| HIV antiviral agents |
Protease inhibitor: Fosamprenavir calcium | ↓ amprenavir | Fosamprenavir
(unboosted): Appropriate doses of the combinations with respect to safety
and efficacy have not been established. Fosamprenavir/ritonavir:
An additional 100 mg/day (300 mg total) of ritonavir is recommended when 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 sulfate | ↓ 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. When indinavir at an increased dose (1000 mg
every 8 hours) was given with SUSTIVA (600 mg once daily), the indinavir AUC
and Cmin were decreased on average by 33-46% and 39-57%,
respectively, compared to when indinavir (800 mg every 8 hours) was given
alone. |
Protease inhibitor: Lopinavir/ritonavir | ↓ lopinavir* | Lopinavir/ritonavir
tablets should not be administered once daily in combination with SUSTIVA.
In antiretroviral-naive patients, lopinavir/ritonavir tablets can be used
twice daily in combination with SUSTIVA with no dose adjustment. A dose increase
of lopinavir/ritonavir tablets to 600/150 mg (3 tablets) twice daily may be
considered when used in combination with SUSTIVA in treatment-experienced
patients where decreased susceptibility to lopinavir is clinically suspected
(by treatment history or laboratory evidence). A dose increase of lopinavir/ritonavir
oral solution to 533/133 mg (6.5 mL) twice daily taken with food is recommended
when used in combination with SUSTIVA. |
Protease inhibitor: Ritonavir | ↑ ritonavir* ↑ efavirenz* | When ritonavir
500 mg q12h was coadministered with SUSTIVA 600 mg once daily, the combination
was associated with a higher frequency of adverse clinical experiences (eg,
dizziness, nausea, paresthesia) and laboratory abnormalities (elevated liver
enzymes). Monitoring of liver enzymes is recommended when SUSTIVA is used
in combination with ritonavir. |
Protease inhibitor: Saquinavir | ↓ saquinavir* | Should not be used as sole protease inhibitor in combination with SUSTIVA. |
NNRTI: Other NNRTIs | ↑ or ↓ efavirenz and/or NNRTI
| Combining 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. |
Integrase strand transfer inhibitor: Raltegravir | ↓ raltegravir* | SUSTIVA reduces plasma concentrations of raltegravir. The clinical significance of this interaction has not been directly assessed.
|
| Hepatitis C antiviral agents |
Protease inhibitor: Boceprevir | ↓ boceprevir* | Plasma trough concentrations of boceprevir were decreased when boceprevir was coadministered with SUSTIVA, which may result in loss of therapeutic effect. The combination should be avoided.
|
Protease inhibitor: Telaprevir | ↓ telaprevir* ↓ efavirenz* | Concomitant administration of telaprevir and SUSTIVA resulted in reduced steady-state exposures to telaprevir and efavirenz.
|
| Other agents |
Anticoagulant: Warfarin | ↑ or ↓ warfarin | Plasma concentrations
and effects potentially increased or decreased by SUSTIVA. |
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 | ↓ bupropion* | The effect of efavirenz on bupropion exposure is thought to be due to the induction of bupropion metabolism. Increases in bupropion dosage should be guided by clinical response, but the maximum recommended dose of bupropion should not be exceeded. |
| Sertraline | ↓ sertraline* | Increases in sertraline
dosage should be guided by clinical response. |
Antifungals: Voriconazole | ↓ voriconazole* ↑ efavirenz* | SUSTIVA and voriconazole
must not be coadministered at standard doses. Efavirenz significantly decreases
voriconazole plasma concentrations, and coadministration may decrease the
therapeutic effectiveness of voriconazole. Also, voriconazole significantly
increases efavirenz plasma concentrations, which may increase the risk of
SUSTIVA-associated side effects. 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 should not be broken. [See Dosage
and Administration (2.1) and Clinical
Pharmacology (12.3, Tables 8 and 9).] |
Itraconazole | ↓ itraconazole* ↓ hydroxyitraconazole* | Since no dose recommendation
for itraconazole can be made, alternative antifungal treatment should be considered. |
| Ketoconazole | ↓ ketoconazole | Drug interaction
studies with SUSTIVA and ketoconazole have not been conducted. SUSTIVA has
the potential to decrease plasma concentrations of ketoconazole. |
| Posaconazole | ↓ posaconazole* | Avoid concomitant use unless the benefit outweighs the risks.
|
Anti-infective: Clarithromycin | ↓ clarithromycin* ↑ 14-OH
metabolite* | Plasma concentrations
decreased by SUSTIVA; clinical significance unknown. In uninfected volunteers,
46% developed rash while receiving SUSTIVA and clarithromycin. No dose adjustment
of SUSTIVA is recommended when given with clarithromycin. Alternatives to
clarithromycin, such as azithromycin, should be considered (see Other Drugs, following table). Other
macrolide antibiotics, such as erythromycin, have not been studied in combination
with SUSTIVA. |
Antimycobacterials: Rifabutin | ↓ rifabutin* | Increase daily dose of rifabutin
by 50%. Consider doubling the rifabutin dose in regimens where rifabutin is
given 2 or 3 times a week. |
| Rifampin | ↓ efavirenz* | If SUSTIVA is coadministered with rifampin to patients weighing 50 kg or more, an increase in the dose of SUSTIVA to 800 mg once daily is recommended. |
Calcium channel blockers: Diltiazem | ↓ diltiazem* ↓ desacetyl diltiazem* ↓ N-monodesmethyl diltiazem* | 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. |
| Others (eg, felodipine,
nicardipine, nifedipine, verapamil) | ↓ calcium
channel blocker | No data are available
on the potential interactions of efavirenz with other calcium channel blockers
that are substrates of CYP3A. The potential exists for reduction in plasma
concentrations of the calcium channel blocker. Dose adjustments 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 | ↓ active metabolites of norgestimate* | A reliable method of barrier contraception must be used in addition to hormonal contraceptives. Efavirenz had no effect on ethinyl estradiol concentrations, but progestin levels (norelgestromin and levonorgestrel) were markedly decreased. No effect of ethinyl estradiol/norgestimate on efavirenz plasma concentrations was observed.
|
Implant Etonogestrel | ↓ etonogestrel | A reliable method of barrier contraception must be used in addition to hormonal contraceptives. The interaction between etonogestrel and efavirenz has not been studied. 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 | ↓ immunosuppressant
| Decreased exposure of the immunosuppressant may be expected due to CYP3A induction. These immunosuppressants are not anticipated to affect exposure of efavirenz. Dose 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* | Coadministration
in HIV-infected individuals with a history of injection drug use resulted
in decreased plasma levels of methadone and signs of opiate withdrawal. Methadone
dose was increased by a mean of 22% to alleviate withdrawal symptoms. Patients
should be monitored for signs of withdrawal and their methadone dose increased
as required to alleviate withdrawal symptoms. |