Drug Interactions
Efavirenz plasma concentrations may be altered by substrates, inhibitors, or
inducers of CYP3A. Likewise, efavirenz may alter plasma concentrations of drugs
metabolized by CYP3A [see CONTRAINDICATIONS and DRUG INTERACTIONS].
Resistance
SUSTIVA must not be used as a single agent to treat HIV-1 infection or added on as a sole agent to a failing regimen. Resistant virus emerges rapidly when efavirenz is administered as monotherapy. The choice of new antiretroviral agents to be used in combination with efavirenz should take into consideration the potential for viral cross-resistance.
Coadministration with Related Products
Coadministration of SUSTIVA with ATRIPLA (efavirenz 600 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) is not recommended, since efavirenz is one of its active ingredients.
Psychiatric Symptoms
Serious psychiatric adverse experiences have been reported in patients treated
with SUSTIVA. In controlled trials of 1008 patients treated with regimens containing
SUSTIVA for a mean of 2.1 years and 635 patients treated with control regimens
for a mean of 1.5 years, the frequency (regardless of causality) of specific
serious psychiatric events among patients who received SUSTIVA or control regimens,
respectively, were severe depression (2.4%, 0.9%), suicidal ideation (0.7%,
0.3%), nonfatal suicide attempts (0.5%, 0), aggressive behavior (0.4%, 0.5%),
paranoid reactions (0.4%, 0.3%), and manic reactions (0.2%, 0.3%). When psychiatric
symptoms similar to those noted above were combined and evaluated as a group
in a multifactorial analysis of data from Study 006, treatment with efavirenz
was associated with an increase in the occurrence of these selected psychiatric
symptoms. Other factors associated with an increase in the occurrence of these
psychiatric symptoms were history of injection drug use, psychiatric history,
and receipt of psychiatric medication at study entry; similar associations were
observed in both the SUSTIVA and control treatment groups. In Study 006, onset
of new serious psychiatric symptoms occurred throughout the study for both SUSTIVA-treated
and control-treated patients. One percent of SUSTIVA-treated patients discontinued
or interrupted treatment because of one or more of these selected psychiatric
symptoms. There have also been occasional postmarketing reports of death by
suicide, delusions, and psychosis-like behavior, although a causal relationship
to the use of SUSTIVA cannot be determined from these reports. Patients with
serious psychiatric adverse experiences should seek immediate medical evaluation
to assess the possibility that the symptoms may be related to the use of SUSTIVA,
and if so, to determine whether the risks of continued therapy outweigh the
benefits. See ADVERSE REACTIONS.
Nervous System Symptoms
Fifty-three percent (531/1008) of patients receiving SUSTIVA in controlled
trials reported central nervous system symptoms (any grade, regardless of causality)
compared to 25% (156/635) of patients receiving control regimens [see ADVERSE
REACTIONS, Table 4]. These symptoms included, but were not limited to,
dizziness (28.1% of the 1008 patients), insomnia (16.3%), impaired concentration
(8.3%), somnolence (7.0%), abnormal dreams (6.2%), and hallucinations (1.2%).
These symptoms were severe in 2.0% of patients, and 2.1% of patients discontinued
therapy as a result. These symptoms usually begin during the first or second
day of therapy and generally resolve after the first 2-4 weeks of therapy. After
4 weeks of therapy, the prevalence of nervous system symptoms of at least moderate
severity ranged from 5% to 9% in patients treated with regimens containing SUSTIVA
and from 3% to 5% in patients treated with a control regimen. Patients should
be informed that these common symptoms were likely to improve with continued
therapy and were not predictive of subsequent onset of the less frequent psychiatric
symptoms [see WARNINGS AND PRECAUTIONS]. Dosing at bedtime may improve
the tolerability of these nervous system symptoms [see DOSAGE
AND ADMINISTRATION].
Analysis of long-term data from Study 006 (median follow-up 180 weeks, 102 weeks, and 76 weeks for patients treated with SUSTIVA + zidovudine + lamivudine, SUSTIVA + indinavir, and indinavir + zidovudine + lamivudine, respectively) showed that, beyond 24 weeks of therapy, the incidences of new-onset nervous system symptoms among SUSTIVA-treated patients were generally similar to those in the indinavir-containing control arm.
Patients receiving SUSTIVA should be alerted to the potential for additive central nervous system effects when SUSTIVA is used concomitantly with alcohol or psychoactive drugs.
Patients who experience central nervous system symptoms such as dizziness, impaired concentration, and/or drowsiness should avoid potentially hazardous tasks such as driving or operating machinery.
Reproductive Risk Potential
Pregnancy Category D. Efavirenz may cause fetal harm when administered
during the first trimester to a pregnant woman. Pregnancy should be avoided
in women receiving SUSTIVA. Barrier contraception must always be used in combination
with other methods of contraception (eg., oral or other hormonal contraceptives).
Because of the long half-life of efavirenz, use of adequate contraceptive measures
for 12 weeks after discontinuation of SUSTIVA is recommended. Women of childbearing
potential should undergo pregnancy testing before initiation of SUSTIVA. If
this drug is used during the first trimester of pregnancy, or if the patient
becomes pregnant while taking this drug, the patient should be apprised of the
potential harm to the fetus.
There are no adequate and well-controlled studies in pregnant women. SUSTIVA should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus, such as in pregnant women without other therapeutic options.
Antiretroviral Pregnancy Registry: To monitor fetal outcomes of pregnant
women exposed to SUSTIVA, an Antiretroviral Pregnancy Registry has been established.
Physicians are encouraged to register patients by calling 1-800-258-4263.
As of July 2008, the Antiretroviral Pregnancy Registry has received prospective reports of 526 pregnancies exposed to efavirenz-containing regimens, nearly all of which were first-trimester exposures (507 pregnancies). Birth defects occurred in 13 of 407 live births (first trimester exposure) and 2 of 37 live births (second/third-trimester exposure). One of these prospectively reported defects with first-trimester exposure was a neural tube defect. A single case of anophthalmia with first-trimester exposure to efavirenz has also been prospectively reported; however, this case included severe oblique facial clefts and amniotic banding, a known association with anophthalmia. There have been five retrospective reports of findings consistent with neural tube defects, including meningomyelocele. All mothers were exposed to efavirenz containing regimens in the first trimester. Although a causal relationship of these events to the use of SUSTIVA has not been established, similar defects have been observed in preclinical studies of efavirenz.
Malformations have been observed in 3 of 20 fetuses/infants from efavirenz-treated cynomolgus monkeys (versus 0 of 20 concomitant controls) in a developmental toxicity study. The pregnant monkeys were dosed throughout pregnancy (postcoital days 20-150) with efavirenz 60 mg/kg daily, a dose which resulted in plasma drug concentrations similar to those in humans given 600 mg/day of SUSTIVA. Anencephaly and unilateral anophthalmia were observed in one fetus, microophthalmia was observed in another fetus, and cleft palate was observed in a third fetus. Efavirenz crosses the placenta in cynomolgus monkeys and produces fetal blood concentrations similar to maternal blood concentrations. Efavirenz has been shown to cross the placenta in rats and rabbits and produces fetal blood concentrations of efavirenz similar to maternal concentrations. An increase in fetal resorptions was observed in rats at efavirenz doses that produced peak plasma concentrations and AUC values in female rats equivalent to or lower than those achieved in humans given 600 mg once daily of SUSTIVA. Efavirenz produced no reproductive toxicities when given to pregnant rabbits at doses that produced peak plasma concentrations similar to and AUC values approximately half of those achieved in humans given 600 mg once daily of SUSTIVA.
Rash
In controlled clinical trials, 26% (266/1008) of patients treated with 600
mg SUSTIVA experienced new-onset skin rash compared with 17% (111/635) of patients
treated in control groups [see ADVERSE REACTIONS,
Table 5]. Rash associated with blistering, moist desquamation, or ulceration
occurred in 0.9% (9/1008) of patients treated with SUSTIVA. The incidence of
Grade 4 rash (eg, erythema multiforme, Stevens-Johnson syndrome) in patients
treated with SUSTIVA in all studies and expanded access was 0.1%. Rashes are
usually mild-to-moderate maculopapular skin eruptions that occur within the
first 2 weeks of initiating therapy with efavirenz (median time to onset of
rash in adults was 11 days) and, in most patients continuing therapy with efavirenz,
rash resolves within 1 month (median duration, 16 days). The discontinuation
rate for rash in clinical trials was 1.7% (17/1008). SUSTIVA can be reinitiated
in patients interrupting therapy because of rash. SUSTIVA should be discontinued
in patients developing severe rash associated with blistering, desquamation,
mucosal involvement, or fever. Appropriate antihistamines and/or corticosteroids
may improve the tolerability and hasten the resolution of rash.
Rash was reported in 26 of 57 pediatric patients (46%) treated with SUSTIVA
capsules [see ADVERSE REACTIONS]. One pediatric patient experienced Grade
3 rash (confluent rash with fever), and two patients had Grade 4 rash (erythema
multiforme). The median time to onset of rash in pediatric patients was 8 days.
Prophylaxis with appropriate antihistamines before initiating therapy with SUSTIVA
in pediatric patients should be considered.
Liver Enzymes
In patients with known or suspected history of hepatitis B or C infection and
in patients treated with other medications associated with liver toxicity, monitoring
of liver enzymes is recommended. In patients with persistent elevations of serum
transaminases to greater than five times the upper limit of the normal range,
the benefit of continued therapy with SUSTIVA needs to be weighed against the
unknown risks of significant liver toxicity [see ADVERSE REACTIONS and
Use in Specific Populations].
Convulsions
Convulsions have been observed in patients receiving efavirenz, generally in
the presence of known medical history of seizures [see Nonclinical Toxicology].
Caution must be taken in any patient with a history of seizures. Patients who
are receiving concomitant anticonvulsant medications primarily metabolized by
the liver, such as phenytoin and phenobarbital, may require periodic monitoring
of plasma levels [see DRUG INTERACTIONS].
Lipid Elevations
Treatment with SUSTIVA has resulted in increases in the concentration of total
cholesterol and triglycerides [see ADVERSE REACTIONS]. Cholesterol and
triglyceride testing should be performed before initiating SUSTIVA therapy and
at periodic intervals during therapy.
Immune Reconstitution Syndrome
Immune reconstitution syndrome has been reported in patients treated with combination
antiretroviral therapy, including SUSTIVA. During the initial phase of combination
antiretroviral treatment, patients whose immune system responds may develop
an inflammatory response to indolent or residual opportunistic infections [such
as Mycobacterium avium infection, cytomegalovirus, Pneumocystis jiroveci
pneumonia (PCP), or tuberculosis], which may necessitate further evaluation
and treatment.
Fat Redistribution
Redistribution/accumulation of body fat including central obesity, dorsocervical fat enlargement (buffalo hump), peripheral wasting, facial wasting, breast enlargement, and "cushingoid appearance" have been observed in patients receiving antiretroviral therapy. The mechanism and long-term consequences of these events are currently unknown. A causal relationship has not been established.
Patient Counseling Information
See FDA-Approved Patient Labeling.
Drug Interactions
A statement to patients and healthcare providers is included on the product's
bottle labels: ALERT: Find out about medicines that should NOT be taken with
SUSTIVA.
SUSTIVA may interact with some drugs; therefore, patients should be advised to report to their doctor the use of any other prescription, nonprescription medication, or herbal products, particularly St. John's
Wort.
General Information for Patients
Patients should be informed that SUSTIVA is not a cure for HIV-1 infection and that they may continue to experience illnesses associated with HIV-1 infection, including opportunistic infections. Patients should remain under the care of a physician while taking SUSTIVA. Patients should be told that the use of SUSTIVA has not been shown to reduce the risk of transmitting HIV-1 to others through sexual contact or blood contamination.
Dosing Instructions
Patients should be advised to take SUSTIVA every day as prescribed. SUSTIVA
must always be used in combination with other antiretroviral drugs. Patients
should be advised to take SUSTIVA on an empty stomach, preferably at bedtime.
Taking SUSTIVA with food increases efavirenz concentrations and may increase
the frequency of adverse reactions. Dosing at bedtime may improve the tolerability
of nervous system symptoms [see DOSAGE AND ADMINISTRATION
and ADVERSE REACTIONS].
Nervous System Symptoms
Patients should be informed that central nervous system symptoms (NSS) including
dizziness, insomnia, impaired concentration, drowsiness, and abnormal dreams
are commonly reported during the first weeks of therapy with SUSTIVA [see WARNINGS
AND PRECAUTIONS]. Dosing at bedtime may improve the tolerability of these
symptoms, which are likely to improve with continued therapy. Patients should
be alerted to the potential for additive effects when SUSTIVA is used concomitantly
with alcohol or psychoactive drugs. Patients should be instructed that if they
experience NSS they should avoid potentially hazardous tasks such as driving
or operating machinery.
Psychiatric Symptoms
Patients should be informed that serious psychiatric symptoms including severe
depression, suicide attempts, aggressive behavior, delusions, paranoia, and
psychosis-like symptoms have been reported in patients receiving SUSTIVA [see
WARNINGS AND PRECAUTIONS]. If they experience severe psychiatric adverse
experiences they should seek immediate medical evaluation. Patients should be
advised to inform their physician of any history of mental illness or substance abuse.
Rash
Patients should be informed that a common side effect is rash [see WARNINGS
AND PRECAUTIONS]. Rashes usually go away without any change in treatment.
However, since rash may be serious, patients should be advised to contact their
physician promptly if rash occurs.
Reproductive Risk Potential
Women receiving SUSTIVA should be instructed to avoid pregnancy [see WARNINGS
AND PRECAUTIONS]. A reliable form of barrier contraception must always be
used in combination with other methods of contraception, including oral or other
hormonal contraception. Because of the long half-life of efavirenz, use of adequate
contraceptive measures for 12 weeks after discontinuation of SUSTIVA is recommended.
Women should be advised to notify their physician if they become pregnant or
plan to become pregnant while taking SUSTIVA. If this drug is used during the
first trimester of pregnancy, or if the patient becomes pregnant while taking
this drug, she should be apprised of the potential harm to the fetus.
Fat Redistribution
Patients should be informed that redistribution or accumulation of body fat
may occur in patients receiving antiretroviral therapy and that the cause and
long-term health effects of these conditionsare not known [see WARNINGS AND
PRECAUTIONS].
Nonclinical Toxicology
Carcinogenesis, Mutagenesis, Impairment of Fertility
Long-term carcinogenicity studies in mice and rats were carried out with efavirenz.
Mice were dosed with 0, 25, 75, 150, or 300 mg/kg/day for 2 years. Incidences
of hepatocellular adenomas and carcinomas and pulmonary alveolar/bronchiolar
adenomas were increased above background in females. No increases in tumor incidence
above background were seen in males. In studies in which rats were administered
efavirenz at doses of 0, 25, 50, or 100 mg/kg/day for 2 years, no increases
in tumor incidence above background were observed. The systemic exposure (based
on AUCs) in mice was approximately 1.7-fold that in humans receiving the 600-mg/day
dose. The exposure in rats was lower than that in humans. The mechanism of the
carcinogenic potential is unknown. However, in genetic toxicology assays, efavirenz
showed no evidence of mutagenic or clastogenic activity in a battery of in
vitro and in vivo studies. These included bacterial mutation assays
in S. typhimurium and E. coli, mammalian mutation assays in Chinese
hamster ovary cells, chromosome aberration assays in human peripheral blood
lymphocytes or Chinese hamster ovary cells, and an in vivo mouse bone
marrow micronucleus assay. Given the lack of genotoxic activity of efavirenz,
the relevance to humans of neoplasms in efavirenz-treated mice is not known.
Efavirenz did not impair mating or fertility of male or female rats, and did not affect sperm of treated male rats. The reproductive performance of offspring born to female rats given efavirenz was not affected. As a result of the rapid clearance of efavirenz in rats, systemic drug exposures achieved in these studies were equivalent to or below those achieved in humans given therapeutic doses of efavirenz.
Use In Specific Populations
Pregnancy
Pregnancy Category D: See WARNINGS AND PRECAUTIONS.
Nursing Mothers
The Centers for Disease Control and Prevention recommend that HIV-infected mothers not breast-feed their infants to avoid risking postnatal transmission of HIV. Although it is not known if efavirenz is secreted in human milk, efavirenz is secreted into the milk of lactating rats. Because of the potential for HIV transmission and the potential for serious adverse effects in nursing infants, mothers should be instructed not to breast-feed if they are receiving SUSTIVA.
Pediatric Use
ACTG 382 is an ongoing, open-label study in 57 NRTI-experienced pediatric patients
to characterize the safety, pharmacokinetics, and antiviral activity of SUSTIVA
in combination with nelfinavir (20-30 mg/kg three times daily) and NRTIs. Mean
age was 8 years (range 3-16). SUSTIVA has not been studied in pediatric patients
below 3 years of age or who weigh less than 13 kg. At 48 weeks, the type and
frequency of adverse experiences was generally similar to that of adult patients
with the exception of a higher incidence of rash, which was reported in 46%
(26/57) of pediatric patients compared to 26% of adults, and a higher frequency
of Grade 3 or 4 rash reported in 5% (3/57) of pediatric patients compared to
0.9% of adults [see WARNINGS AND PRECAUTIONS and ADVERSE
REACTIONS, Table 5].
The starting dose of SUSTIVA was 600 mg once daily adjusted to body size, based
on weight, targeting AUC levels in the range of 190-380 µM•h [see
DOSAGE AND ADMINISTRATION]. The pharmacokinetics of efavirenz in pediatric
patients were similar to the pharmacokinetics in adults who received 600-mg
daily doses of SUSTIVA. In 48 pediatric patients receiving the equivalent of
a 600-mg dose of SUSTIVA, steady-state Cmax was 14.2 ± 5.8 uM (mean ±
SD), steady-state Cmin was 5.6 ± 4.1 µM, and AUC was 218 ±
104 µM•h.
Geriatric Use
Clinical studies of SUSTIVA did not include sufficient numbers of subjects aged 65 years and over to determine whether they respond differently from younger subjects. In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function and of concomitant disease or other therapy.
Hepatic Impairment
The pharmacokinetics of efavirenz have not been adequately studied in patients
with hepatic impairment. Because of the extensive cytochrome P450-mediated metabolism
of efavirenz and limited clinical experience in patients with hepatic impairment,
caution should be exercised in administering SUSTIVA to these patients [see
WARNINGS AND PRECAUTIONS].
Last updated on RxList: 10/14/2009