Does Sustiva (efavirenz) cause side effects?

Sustiva (efavirenz) is a type of reverse transcriptase inhibitor called non-nucleoside reverse transcriptase inhibitor used to treat infections associated with the human immunodeficiency virus (HIV). 

During infection with HIV, the HIV virus multiplies within the body's cells. The newly-formed viruses then are released from the cells and spread throughout the body where they infect other cells. In this manner, the infection continually spreads to new, uninfected cells that the body is continually producing, and HIV infection is perpetuated. 

When producing new viruses, the HIV virus must manufacture new DNA for each virus. Reverse transcriptase is the enzyme that the virus uses to form new DNA. Sustiva directly inhibits the activity of reverse transcriptase and blocks the production of DNA and new viruses. Sustiva does not kill existing HIV virus and it is not a cure for HIV. 

Common side effects of Sustiva include

Serious side effects of Sustiva include

Drug interactions of Sustiva include triazolam, midazolam, bepridil, pimozide, and ergot derivatives should not be combined with Sustiva because Sustiva increases blood levels of these drugs, potentially causing serious adverse effects.

  • St. John's wort should not be combined with Sustiva because it reduces blood levels of Sustiva, leading to possible loss of effectiveness. Sustiva increases the breakdown of saquinavir and indinavir. This leads to lower drug concentrations in the body and reduces the effect of saquinavir and indinavir.
  • Sustiva increases the concentration of ritonavir while ritonavir increases the concentration of Sustiva.
  • Increased drug concentrations may result in more frequent or more serious side effects. 

There are no adequate studies of Sustiva in pregnant women. It is unknown if Sustiva is excreted in breast milk. HIV-infected mothers should not breastfeed because of the risk of transmitting HIV to an infant that is not infected.

What are the important side effects of Sustiva (efavirenz)?

The most common side effects of Efavirenz are:

Other side effects include

  • muscle pain (myalgia),
  • abnormal heartbeats,
  • liver failure,
  • increased cholesterol
  • increased triglyceride levels.
  • drowsiness,
  • abnormal dreams,
  • hallucinations, and
  • difficulty concentrating.

Serious psychiatric adverse effects have been reported in patients taking Efavirenz such as

Immune reconstitution syndrome which is an inflammatory response to infection may occur in patients treated with combination antiretroviral therapy.

Sustiva (efavirenz) side effects list for healthcare professionals

The most significant adverse reactions observed in patients treated with Sustiva are:

  • psychiatric symptoms,
  • nervous system symptoms,
  • rash,
  • hepatotoxicity.

Clinical Trials Experience

Because clinical studies are conducted under widely varying conditions, the adverse reaction rates reported cannot be directly compared to rates in other clinical studies and may not reflect the rates observed in clinical practice.

Adverse Reactions In Adults

The most common (>5% in either Efavirenz treatment group) adverse reactions of at least moderate severity among patients in Study 006 treated with Sustiva in combination with zidovudine/lamivudine or indinavir were rash, dizziness, nausea, headache, fatigue, insomnia, and vomiting.

Selected clinical adverse reactions of moderate or severe intensity observed in ≥2% of Sustivatreated patients in two controlled clinical trials are presented in Table 2.

Table 2: Selected Treatment-Emergenta Adverse Reactions of Moderate or Severe Intensity Reported in ≥2% of Sustiva-Treated Patients in Studies 006 and ACTG 364

Adverse Reactions Study 006 LAM-, NNRTI-, and Protease Inhibitor-Naive Patients Study ACTG 364 NRTI-experienced, NNRTI-, and Protease Inhibitor-Naive Patients
Sustivab + ZDV/LAM
(n=412)
180 weeksc
Sustivab + Indinavir
(n=415)
102 weeksc
Indinavir + ZDV/LAM
(n=401)
76 weeksc
Sustivab + Nelfinavir + NRTIs
(n=64)
71.1 weeksc
Sustivab + NRTIs
(n=65)
70.9 weeksc
Nelfinavir + NRTIs
(n=66)
62.7 weeksc
Body as a Whole
Fatigue 8% 5% 9% 0 2% 3%
Pain 1% 2% 8% 13% 6% 17%
Central and Peripheral Nervous System
Dizziness 9% 9% 2% 2% 6% 6%
Headache 8% 5% 3% 5% 2% 3%
Insomnia 7% 7% 2% 0 0 2%
Concentration impaired 5% 3% <1% 0 0 0
Abnormal dreams 3% 1% 0
Somnolence 2% 2% <1% 0 0 0
Anorexia 1% <1% <1% 0 2% 2%
Gastrointestinal
Nausea 10% 6% 24% 3% 2% 2%
Vomiting 6% 3% 14%
Diarrhea 3% 5% 6% 14% 3% 9%
Dyspepsia 4% 4% 6% 0 0 2%
Abdominal pain 2% 2% 5% 3% 3% 3%
Psychiatric
Anxiety 2% 4% <1%
Depression 5% 4% <1% 3% 0 5%
Nervousness 2% 2% 0 2% 0 2%
Skin & Appendages
Rashd 11% 16% 5% 9% 5% 9%
Pruritus <1% 1% 1% 9% 5% 9%
a Includes adverse events at least possibly related to study drug or of unknown relationship for Study 006. Includes all adverse events regardless of relationship to study drug for Study ACTG 364.
b Sustiva provided as 600 mg once daily.
c Median duration of treatment.
d Includes erythema multiforme, rash, rash erythematous, rash follicular, rash maculopapular, rash petechial, rash pustular, and urticaria for Study 006 and macules, papules, rash, erythema, redness, inflammation, allergic rash, urticaria, welts, hives, itchy, and pruritus for ACTG 364.
— = Not Specified.
ZDV = zidovudine, LAM = lamivudine.

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

Nervous System Symptoms

For 1008 patients treated with regimens containing Sustiva and 635 patients treated with a control regimen in controlled trials, Table 3 lists the frequency of symptoms of different degrees of severity and gives the discontinuation rates for one or more of the following nervous system symptoms:

  • dizziness,
  • insomnia,
  • impaired concentration,
  • somnolence,
  • abnormal dreaming,
  • euphoria,
  • confusion,
  • agitation,
  • amnesia,
  • hallucinations,
  • stupor,
  • abnormal thinking, and
  • depersonalization.

The frequencies of specific central and peripheral nervous system symptoms are provided in Table 2.

Table 3: Percent of Patients with One or More Selected Nervous System Symptomsa,b

Percent of Patients with: Sustiva 600 mg Once Daily
(n=1008) %
Control Groups
(n=635) %
Symptoms of any severity 52.7 24.6
Mild symptomsc 33.3 15.6
Moderate symptomsd 17.4 7.7
Severe symptomse 2.0 1.3
Treatment discontinuation as a result of symptoms 2.1 1.1
a Includes events reported regardless of causality.
b Data from Study 006 and three Phase 2/3 studies.
c“Mild” = Symptoms which do not interfere with patient's daily activities.
d “Moderate” = Symptoms which may interfere with daily activities.
e“Severe” = Events which interrupt patient's usual daily activities.

Psychiatric Symptoms

Serious psychiatric adverse experiences have been reported in patients treated with Sustiva. In controlled trials, psychiatric symptoms observed at a frequency greater than 2% among patients treated with Sustiva or control regimens, respectively, were

Rash

In controlled clinical trials, the frequency of rash (all grades, regardless of causality) was 26% for 1008 adults treated with regimens containing Sustiva and 17% for 635 adults treated with a control regimen. Most reports of rash were mild or moderate in severity.

The frequency of Grade 3 rash was 0.8% for Sustiva-treated patients and 0.3% for control groups, and the frequency of  Grade 4 rash was 0.1% for Sustiva and 0 for control groups. The discontinuation rates as a result of rash were 1.7% for Sustiva-treated patients and 0.3% for control groups.

Experience with Sustiva in patients who discontinued other antiretroviral agents of the NNRTI class is limited. Nineteen patients who discontinued nevirapine because of rash have been treated with Sustiva. Nine of these patients developed mild-to-moderate rash while receiving therapy with Sustiva, and two of these patients discontinued because of rash.

Laboratory Abnormalities

Selected Grade 3-4 laboratory abnormalities reported in ≥2% of Sustiva-treated patients in two clinical trials are presented in Table 4.

Table 4: Selected Grade 3-4 Laboratory Abnormalities Reported in ≥2% of Sustiva-Treated Patients in Studies 006 and ACTG 364

Variable Limit Study 006 LAM-, NNRTI-, and Protease Inhibitor-Naive Patients Study ACTG 364 NRTI-experienced, NNRTI-, and Protease Inhibitor-Naive Patients
Sustivaa + ZDV/LAM
(n=412) 180 weeksb
Sustivaa + Indinavir
(n=415) 102 weeksb
Indinavir + ZDV/LAM
(n=401) 76 weeksb
Sustivaa + Nelfinavir + NRTIs
(n=64) 71.1 weeksb
Sustivaa + NRTIs
(n=65) 70.9 weeksb
Nelfinavir + NRTIs
(n=66) 62.7 weeksb
Chemistry
ALT >5 x ULN 5% 8% 5% 2% 6% 3%
AST >5 x ULN 5% 6% 5% 6% 8% 8%
GGTc >5 x ULN 8% 7% 3% 5% 0 5%
Amylase >2 x ULN 4% 4% 1% 0 6% 2%
Glucose >250 mg/dL 3% 3% 3% 5% 2% 3%
Triglyceridesd ≥751 mg/dL 9% 6% 6% 11% 8% 17%
Hematology
Neutrophils <750/mm³ 10% 3% 5% 2% 3% 2%
a Sustiva provided as 600 mg once daily.
bMedian duration of treatment.
cIsolated elevations of GGT in patients receiving Sustiva may reflect enzyme induction not associated with liver toxicity.
d Nonfasting.
ZDV = zidovudine, LAM = lamivudine, ULN = upper limit of normal, ALT = alanine aminotransferase, AST = aspartate aminotransferase, GGT = gamma-glutamyltransferase.

Patients Coinfected With Hepatitis B Or C
  • Liver function tests should be monitored in patients with a history of hepatitis B and/or C.
  • In the long-term data set from Study 006, 137 patients treated with Sustiva-containing regimens  (median duration of therapy, 68 weeks) and 84 treated with a control regimen (median duration, 56 weeks) were seropositive at screening for hepatitis B (surface antigen positive) and/or C (hepatitis C antibody positive).
  • Among these coinfected patients, elevations in AST to greater than five times ULN developed in 13% of patients in the Sustiva arms and 7% of those in the control arm, and elevations in ALT to greater than five times ULN developed in 20% of patients in the Sustiva arms and 7% of patients in the control arm.
  • Among coinfected patients, 3% of those treated with Sustiva-containing regimens and 2% in the control arm discontinued from the study because of liver or biliary system disorders.
Lipids
  • Increases from baseline in total cholesterol of 10-20% have been observed in some uninfected volunteers receiving Sustiva.
  • In patients treated with Sustiva + zidovudine + lamivudine, increases from baseline in nonfasting total cholesterol and HDL of approximately 20% and 25%, respectively, were observed.
  • In patients treated with Sustiva + indinavir, increases from baseline in nonfasting cholesterol and HDL of approximately 40% and 35%, respectively, were observed. Nonfasting total cholesterol levels =240 mg/dL and =300 mg/dL were reported in 34% and 9%, respectively, of patients treated with Sustiva + zidovudine + lamivudine; 54% and 20%, respectively, of patients treated with Sustiva + indinavir; and 28% and 4%, respectively, of patients treated with indinavir + zidovudine + lamivudine.
  • The effects of Sustiva on triglycerides and LDL in this study were not well characterized since samples were taken from nonfasting patients. The clinical significance of these findings is unknown.

Adverse Reactions In Pediatric Patients

  • Because clinical studies are conducted under widely varying conditions, the adverse reaction rates reported cannot be directly compared to rates in other clinical studies and may not reflect the rates observed in clinical practice.
  • Assessment of adverse reactions is based on three clinical trials in 182 HIV-1 infected pediatric patients (3 months to 21 years of age) who received Sustiva in combination with other antiretroviral agents for a median of 123 weeks.
  • The adverse reactions observed in the three trials were similar to those observed in clinical trials in adults except that rash was more common in pediatric patients (32% for all grades regardless of causality) and more often of higher grade (ie, more severe).
  • Two (1.1%) pediatric patients experienced Grade 3 rash (confluent rash with fever, generalized rash), and four (2.2%) pediatric patients had Grade 4 rash (all erythema multiforme).
  • Five pediatric patients (2.7%) discontinued from the study because of rash.

Postmarketing Experience

The following adverse reactions have been identified during postapproval use of Sustiva. Because these reactions are reported voluntarily from a population of unknown size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

  • Body as a Whole: allergic reactions, asthenia, redistribution/accumulation of body fat
  • Central and Peripheral Nervous System: abnormal coordination, ataxia, encephalopathy, cerebellar coordination and balance disturbances, convulsions, hypoesthesia, paresthesia, neuropathy, tremor, vertigo
  • Endocrine: gynecomastia
  • Gastrointestinal: constipation, malabsorption
  • Cardiovascular: flushing, palpitations
  • Liver and Biliary System: hepatic enzyme increase, hepatic failure, hepatitis.
  • Metabolic and Nutritional: hypercholesterolemia, hypertriglyceridemia
  • Musculoskeletal: arthralgia, myalgia, myopathy
  • Psychiatric: aggressive reactions, agitation, delusions, emotional lability, mania, neurosis, paranoia, psychosis, suicide, catatonia
  • Respiratory: dyspnea
  • Skin and Appendages: erythema multiforme, photoallergic dermatitis, Stevens-Johnson syndrome
  • Special Senses: abnormal vision, tinnitus

What drugs interact with Sustiva (efavirenz)?

Potential For Sustiva To Affect Other Drugs

  • Efavirenz has been shown in vivo to induce CYP3A and CYP2B6. Other compounds that are substrates of CYP3A or CYP2B6 may have decreased plasma concentrations when coadministered with Sustiva.

Potential For Other Drugs To Affect Sustiva

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

QT Prolonging Drugs

  • There is limited information available on the potential for a pharmacodynamic interaction between Sustiva and drugs that prolong the QTc interval. QTc prolongation has been observed with the use of Efavirenz. Consider alternatives to Sustiva when coadministered with a drug with a known risk of Torsade de Pointes.

Established And Other Potentially Significant Drug Interactions

Drug interactions with Sustiva are summarized in Table 5. For pharmacokinetics data, Tables 7 and 8. This table includes potentially significant interactions, but is not all inclusive.

Table 5: Established and Other Potentially Significant Drug Interactions: Alteration in Dose or Regimen May Be Recommended Based on Drug Interaction Studies or Predicted Interaction

Concomitant Drug Class: Drug NameEffectClinical Comment
HIV antiviral agents
Protease inhibitor: Fosamprenavir Calcium↓amprenavirFosamprenavir (unboosted): Appropriate doses of the combinations with respect to safety and efficacy have not been established.
Fosamprenavir/ritonavir: An additional 100 mg/day (300 mg total) of ritonavir is recommended when Sustiva is administered with fosamprenavir/ritonavir once daily. No change in the ritonavir dose is required when Sustiva is administered with fosamprenavir plus ritonavir twice daily.
Protease inhibitor: Atazanavir↓atazanavir*Treatment-naive patients: When coadministered with Sustiva, the recommended dose of atazanavir is 400 mg with ritonavir 100 mg (together once daily with food) and Sustiva 600 mg (once daily on an empty stomach, preferably at bedtime).
Treatment-experienced patients: Coadministration of Sustiva and atazanavir is not recommended.
Protease inhibitor: Indinavir↓ indinavir*The optimal dose of indinavir, when given in combination with Sustiva, is not known. Increasing the indinavir dose to 1000 mg every 8 hours does not compensate for the increased indinavir metabolism due to Sustiva.
Protease inhibitor: Lopinavir/ritonavir↓ lopinavir*Lopinavir/ritonavir once daily dosing is not recommended when coadministered with Sustiva. The dose of lopinavir/ritonavir must be increased when coadministered with Sustiva. See the lopinavir/ritonavir prescribing information for dose adjustments of lopinavir/ritonavir when coadministered with Efavirenz in adult and pediatric patients.
Protease inhibitor: Ritonavir↑ ritonavir*
↑ Efavirenz*
Monitor for elevation of liver enzymes and for adverse clinical experiences (e.g., dizziness, nausea, paresthesia) when Sustiva is coadministered with ritonavir.
Protease inhibitor: Saquinavir↓ saquinavir*Appropriate doses of the combination of Sustiva and saquinavir/ritonavir with respect to safety and efficacy have not been established.
NNRTI: Other NNRTIs↑ or ↓ Efavirenz and/or NNRTICombining two NNRTIs has not been shown to be beneficial. Sustiva should not be coadministered with other NNRTIs.
CCR5 co-receptor antagonist: Maraviroc↓maraviroc*Refer to the full prescribing information for maraviroc for guidance on coadministration with Efavirenz.
Hepatitis C antiviral agents
Boceprevir↓ boceprevir*Concomitant administration of boceprevir with Sustiva is not recommended because it may result in loss of therapeutic effect of boceprevir.
Elbasvir/Grazoprevir↓ elbasvir
↓grazoprevir
Coadministration of Sustiva with elbasvir/grazoprevir is contraindicated because it may lead to loss of virologic response to elbasvir/grazoprevir.
Pibrentasvir/Glecaprevir↓ pibrentasvir
↓ glecaprevir
Coadministration of Sustiva is not recommended because it may lead to reduced therapeutic effect of pibrentasvir/glecaprevir.
Simeprevir↓ simeprevir*
↔ Efavirenz*
Concomitant administration of simeprevir with Sustiva is not recommended because it may result in loss of therapeutic effect of simeprevir.
Velpatasvir/ Sofosbuvir↓ velpatasvirCoadministration of Sustiva and sofosbuvir/velpatasvir is not recommended because it may result in loss of therapeutic effect of sofosbuvir/velpatasvir.
Velpatasvir /Sofosbuvir/ /Voxilaprevir↓velpatasvir
↓voxilaprevir
Coadministration of Sustiva and sofosbuvir/velpatasvir/voxilaprevir is not recommended because it may result in loss of therapeutic effect of sofosbuvir/velpatasvir/voxilaprevir.
Other agents
Anticoagulant: Warfarin↑ or ↓warfarinMonitor INR and adjust warfarin dosage if necessary.
Anticonvulsants: Carbamazepine↓ carbamazepine*
↓ Efavirenz*
There are insufficient data to make a dose recommendation for Efavirenz. Alternative anticonvulsant treatment should be used.
Phenytoin Phenobarbital↓ anticonvulsant
?Efavirenz
Potential for reduction in anticonvulsant and/or Efavirenz plasma levels; periodic monitoring of anticonvulsant plasma levels should be conducted.
Antidepressants: Bupropion Sertraline↓ bupropion*
↓ sertraline*
Increases in bupropion dosage should be guided by clinical response. Bupropion dose should not exceed the maximum recommended dose. Increases in sertraline dosage should be guided by clinical response.
Antifungals: Voriconazole↓ voriconazole*
↑ Efavirenz*
Sustiva and voriconazole should not be coadministered at standard doses. When voriconazole is coadministered with Sustiva, voriconazole maintenance dose should be increased to 400 mg every 12 hours and Sustiva dose should be decreased to 300 mg once daily using the capsule formulation. Sustiva tablets must not be broken.
Itraconazole↓itraconazole* ↓ hydroxyitraconazole *Consider alternative antifungal treatment because no dose recommendation for itraconazole can be made.
Ketoconazole↓ ketoconazoleConsider alternative antifungal treatment because no dose recommendation for ketoconazole can be made.
Posaconazole↓posaconazole*Avoid concomitant use unless the benefit outweighs the risks.
Anti-infective: Clarithromycin↓ clarithromycin*
↑ 14-OH metabolite*
Consider alternatives to macrolide antibiotics because of the risk of QT interval prolongation.
Antimycobacterials: Rifabutin Rifampin↓rifabutin*
↓ Efavirenz*
Increase daily dose of rifabutin by 50%. Consider doubling the rifabutin dose in regimens where rifabutin is given 2 or 3 times a week. Increase Sustiva to 800 mg once daily when coadministered with rifampin to patients weighing 50 kg or more.
Antimalarials: Artemether/ lumefantrine
Atovaquone/ proguanil
↓ artemether*
↓dihydroartemisinin*
↓ lumefantrine*
↓atovaquone
↓proguanil
Consider alternatives to artemether/lumefantrine because of the risk of QT interval prolongation. Concomitant administration is not recommended.
Calcium channel blockers: Diltiazem
Others (eg, felodipine, nicardipine, nifedipine, verapamil)
↓ diltiazem*
↓ desacetyl diltiazem*
↓ N-monodesmethyl diltiazem*
↓ calcium channel blocker
Diltiazem dose adjustments should be guided by clinical response (refer to the full prescribing information for diltiazem). No dose adjustment of Efavirenz is necessary when administered with diltiazem.
When coadministered with Sustiva, dosage adjustment of calcium channels blocker may be needed and should be guided by clinical response (refer to the full prescribing information for the calcium channel blocker).
HMG-CoA reductase inhibitors: Atorvastatin
Pravastatin
Simvastatin
↓ atorvastatin*
↓ pravastatin*
↓simvastatin*
Plasma concentrations of atorvastatin, pravastatin, and simvastatin decreased. Consult the full prescribing information for the HMG-CoA reductase inhibitor for guidance on individualizing the dose.
Hormonal contraceptives: Oral Ethinyl estradiol/ Norgestimate Implant Etonogestrel↓active metabolites of norgestimate*
↓ etonogestrel
A reliable method of barrier contraception should be used in addition to hormonal contraceptives.
A reliable method of barrier contraception should be used in addition to hormonal contraceptives. Decreased exposure of etonogestrel may be expected. There have been postmarketing reports of contraceptive failure with etonogestrel in Efavirenz-exposed patients.
Immunosuppressants: Cyclosporine, tacrolimus, sirolimus, and others metabolized by CYP3A↓ immunosuppressantDose adjustments of the immunosuppressant may be required. Close monitoring of immunosuppressant concentrations for at least 2 weeks (until stable concentrations are reached) is recommended when starting or stopping treatment with Efavirenz.
Narcotic analgesic: Methadone↓ methadone*Monitor for signs of methadone withdrawal and increase methadone dose if required to alleviate withdrawal symptoms.
* The interaction between Sustiva and the drug was evaluated in a clinical study. All other drug interactions shown are predicted.

This table is not all-inclusive.

Drugs Without Clinically Significant Interactions With Sustiva

No dosage adjustment is recommended when Sustiva is given with the following:

Cannabinoid Test Interaction

  • Efavirenz does not bind to cannabinoid receptors.
  • False-positive urine cannabinoid test results have been reported with some screening assays in uninfected and HIV-infected subjects receiving Efavirenz.
  • Confirmation of positive screening tests for cannabinoids by a more specific method is recommended.

Treatment & Diagnosis

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Medically Reviewed on 12/2/2020
References
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Professional side effects and drug interactions sections courtesy of the U.S. Food and Drug Administration.