudine) are alternative NNRTI-based regimens. Efavirenz in conjunction with abacavir and lamivudine (or emtricitabine) is another NNRTI-based regimen option for initial treatment in adults and adolescents when recommended or alternative regimens cannot be used, but use only in those with baseline plasma HIV RNA levels <100,000 copies/mL who are human leukocyte antigen (HLA)-B*5701 negative.

For initial treatment in antiretroviral-naive pediatric patients, experts state that efavirenz and 2 NRTIs is a preferred regimen for initial treatment in children ≥3 to <12 years of age and an alternative regimen for initial treatment in adolescents ≥12 years of age who are not sexually mature. Efavirenz is not recommended for initial treatment in those 3 months to <3 years of age.

Usually avoid efavirenz in pregnant women during first trimester; avoid in women of childbearing age who may become pregnant. (See Fetal/Neonatal Morbidity and Mortality under Cautions.)

Efavirenz/emtricitabine/tenofovir DF fixed combination (Atripla) can be used in adults, adolescents, and children ≥12 years of age weighing ≥40 kg to decrease pill burden and improve adherence; used alone as a complete treatment regimen or used in conjunction with other antiretrovirals.

Postexposure Prophylaxis following Occupational Exposure to HIV (PEP)

Postexposure prophylaxis of HIV infection following occupational exposure (PEP) in health-care personnel and others exposed via percutaneous injury (e.g., needlestick, cut with sharp object) or mucous membrane or nonintact skin (e.g., chapped, abraded, dermatitis) contact with blood, tissue, or other body fluids that might contain HIV.

USPHS recommends 3-drug regimen of raltegravir in conjunction with emtricitabine and tenofovir DF as the preferred regimen for PEP following occupational exposures to HIV. Efavirenz and 2 NRTIs can be considered an alternative regimen, but use for PEP only with expert consultation. Preferred dual NRTI option for PEP regimens is emtricitabine and tenofovir DF (may be given as emtricitabine/tenofovir DF; Truvada); alternative dual NRTIs are tenofovir DF and lamivudine, lamivudine and zidovudine (may be given as lamivudine/zidovudine; Combivir), or zidovudine and emtricitabine.

Management of occupational exposures to HIV is complex and evolving; consult infectious disease specialist, clinician with expertise in administration of antiretroviral agents, and/or National Clinicians’ Postexposure Prophylaxis Hotline (PEPline at 888-448-4911) whenever possible. Do not delay initiation of PEP while waiting for expert consultation.

Postexposure Prophylaxis following Nonoccupational Exposure to HIV (nPEP)

Postexposure prophylaxis of HIV infection following nonoccupational exposure (nPEP) in individuals exposed to blood, genital secretions, or other potentially infectious body fluids that might contain HIV when the exposure represents a substantial risk for HIV transmission. Used in conjunction with other antiretrovirals.

When nPEP indicated in adults and adolescents ≥13 years of age with normal renal function, CDC states preferred regimen is either raltegravir or dolutegravir used in conjunction with emtricitabine and tenofovir DF (given as emtricitabine/tenofovir DF; Truvada); recommended alternative in these patients is ritonavir-boosted darunavir used in conjunction with emtricitabine/tenofovir DF (Truvada).

CDC states efavirenz is an alternative antiretroviral that can be used in nPEP regimens, but use in such regimens only with expert consultation.

Consult infectious disease specialist, clinician with expertise in administration of antiretroviral agents, and/or the National Clinicians’ Postexposure Prophylaxis Hotline (PEPline at 888-448-4911) if nPEP indicated in certain exposed individuals (e.g., pregnant women, children, those with medical conditions such as renal impairment) or if considering a regimen not included in CDC guidelines, source virus is known or likely to be resistant to antiretrovirals, or healthcare provider is inexperienced in prescribing antiretrovirals. Do not delay initiation of nPEP while waiting for expert consultation.

Efavirenz Dosage and Administration

Administration

Oral Administration

Administer efavirenz (Sustiva) or efavirenz/emtricitabine/tenofovir DF (Atripla) orally once daily on an empty stomach, preferably at bedtime.

Administration at bedtime may make adverse CNS effects (dizziness, insomnia, impaired concentration, somnolence, abnormal dreams) more tolerable.

Efavirenz (Sustiva): Use in conjunction with other antiretrovirals.

Efavirenz/emtricitabine/tenofovir DF (Atripla): Use alone as a complete treatment regimen or use in conjunction with other antiretrovirals. Because antiretrovirals in the fixed combination also are available in single-entity or other fixed-combination preparations, take care to ensure that therapy is not duplicated if used in conjunction with other antiretrovirals. (See Use of Fixed Combinations under Cautions.)

Do not use single-entity efavirenz (Sustiva) and efavirenz/emtricitabine/tenofovir DF (Atripla) concomitantly, unless needed for adjustment of efavirenz dosage (e.g., when fixed combination used concomitantly with rifampin).

Capsules (Sustiva)

Swallow capsules whole on an empty stomach.

For adults and pediatric patients ≥3 months of age not able to swallow capsules or tablets, administer capsule contents by mixing with small amount (1–2 teaspoonfuls) of soft food (capsule sprinkle method). Consider mixing with infant formula only if infant cannot consume solid foods. Administer efavirenz mixture within 30 minutes after preparation; do not consume any additional food or infant formula for 2 hours after the mixture.

Mixing capsule contents into food: Add 1–2 teaspoonfuls of age-appropriate soft food (e.g., applesauce, grape jelly, yogurt) to a small container. Hold appropriate number of capsules (see Table 1) horizontally over the small container, twist open, and empty onto the food. Gently mix with a spoon; feed entire mixture to patient. Then, add additional 2 teaspoonfuls of soft food to the small container, stir to disperse remaining efavirenz residue, and feed to patient.

Mixing capsule contents into infant formula: Add 10 mL (2 teaspoonfuls) of reconstituted room temperature infant formula to a 30-mL medicine cup. Hold appropriate number of capsules (see Table 1) horizontally over the medicine cup, twist open, and empty onto the formula. Gently mix with small spoon. Draw up infant formula mixture into 10-mL oral dosing syringe; administer into infant's right or left inner cheek. Then, add additional 2 teaspoonfuls of infant formula to the medicine cup, stir to disperse remaining efavirenz residue, draw up into oral dosing syringe, and administer to infant.

Tablets (Sustiva, Atripla)

Swallow tablets whole on an empty stomach; do not break or crush.

Dosage

Pediatric Patients

Treatment of HIV Infection
Oral

Efavirenz (Sustiva): Dosage in children ≥3 months of age weighing 3.5 to <40 kg is based on weight. (See Table 1.) Adolescents and children weighing ≥40 kg may receive usual adult dosage.

Table 1. Efavirenz (Sustiva) Dosage in Children ≥3 Months of Age Weighing ≥3.5 kg1

Weight in kg

Efavirenz Dosage

Number of Capsules or Tablets

3.5 to <5

100 mg once daily

Two 50-mg capsules

5 to <7.5

150 mg once daily

Three 50-mg capsules

7.5 to <15

200 mg once daily

One 200-mg capsule

15 to <20

250 mg once daily

One 200-mg and one 50-mg capsule

20 to <25

300 mg once daily

One 200-mg and two 50-mg capsules

25 to <32.5

350 mg once daily

One 200-mg and three 50-mg capsules

32.5 to <40

400 mg once daily

Two 200-mg capsules

≥40

600 mg once daily

One 600-mg tablet or three 200-mg capsules

Efavirenz/emtricitabine/tenofovir DF (Atripla) in children ≥12 years of age weighing ≥40 kg: 1 tablet (600 mg of efavirenz, 200 mg of emtricitabine, and 300 mg of tenofovir DF) once daily.

Adults

Treatment of HIV Infection
Oral

Efavirenz (Sustiva): 600 mg once daily.

Efavirenz/emtricitabine/tenofovir DF (Atripla): 1 tablet (efavirenz 600 mg, emtricitabine 200 mg, and tenofovir DF 300 mg) once daily.

Treatment of HIV Infection in Patients Weighing ≥50 kg Receiving Rifampin
Oral

Efavirenz (Sustiva): 800 mg once daily. (See Specific Drugs and Laboratory Tests under Interactions.)

Efavirenz/emtricitabine/tenofovir DF (Atripla): 1 tablet (efavirenz 600 mg, emtricitabine 200 mg, and tenofovir DF 300 mg) once daily and 200 mg of single-entity efavirenz (Sustiva) once daily to provide total efavirenz dosage of 800 mg daily.

Postexposure Prophylaxis of HIV following Occupational Exposure†
Oral

Efavirenz (Sustiva): 600 mg once daily. Use in conjunction with 2 NRTIs (see Postexposure Prophylaxis following Occupational Exposure to HIV under Uses).

Initiate PEP as soon as possible following occupational exposure to HIV (preferably within hours); continue for 4 weeks, if tolerated.

Special Populations

Hepatic Impairment

Treatment of HIV Infection

Efavirenz (Sustiva): Dosage adjustments not needed in patients with mild hepatic impairment; do not use in those with moderate or severe hepatic impairment. (See Hepatic Impairment under Cautions.)

Efavirenz/emtricitabine/tenofovir DF (Atripla): Use usual dosage in patients with mild hepatic impairment; however, caution advised. Do not use in those with moderate or severe hepatic impairment.

Renal Impairment

Treatment of HIV Infection

Efavirenz (Sustiva): Dosage adjustments not needed.

Efavirenz/emtricitabine/tenofovir DF (Atripla): Use usual dosage in patients with Clcr ≥50 mL/minute; do not use in those with Clcr <50 mL/minute.

Geriatric Patients

Select dosage with caution because of age-related decreases in hepatic, renal, and/or cardiac function and concomitant disease and drug therapy.

Cautions for Efavirenz

Contraindications

  • Efavirenz and efavirenz/emtricitabine/tenofovir DF: History of clinically important hypersensitivity reaction (e.g., Stevens-Johnson syndrome, erythema multiforme, toxic skin eruption) to efavirenz or any ingredient in the formulation.

  • Efavirenz/emtricitabine/tenofovir DF: Consider contraindications associated with each drug in the fixed combination.

Warnings/Precautions

Interactions

Efavirenz plasma concentrations may be altered if CYP3A substrates, inhibitors, or inducers used concomitantly. In addition, efavirenz may alter plasma concentrations of drugs metabolized by CYP3A or 2B6. (See Interactions.)

Psychiatric Symptoms

Serious adverse psychiatric symptoms (severe depression, suicidal ideation, nonfatal suicide attempts, aggressive behavior, paranoid reactions) reported rarely in efavirenz clinical studies.

Depression, anxiety, and nervousness also reported in clinical studies. Although causal relationship not established, there have been occasional postmarketing reports of delusions, psychosis-like behavior, catatonia, and death by suicide in patients receiving efavirenz. Aggressive reactions, agitation, emotional lability, mania, neurosis, and paranoia also reported during postmarketing surveillance.

Factors associated with increased occurrence of psychiatric symptoms include history of injection drug use, history of psychiatric disorders, and treatment with antipsychotic drugs at study entry.

If serious psychiatric adverse events occur, evaluate to determine if symptoms are related to efavirenz; if so, determine whether risks of continued efavirenz outweigh benefits.

Nervous System Effects

Dizziness or insomnia reported frequently; abnormal dreams, hallucinations, or impaired concentration also reported. These adverse effects generally begin during first 1–2 days of therapy, improve with continued therapy, and usually resolve after first 2–4 weeks.

Seizures reported, generally in those with a history of seizures. Use with caution in patients with history of seizures. Monitor anticonvulsant plasma concentrations if used in patients receiving anticonvulsants that are metabolized principally by the liver (e.g., phenytoin, phenobarbital). (See Specific Drugs and Laboratory Tests under Interactions.)

Fetal/Neonatal Morbidity and Mortality

May cause fetal harm if administered during first trimester of pregnancy. Teratogenicity demonstrated in animals. Birth defects (including neural tube defects) reported in humans, usually with first-trimester exposure. (See Pregnancy under Cautions.)

Advise women of childbearing potential about the teratogenic potential of efavirenz; perform test to rule out pregnancy before initiating efavirenz or fixed combination containing efavirenz.

Avoid pregnancy during therapy and for 12 weeks after discontinuance of efavirenz or fixed combination containing efavirenz. Women of childbearing potential should use a reliable method of barrier contraception in addition to or instead of a hormonal contraceptive (oral or other hormonal contraceptive). (See Specific Drugs and Laboratory Tests under Interactions.)

Dermatologic and Sensitivity Reactions

Rash (maculopapular skin eruptions) reported frequently. Pruritus; rash associated with blistering, moist desquamation, or ulceration; allergic reaction; photoallergic dermatitis; erythema multiforme; and Stevens-Johnson syndrome also reported.

Median time to rash onset 11 days in adults and 28 days in pediatric patients; median duration 16 days. Mild to moderate rash generally resolves within 1 month with continued efavirenz. May be reinitiated after temporary interruption for rash. Antihistamines and/or corticosteroids may improve tolerability and hasten resolution of rash.

Discontinue in patients with life-threatening cutaneous reactions (e.g., Stevens-Johnson syndrome) and consider alternative therapy.

Discontinue in patients with serious rash (e.g., rash associated with blistering, desquamation, mucosal involvement, or fever).

Hepatotoxicity

Substantial increases in serum AST or ALT concentrations (>5 times ULN) reported in clinical studies in HIV-infected patients coinfected with HBV and/or HCV.

Hepatic failure and hepatitis reported, some with a fulminant course requiring transplantation or resulting in death. Hepatic failure has occurred in some patients with no preexisting hepatic disease or other identifiable risk factors.

Use with caution in patients with hepatic impairment. (See Hepatic Impairment under Cautions.)

Assess serum liver enzyme concentrations prior to and during efavirenz treatment in patients with underlying hepatic disease (including those with HBV and/or HCV infection), patients with markedly increased serum transaminase concentrations, and patients receiving other drugs associated with liver toxicity.

Also consider monitoring serum liver enzymes in patients without preexisting hepatic dysfunction or other risk factors.

In patients with serum hepatic enzyme concentrations >5 times ULN, consider whether benefits of continued efavirenz therapy outweigh risks of hepatotoxicity.

Use of Fixed Combinations

Efavirenz/emtricitabine/tenofovir DF: Consider cautions, precautions, contraindications, and interactions associated with each drug in the fixed combination. Consider cautionary information applicable to specific populations (e.g., pregnant or nursing women, individuals with hepatic or renal impairment, geriatric patients) for each drug.

Do not use efavirenz/emtricitabine/tenofovir DF concomitantly with single-entity efavirenz, unless needed for adjustment of efavirenz dosage (e.g., when fixed combination used concomitantly with rifampin). (See Specific Drugs and Laboratory Tests under Interactions.)

Because the antiretrovirals contained in efavirenz/emtricitabine/tenofovir DF also are available in single-entity or other fixed-combination preparations, take care to ensure that therapy is not duplicated if the fixed combination is used in conjunction with other antiretrovirals.

Do not use efavirenz/emtricitabine/tenofovir DF concomitantly with any preparation containing emtricitabine or tenofovir DF. In addition, do not use concomitantly with any preparation containing lamivudine or with adefovir.

Cardiovascular and Lipid Effects

Prolongation of QT interval corrected for rate (QTc) reported. Consider alternative antiretroviral in patients at increased risk of torsades de pointes and in those receiving a drug known to increase risk of torsades de pointes. (See Interactions.)

Increased serum concentrations of total cholesterol and triglycerides reported. Assess serum cholesterol and triglycerides prior to and periodically during therapy.

Adipogenic Effects

Redistribution or accumulation of body fat, including central obesity, dorsocervical fat enlargement (“buffalo hump”), peripheral wasting, breast enlargement, and general cushingoid appearance, reported in patients receiving antiretroviral therapy.

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

Immune Reconstitution Syndrome

During initial treatment, HIV-infected 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]); this may necessitate further evaluation and treatment.

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

Specific Populations

Pregnancy

Efavirenz may cause fetal harm if administered during first trimester of pregnancy. There are retrospective case reports of neural tube defects in infants born to mothers with first trimester exposure to efavirenz, but prospective pregnancy data not sufficient to adequately assess this risk.

Efavirenz/emtricitabine/tenofovir DF (Atripla): Category D.

Antiretroviral Pregnancy Registry at 800-258-4263 or [Web].

Data from the Antiretroviral Pregnancy Registry show no difference in the risk of overall birth defects for efavirenz compared with background rate for birth defects.

Women of childbearing potential should use effective contraceptive measures during therapy and for 12 weeks after discontinuance of efavirenz or efavirenz/emtricitabine/tenofovir DF. (See Fetal/Neonatal Morbidity and Mortality under Cautions.)

Manufacturer states avoid use during first trimester of pregnancy.

Experts state efavirenz in conjunction with 2 NRTIs is an alternative NNRTI-based regimen for initial treatment in antiretroviral-naive pregnant women, but may be a preferred NNRTI-based regimen for initial treatment when drug interactions with PI-based regimens are a concern or when the convenience of a fixed-combination, single-tablet, once-daily regimen is advantageous. However, these experts state efavirenz should be avoided during first 8 weeks of pregnancy.

Experts also state that antiretroviral regimens that do not include efavirenz should be strongly considered in women who are planning to become pregnant or are sexually active and not using effective contraception, provided such regimens are acceptable to the provider and not expected to compromise the health of the woman.

If a pregnant woman already receiving an efavirenz-containing regimen presents for antenatal care during first trimester, some experts suggest the regimen can be continued if well tolerated and providing adequate virologic suppression. This strategy recognizes that risk of neural tube defects is limited to first 5–6 weeks of pregnancy and pregnancy rarely recognized until after 4–6 weeks and that unnecessary changes in antiretroviral regimens during pregnancy may be associated with loss of virologic control and increased risk of perinatal HIV transmission.

If efavirenz or a fixed combination containing efavirenz is used during first trimester or if pregnancy occurs, apprise patient of potential harm to the fetus.

Lactation

Efavirenz distributed into human milk.

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

Pediatric Use

Efavirenz (Sustiva): Safety and efficacy not evaluated in neonates and infants <3 months of age or who weigh <3.5 kg; not recommended in these pediatric patients. Some experts state efavirenz not recommended for initial treatment in antiretroviral-naive pediatric patients 3 months to <3 years of age.

Efavirenz/emtricitabine/tenofovir DF (Atripla): Safety and efficacy not established in pediatric patients <12 years of age or weighing <40 kg.

Adverse effects reported with efavirenz in pediatric patients 3 months to 21 years of age are similar to those reported in adults with the exception of rash. Rash reported more frequently in children than adults and the incidence of moderate to severe rash has been greater in children than adults.

Not recommended in sexually active adolescent females of childbearing potential who desire to become pregnant or when reliable contraception cannot be ensured. (See Pregnancy under Cautions.)

Geriatric Use

Insufficient experience in those ≥65 years of age to determine whether they respond differently than younger adults.

Select dosage with caution because of age-related decreases in hepatic, renal, and/or cardiac function and concomitant disease and drug therapy.

Hepatic Impairment

Efavirenz (Sustiva): Use with caution in mild hepatic impairment; do not use in moderate or severe hepatic impairment.

Efavirenz/emtricitabine/tenofovir DF (Atripla): Use with caution in mild hepatic impairment; do not use in moderate or severe hepatic impairment.

Monitor hepatic enzyme concentrations in patients with known or suspected HBV or HCV infection, patients with substantially increased transaminase concentrations, and in patients receiving other drugs associated with hepatotoxicity. (See Hepatotoxicity under Cautions.)

Renal Impairment

Efavirenz (Sustiva): Pharmacokinetics not specifically studied; clinically important decreases in clearance not anticipated. (See Renal Impairment under Dosage and Administration.)

Efavirenz/emtricitabine/tenofovir DF (Atripla): Do not use in those with Clcr <50 mL/minute.

Common Adverse Effects

Rash, dizziness, nausea, headache, fatigue, insomnia, vomiting.

Interactions for Efavirenz

Metabolized by CYP3A and CYP2B6.

Inhibits CYP2C9 and CYP2C19 and, to a lesser extent, CYP2D6 and CYP1A2. Does not inhibit CYP2E1.

Induces CYP3A and CYP2B6.

The following drug interactions are based on studies using efavirenz. Drug interaction studies not performed using efavirenz/emtricitabine/tenofovir DF. When fixed combinations are used, consider interactions associated with each drug in the fixed combination.

Drugs Affecting or Metabolized by Hepatic Microsomal Enzymes

Pharmacokinetic interactions likely with drugs that are inhibitors, inducers, or substrates of CYP isoenzymes 3A, 2B6, 2C9, or 2C19 with possible alteration in metabolism of efavirenz and/or other drug.

Specific Drugs and Laboratory Tests

Drug

Interaction

Comments

Abacavir

Clinically important interactions not expected

In vitro evidence of additive antiretroviral effects

Dosage adjustments not needed

Alcohol

Potential for additive CNS effects

Antacids (aluminum hydroxide, magnesium hydroxide, simethicone)

Pharmacokinetic interaction unlikely

Dosage adjustments not needed

Anticoagulants, oral

Warfarin concentrations likely to be affected

Use with caution; closely monitor INR

Anticonvulsants (carbamazepine, phenobarbital, phenytoin)

Carbamazepine: Decreased concentrations and AUCs of efavirenz and carbamazepine

Phenobarbital, phenytoin: Possible decreased concentrations of phenobarbital and phenytoin and/or efavirenz

Carbamazepine: Data insufficient to make dosage recommendations for concomitant use with efavirenz; use with caution and monitor anticonvulsant concentrations; consider alternative anticonvulsant

Phenobarbital, phenytoin: Use caution and monitor anticonvulsant concentrations if used with efavirenz; consider alternative anticonvulsant

Efavirenz/emtricitabine/tenofovir DF: Data insufficient to make dosage recommendations for concomitant use with carbamazepine; use alternative anticonvulsant

Antifungals, azoles (fluconazole, isavuconazonium, itraconazole, ketoconazole, posaconazole, voriconazole)

Fluconazole: No clinically important pharmacokinetic interactions

Isavuconazonium (prodrug of isavuconazole): Possible decreased isavuconazole concentrations

Itraconazole: Decreased concentrations of itraconazole; no change in efavirenz concentrations

Ketoconazole: Possible decreased concentrations of the antifungal

Posaconazole: Decreased posaconazole concentrations and AUC; does not affect efavirenz concentrations

Voriconazole: Decreased voriconazole concentrations; increased efavirenz concentrations

Fluconazole: Dosage adjustments not needed

Isavuconazonium: Consider monitoring isavuconazole concentrations and antifungal efficacy; isavuconazonium dosage adjustments may be needed

Itraconazole: Dosage recommendation for concomitant use not available; consider alternative antifungal; experts state avoid concomitant use; if used concomitantly, closely monitor itraconazole concentrations and adjust antifungal dosage accordingly

Posaconazole: Avoid concomitant use unless potential benefits outweigh risks; if used concomitantly, monitor posaconazole concentrations and adjust antifungal dosage accordingly

Voriconazole: Increase voriconazole maintenance dosage to 400 mg every 12 hours and decrease efavirenz dosage to 300 mg once daily (use efavirenz capsules; do not divide tablet); do not use usual voriconazole dosage with usual efavirenz dosage; concomitant use with efavirenz/emtricitabine/tenofovir DF contraindicated

Antihistamines

Decreased cetirizine concentrations; no change in efavirenz concentrations

When used with cetirizine, dosage adjustments not needed

Antimalarials

Fixed combination of artemether and lumefantrine (artemether/lumefantrine): Decreased concentrations and AUC of artemether and active metabolite of artemether; decreased lumefantrine AUC; may decrease antimalarial effect of artemether/lumefantrine; possible QT interval prolongation

Fixed combination of atovaquone and proguanil (atovaquone/proguanil): Decreased AUC of atovaquone and proguanil;

Artemether/lumefantrine: Consider alternative antimalarial agent; experts state if used concomitantly, monitor for antimalarial efficacy and malaria recurrence

Atovaquone/proguanil: Concomitant use not recommended; experts state consider alternative for malaria prophylaxis, if possible

Antimycobacterials (bedaquiline, rifabutin, rifampin, rifapentine)

Bedaquiline: Possible decreased bedaquiline concentrations

Rifabutin: Decreased rifabutin concentrations; no change in efavirenz AUC

Rifampin: Decreased efavirenz concentrations and AUC

Bedaquiline: Concomitant use not recommended

Rifabutin: Manufacturer of efavirenz states increase daily rifabutin dosage by 50% and consider doubling rifabutin dosage when given 2 or 3 times weekly; experts suggest increase rifabutin dosage to 450–600 mg once daily or 600 mg 3 times weekly, provided regimen does not include a PI

Rifampin: Manufacturer states increase efavirenz dosage to 800 mg once daily in those weighing ≥50 kg; experts recommend efavirenz 600 mg once daily for patients weighing <60 kg and efavirenz 800 mg once daily in those weighing >60 kg and state virologic response should be monitored and therapeutic drug monitoring considered; if using efavirenz/emtricitabine/tenofovir DF, use 1 tablet of fixed combination (see Preparations) and 200 mg of single-entity efavirenz once daily to provide efavirenz dosage of 800 mg daily

Rifapentine: Do not use concomitantly

Antipsychotics (pimozide)

Pimozide: Do not use concomitantly

Atazanavir

Ritonavir-boosted atazanavir: Possible increased atazanavir concentrations and AUC depending on specific regimen

Cobicistat-boosted atazanavir: Decreased atazanavir and cobicistat concentrations; no change in efavirenz concentrations

Unboosted atazanavir: Substantially decreased atazanavir concentrations and AUC; no clinically important change in efavirenz concentrations

No in vitro evidence of antagonistic antiretroviral effects

Ritonavir-boosted atazanavir in treatment-naive adults: Use atazanavir 400 mg and ritonavir 100 mg once daily (with food) and efavirenz 600 mg once daily (without food, preferably at bedtime)

Cobicistat-boosted atazanavir in antiretroviral-naive adults: Use single-entity atazanavir 400 mg and single-entity cobicistat 150 mg once daily (with food) and efavirenz 600 mg once daily (without food, preferably at bedtime)

Ritonavir-boosted or cobicistat-boosted atazanavir in antiretroviral-experienced adults: Concomitant use not recommended

Unboosted atazanavir: Do not use with efavirenz

Efavirenz/emtricitabine/tenofovir DF: Concomitant use with atazanavir (with or without low-dose ritonavir) not recommended

Atovaquone

Decreased atovaquone AUC

Consider alternative treatment for Pneumocystis jirovecii pneumonia (PCP) or toxoplasmosis or consider alternative antiretroviral regimen; if used concomitantly, monitor for atovaquone efficacy

Avanafil

Data not available

Concomitant use not recommended

Benzodiazepines

Midazolam, triazolam: Possible increased midazolam or triazolam concentrations

Lorazepam: Increased lorazepam concentrations, but no effect on lorazepam AUC

Alprazolam: Data not available

Midazolam (oral), triazolam: Do not use concomitantly

Midazolam (parenteral): Experts state a single parenteral midazolam dose can be used with caution in a monitored situation for procedural sedation

Lorazepam: Dosage adjustments not needed

Alprazolam: Monitor for benzodiazepine effectiveness

Buprenorphine

Buprenorphine (sublingual or buccal): Decreased buprenorphine and norbuprenorphine AUCs

Buprenorphine (subdermal implant): Data not available

Buprenorphine (sublingual or buccal): Some experts state dosage adjustments not recommended, but monitor for withdrawal symptoms

Buprenorphine (subdermal implant): If efavirenz initiated after insertion of implant, clinical monitoring recommended

Bupropion

Decreased bupropion concentrations and AUC; increased concentrations of hydroxybupropion (an active metabolite)

Titrate bupropion dosage based on clinical response; do not exceed maximum recommended bupropion dosage

Calcium-channel blocking agents

Diltiazem: Decreased diltiazem concentrations; slightly increased efavirenz concentrations

Other calcium-channel blocking agents that are substrates of CYP 3A4 (e.g., felodipine, nicardipine, nifedipine, verapamil): Possible decreased concentrations of the calcium-channel blocking agent

Diltiazem: Titrate diltiazem dosage based on clinical response; adjustment of efavirenz or efavirenz/emtricitabine/tenofovir DF dosage not needed

Other calcium-channel blocking agents that are substrates of CYP 3A4: Titrate dosage of calcium-channel blocking agent according to clinical response

Cisapride

Do not use concomitantly

Corticosteroids

Dexamethasone: Possible decreased efavirenz concentrations

Dexamethasone: Monitor virologic response; consider alternative corticosteroids for long-term use

Daclatasvir

Decreased daclatasvir trough concentrations

Use daclatasvir dosage of 90 mg once daily

Darunavir

Ritonavir-boosted darunavir: Increased efavirenz AUC; decreased darunavir AUC; clinical importance unknown

Cobicistat-boosted darunavir: Possible decreased darunavir and cobicistat concentrations; possible loss of therapeutic effect and development of resistance to darunavir

No in vitro evidence of antagonistic antiretroviral effects

Ritonavir-boosted darunavir: Usual dosage can be used; some experts recommend close monitoring; consider monitoring plasma concentrations of darunavir and efavirenz

Cobicistat-boosted darunavir: Concomitant use not recommended

Delavirdine

Concomitant use not recommended

Didanosine

In vitro evidence of additive antiretroviral effects

Efavirenz/emtricitabine/tenofovir DF: Use concomitantly with caution and monitor closely for didanosine-associated adverse effects (e.g., pancreatitis, lactic acidosis, neuropathy)

Dolutegravir

Decreased dolutegravir concentrations and AUC; effect on efavirenz pharmacokinetics unlikely

No in vitro evidence of antagonistic antiretroviral effects

Adults: In antiretroviral-naive or antiretroviral-experienced, HIV integrase strand transferase inhibitor-naive (INSTI-naive), use dolutegravir 50 mg twice daily; in INSTI-experienced with documented or suspected INSTI resistance, consider alternative to efavirenz whenever possible

Pediatric patients: In antiretroviral-naive or antiretroviral-experienced, INSTI-naive weighing 30 kg to <40 kg, use dolutegravir 35 mg twice daily; in those weighing ≥40 kg, use dolutegravir 50 mg twice daily; in INSTI-experienced with documented or suspected INSTI resistance, consider alternative to efavirenz whenever possible

Elbasvir and grazoprevir

Fixed combination of elbasvir and grazoprevir (elbasvir/grazoprevir): Substantially decreased elbasvir and grazoprevir concentrations; no clinically important effect on efavirenz concentrations; possible loss of virologic response to elbasvir/grazoprevir

Elbasvir/grazoprevir: Concomitant use contraindicated

Elvitegravir

Cobicistat-boosted elvitegravir: Possible altered concentrations of elvitegravir, cobicistat, and efavirenz

Cobicistat-boosted elvitegravir: Do not use concomitantly

Emtricitabine

Clinically important interactions not expected

In vitro evidence of additive antiretroviral effects

Dosage adjustments not needed

Enfuvirtide

In vitro evidence of additive to synergistic antiretroviral effects

Ergot alkaloids (dihydroergotamine, ergotamine, methylergonovine)

Possible decreased ergot alkaloid concentrations; possible inadequate treatment effect

Do not use concomitantly

If methylergonovine used to treat postpartum hemorrhage in a woman receiving efavirenz, additional uterotonic agents may be needed

Estrogens/Progestins

Oral hormonal contraceptive containing ethinyl estradiol and norgestimate: Substantially decreased concentrations and AUC of norelgestromin and levonorgestrel (metabolites of norgestimate); no effect on peak concentrations or AUC of ethinyl estradiol; no effect on efavirenz concentrations

Etonogestrel (subcutaneous implant): Not studied, but decreased etonogestrel concentrations expected; subcutaneous implant contraceptive failure reported in women receiving efavirenz

Levonorgestrel (subcutaneous implant): Decreased levonorgestrel concentrations; unintended pregnancies reported

Levonorgestrel (oral): Decreased levonorgestrel AUC

Hormonal contraceptives (oral or other hormonal contraceptives): Use a barrier contraceptive as an alternative to or in addition to hormonal contraceptive in women of childbearing potential during and for 12 weeks after efavirenz therapy is discontinued

Levonorgestrel (oral): Efficacy as emergency contraceptive expected to be decreased in women receiving efavirenz

Etravirine

Decreased etravirine concentrations and loss of therapeutic effect

Concomitant use not recommended

Fosamprenavir

Substantially decreased concentrations of amprenavir (active metabolite of fosamprenavir) if used with fosamprenavir (without low-dose ritonavir); additional pharmacokinetic interactions if used with ritonavir-boosted fosamprenavir

In vitro evidence of synergistic antiretroviral effects

Fosamprenavir (without low-dose ritonavir): Appropriate dosages for concomitant use with efavirenz or efavirenz/emtricitabine/tenofovir DF with respect to safety and efficacy not established

Ritonavir-boosted fosamprenavir: Use usual efavirenz dosage with fosamprenavir 1.4 g once daily and ritonavir 300 mg once daily or, alternatively, with fosamprenavir 700 mg twice daily and ritonavir 100 mg twice daily

Efavirenz/emtricitabine/tenofovir DF: If once-daily regimen of ritonavir-boosted fosamprenavir used, increase ritonavir dosage to 300 mg once daily; if a twice-daily regimen of ritonavir-boosted fosamprenavir used, ritonavir dosage adjustment not needed

Histamine H2-receptor antagonists (famotidine)

Pharmacokinetic interaction unlikely with famotidine

When used with famotidine, dosage adjustments not needed

HMG-CoA reductase inhibitors (statins)

Atorvastatin, pravastatin, and simvastatin: Decreased concentrations of the antilipemic agent; no clinically important effect on efavirenz concentrations

Pitavastatin: Decreased AUC and increased concentrations of pitavastatin

Rosuvastatin: Data not available

Atorvastatin: Titrate atorvastatin dosage based on lipid response; do not exceed maximum recommended dosage

Lovastatin: Titrate lovastatin dosage based on lipid response; do not exceed maximum recommended dosage; avoid lovastatin if efavirenz regimen includes a ritonavir-boosted PI

Pitavastatin: Dosage adjustments not necessary

Pravastatin: Titrate pravastatin dosage based on lipid response; do not exceed the maximum recommended dosage

Rosuvastatin: Titrate rosuvastatin dosage based on lipid response; do not exceed maximum recommended dosage

Simvastatin: Titrate simvastatin dosage based on lipid response; do not exceed maximum recommended dosage; avoid simvastatin if efavirenz regimen includes a ritonavir-boosted PI

Immunosuppressive agents (cyclosporine, sirolimus, tacrolimus)

Cyclosporine, sirolimus, tacrolimus: Possible decreased concentrations of the immunosuppressive agents; no effect on efavirenz concentrations

Cyclosporine, sirolimus, tacrolimus: Dosage of immunosuppressive agent may need to be adjusted if used with efavirenz or efavirenz/emtricitabine/tenofovir DF; whenever efavirenz or efavirenz/emtricitabine/tenofovir DF is initiated or discontinued, monitor immunosuppressive agent concentrations for at least 2 weeks until stable

Indinavir

Decreased indinavir AUC; no clinically important effect on efavirenz concentrations or AUC

In vitro evidence of additive antiretroviral effects

Optimum dosage for concomitant use not established; increasing indinavir dosage to 1 g every 8 hours does not compensate for increased indinavir metabolism due to efavirenz

Lamivudine

No effect on lamivudine peak concentrations or AUC

In vitro evidence of additive antiretroviral effects

Dosage adjustments not needed

Ledipasvir and sofosbuvir

Fixed combination of ledipasvir and sofosbuvir (ledipasvir/sofosbuvir): clinically important pharmacokinetic interactions with efavirenz not expected; if used with efavirenz/emtricitabine/tenofovir DF, decreased ledipasvir concentrations but no clinically important effect on sofosbuvir or efavirenz concentrations

Ledipasvir/sofosbuvir: Dosage adjustments not needed if used with efavirenz; if used with efavirenz/emtricitabine/tenofovir DF, monitor for tenofovir-associated adverse effects

Lopinavir/ritonavir

Decreased lopinavir concentrations and AUC

In vitro evidence of additive antiretroviral effects

Once-daily lopinavir/ritonavir regimen not recommended with efavirenz

If efavirenz used with lopinavir in adults, recommended dosage of lopinavir/ritonavir tablets is lopinavir 500 mg/ritonavir 125 mg twice daily; alternatively, recommended dosage of lopinavir/ritonavir oral solution is lopinavir 533 mg/ritonavir 133 mg (6.5 mL) twice daily

Macrolides (azithromycin, clarithromycin, erythromycin)

Risk of QT interval prolongation

Azithromycin: Pharmacokinetic interaction unlikely

Clarithromycin: Decreased clarithromycin concentrations and AUC and increased 14-hydroxyclarithromycin concentrations and AUC

Erythromycin: Not studied

Consider alternative to macrolide antibiotics

Azithromycin: Dosage adjustments not needed

Clarithromycin: Some experts state consider alternative (e.g., azithromycin)

Maraviroc

Decreased maraviroc concentrations and AUC

No in vitro evidence of antagonistic antiretroviral effects

Recommended maraviroc dosage is 600 mg twice daily when used with efavirenz, provided regimen does not include a potent CYP3A inhibitor

Methadone

Decreased methadone concentrations and AUC; opiate withdrawal manifestations required 22% increase in methadone dosage

Inform patients of potential interaction; closely monitor for signs of opiate withdrawal; increased methadone maintenance dosage may be necessary

Nelfinavir

Increased nelfinavir concentrations and AUC; decreased efavirenz concentrations and AUC

In vitro evidence of additive to synergistic antiretroviral effects

Dosage adjustments not needed

Nevirapine

Decreased efavirenz concentrations and AUC; no change in nevirapine concentrations

Increased incidence of adverse effects; no improvement in efficacy

Concomitant use not recommended

Ombitasvir, paritaprevir, and ritonavir

Fixed combination of ombitasvir, paritaprevir, and ritonavir (ombitasvir/paritaprevir/ritonavir) with or without dasabuvir: Concomitant use poorly tolerated; elevated liver enzymes reported

Ombitasvir/paritaprevir/ritonavir with or without dasabuvir: Concomitant use contraindicated

Psychotherapeutic agents

Potential for additive CNS effects

Raltegravir

Decreased raltegravir concentrations and AUC

In vitro evidence of additive to synergistic antiretroviral effects

Dosage adjustments not necessary

Rilpivirine

Decreased rilpivirine concentrations

Concomitant use not recommended

Ritonavir

Increased ritonavir AUC and increased efavirenz AUC

In vitro evidence of additive antiretroviral effects

Monitor hepatic enzymes and monitor patient for adverse effects (e.g., dizziness, nausea, paresthesia) if used with efavirenz or efavirenz/emtricitabine/tenofovir DF

St. John’s wort (Hypericum perforatum)

Decreased efavirenz concentrations; possible loss of virologic response and increased risk of efavirenz resistance

Do not use concomitantly

Saquinavir

Decreased saquinavir concentrations and AUC; decreased efavirenz concentrations and AUC

In vitro evidence of additive antiretroviral effects

Ritonavir-boosted saquinavir: Manufacturer of saquinavir states concomitant use not recommended; appropriate dosages with respect to safety and efficacy not established

Some experts state that usual dosage of ritonavir-boosted saquinavir (saquinavir 1 g twice daily and ritonavir 100 mg twice daily) may be used with efavirenz

Selective serotonin-reuptake inhibitors (SSRIs)

Paroxetine: No clinically important interactions

Sertraline: Decreased sertraline concentrations and AUC

Paroxetine: Dosage adjustments not needed

Sertraline: Adjust sertraline dosage based on clinical response

Simeprevir

Substantially decreased simeprevir concentrations and AUC; may result in loss of simeprevir therapeutic effect

No clinically important effect on efavirenz pharmacokinetics

Concomitant use not recommended

Sofosbuvir

No clinically important effect on sofosbuvir pharmacokinetics

Dosage adjustments not needed for either drug

Sofosbuvir and velpatasvir

Efavirenz/emtricitabine/tenofovir DF): No clinically important effect on pharmacokinetics of sofosbuvir, efavirenz, or emtricitabine; decreased velpatasvir concentrations and AUC and increased tenofovir concentrations and AUC

Concomitant use not recommended

Stavudine

Clinically important interactions not expected

In vitro evidence of additive antiretroviral effects

Dosage adjustments not needed

Tenofovir DF

No effect on concentrations or AUCs of either drug

In vitro evidence of additive to synergistic antiretroviral effects

Dosage adjustments not needed

Tests for cannabinoids

False-positive urine cannabinoid test when screening test used; efavirenz does not bind cannabinoid receptors

Confirm positive cannabinoid screening test with a more specific test

Tipranavir

Ritonavir-boosted tipranavir: Decreased tipranavir concentrations and no change in efavirenz concentrations using tipranavir 500 mg twice daily and ritonavir 100 mg twice daily with efavirenz 600 mg once daily

In vitro evidence of additive antiretroviral effects

Experts state dosage adjustments not necessary

Valproic acid

No evidence of pharmacokinetic interaction

Zidovudine

No effect on zidovudine peak concentrations or AUC

In vitro evidence of additive antiretroviral effects

Dosage adjustments not necessary

Efavirenz Pharmacokinetics

Absorption

Bioavailability

Peak plasma efavirenz concentrations attained within 3–5 hours.

Fixed-combination tablet containing efavirenz 600 mg, emtricitabine 200 mg, and tenofovir DF 300 mg (efavirenz/emtricitabine/tenofovir DF; Atripla) is bioequivalent to a 600-mg efavirenz tablet, 200-mg emtricitabine capsule, and 300-mg tenofovir DF tablet taken simultaneously in fasting state.

Food

Administration with food increases efavirenz bioavailability.

Compared with administration in the fasting state, AUC increased 22 or 17% when a single 600-mg efavirenz dose as capsules was administered with a high-fat, high-calorie meal (894 kcal, 54 g fat, 54% calories from fat) or a reduced-fat normal calorie meal (440 kcal, 2 g fat, 4% calories from fat), respectively.

Compared with administration in the fasting state, AUC increased 28% when a single 600-mg efavirenz dose as tablets was administered with a high-fat, high-calorie meal (1000 kcal, 500–600 kcal from fat).

In healthy adults, 600-mg efavirenz dose administered by opening 200-mg capsules and mixing contents of 3 capsules with 2 teaspoonfuls of soft food (e.g., applesauce, grape jelly, yogurt) or infant formula resulted in efavirenz AUC that met bioequivalency criteria compared with intact capsules administered in fasting state.

Distribution

Extent

Not fully characterized.

Low efavirenz concentrations distributed into CSF.

Animal studies indicate efavirenz crosses placenta in rats, rabbits, and primates. Distributed into human milk.

Plasma Protein Binding

99.5–99.75%.

Elimination

Metabolism

Metabolized by CYP3A and CYP2B6; undergoes subsequent glucuronidation.

Elimination Route

16–61% excreted in feces (principally as unchanged drug) and 14–34% eliminated in urine as unchanged drug (<1%) or metabolites.

Not removed by hemodialysis; probably not removed by peritoneal dialysis.

Half-life

52–76 hours after a single dose and 50–55 hours after multiple doses.

Special Populations

Hepatic impairment: Pharmacokinetics not affected by mild impairment (Child-Pugh class A); data insufficient to determine whether affected by moderate or severe impairment (Child-Pugh class B or C).

Stability

Storage

Oral

Capsules

Efavirenz (Sustiva): 25°C (may be exposed to 15–30°C).

Tablets

Efavirenz (Sustiva): 25°C (may be exposed to 15–30°C).

Efavirenz/emtricitabine/tenofovir DF (Atripla): 25°C (may be exposed to 15–30°C).

Actions and Spectrum

  • Pharmacologically related to other NNRTIs (e.g., delavirdine, etravirine, nevirapine, rilpivirine); differs structurally from these drugs; also differs pharmacologically and structurally from other currently available antiretrovirals.

  • Active against HIV-1; inactive against HIV-2.

  • Inhibits replication of HIV-1 by interfering with viral RNA- and DNA-directed polymerase activities of reverse transcriptase.

  • HIV-1 with reduced susceptibility to efavirenz have been selected in vitro and have emerged during therapy with the drug.

  • Strains of HIV-1 resistant to efavirenz may be cross-resistant to some other NNRTIs (e.g., delavirdine, nevirapine).

  • Cross-resistance between efavirenz and NRTIs unlikely since the drugs bind at difference sites on reverse transcriptase and have difference mechanisms of action. Cross-resistance between efavirenz and PIs unlikely since the drugs have different target enzymes and mechanisms of action.

Advice to Patients

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

  • Importance of using efavirenz in conjunction with other antiretrovirals—not for monotherapy. Efavirenz/emtricitabine/tenofovir DF (Atripla) can be used alone as a complete treatment regimen or can be used in conjunction with other antiretrovirals.

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

  • 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. 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.

  • Importance of reading patient information provided by the manufacturer.

  • Importance of taking efavirenz on an empty stomach, preferably at bedtime.

  • In patients not able to swallow capsules or tablets, importance of patient or caregiver reading and carefully following instructions for mixing and administering capsule contents in small amount of soft food or infant formula.

  • If a dose is missed, patient should take the missed dose as soon as it is remembered, unless it is almost time for next dose. If a dose is missed, do not take a double dose to make up for missed dose.

  • Advise patients that adverse CNS effects (e.g., dizziness, insomnia, impaired concentration, drowsiness, abnormal dreams) are common during first weeks of efavirenz therapy. Taking the drug at bedtime may improve tolerability. Additive effects may occur if used with alcohol or psychoactive drugs. If CNS effects occur, avoid potentially hazardous tasks such as driving or operating machinery.

  • Advise patients that serious psychiatric symptoms (e.g., severe depression, suicide attempts, aggressive behavior, delusions, paranoia, psychosis-like symptoms) have occurred. Importance of informing clinician of any history of mental illness or substance abuse. Importance of seeking immediate medical evaluation if severe psychiatric symptoms occur.

  • Risk of rash. Since rash may be serious, importance of promptly contacting clinician if rash occurs.

  • Redistribution/accumulation of body fat may occur, with as yet unknown long-term health effects.

  • Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs and dietary or herbal products, and any concomitant illnesses.

  • Importance of women using a reliable barrier method of contraception instead of or in addition to a hormonal contraceptive (oral or other hormonal contraceptive) during and for 12 weeks after efavirenz therapy.

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

  • Importance of advising patients of other important precautionary information. (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.

Efavirenz

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Oral

Capsules

50 mg

Sustiva

Bristol-Myers Squibb

200 mg

Sustiva

Bristol-Myers Squibb

Tablets, film-coated

600 mg

Sustiva

Bristol-Myers Squibb

Efavirenz Combinations

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Oral

Tablets, film-coated

600 mg with Emtricitabine 200 mg and Tenofovir Disoproxil Fumarate 300 mg

Atripla

Bristol-Myers Squibb and Gilead

AHFS DI Essentials™. © Copyright 2021, Selected Revisions May 15, 2017. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.

† Use is not currently included in the labeling approved by the US Food and Drug Administration.

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