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Home > Treatment > HIV Meds Quarterly > Spring 2008 > ETV: ARV Interactions
Etravirine: ARV Interactions

Etravirine, a nonnucleoside reverse transcriptase inhibitor (NNRTI) approved by the U.S. Food and Drug Administration in January 2008, is active against many HIV strains that are resistant to first-generation NNRTIs. It is likely to play an important role in the treatment of individuals with NNRTI resistance mutations. Etravirine, however, has therapeutically significant interactions with many other antiretroviral (ARV) drugs, and with other medications, that may substantially affect the efficacy or toxicity of an ARV regimen that contains etravirine. It is important to consider these potential pharmacokinetic interactions when selecting the other agents that will accompany etravirine in the ARV regimen, particularly the protease inhibitors.

Etravirine is a substrate of the cytochrome P450 enzyme system (CYP3A4, CYP2C9, and CYP2C19); it is also an inducer of CYP3A4 and an inhibitor of CYP2C9 and CYP2C19. Etravirine decreases serum concentrations of atazanavir, maraviroc, and raltegravir, and it increases concentrations of fosamprenavir. Etravirine levels are significantly decreased by tipranavir, full-dose ritonavir, efavirenz, and nevirapine. They are modestly decreased by darunavir, saquinavir, and tenofovir, and are increased by lopinavir/ritonavir. These and other interactions are incompletely studied, but based on current information, etravirine should not be given with other NNRTIs, unboosted protease inhibitors, atazanavir/ritonavir, fosamprenavir/ritonavir, or tipranavir/ritonavir. If used with certain other interacting ARVs, dosage adjustment or close monitoring of the patient may be required.

For recommendations on administration of etravirine with other antiretrovirals, see the table below. Note that etravirine also interacts with many nonantiretroviral medications. For information on these, see product label or the HIV InSite Database of Antiretroviral Drug Interactions.

Etravirine Interactions with Other Antiretrovirals
Interacting ARVPharmacokinetic EffectsRecommendations and Comments

Abbreviations: AUC = area under the plasma concentration-time curve; BID = twice daily; Cmax = maximal plasma concentration; Cmin = minimal plasma concentration; ETV = etravirine; PI = protease inhibitor

Color code:

do not coadminister


may be coadministered; no dosage adjustment required

Nucleoside/Nucleotide Analogues
Didanosine (ddI)

ddI: no significant change in levels

ETV: ↑ AUC 11%

Not clinically significant

Tenofovir (TDF)

TDF: ↑ Cmin 19%;
↑ AUC 15%;
↑ Cmax 15%

ETV: ↓ Cmin 18%;
↓ AUC 19%

Not thought to be clinically significant

Nonnucleoside Reverse Transcriptase Inhibitors
Delavirdine (DLV)ETV: anticipate ↑ levels

Do not administer with ETV

Efavirenz (EFV)EFV: anticipate ↓ levels ETV: ↓ AUC 41%

Do not administer with ETV

Nevirapine (NVP)NVP: anticipate ↓ levels ETV: ↓ AUC 55%

Do not administer with ETV

Protease Inhibitors (Unboosted)
Atazanavir (ATV)

ATV: ↓ Cmin 47%;
↓ AUC 17%

ETV: ↑ Cmin 58%;
↑ AUC 50%;
↑ Cmax 47%

ETV should not be used with unboosted PIs

Fosamprenavir (FPV)Not studied; significant ↑ in FPV levels expected
Indinavir (IDV)

IDV: ↓ AUC 46%

ETV: ↑ AUC 51%

Nelfinavir (NFV)Not studied; ↑ NFV levels expected
Ritonavir (RTV) (600 mg BID)ETV: ↓ AUC 46%
Saquinavir (SQV)SQV: ↓ AUC 52%
Protease Inhibitors (Ritonavir Boosted)
Atazanavir (ATV)-r

ATV: ↓ Cmin 38%;
↓ AUC 14%

ETV: ↑ AUC 30%;
↑ Cmax 30%

Do not administer with ETV

Darunavir (DRV)-r

DRV: no significant change in levels

ETV: ↓ Cmin 49%;
↓ AUC 37% (ETV 100 mg BID)

Pharmacokinetic studies of ETV 200 mg + DRV-r versus ETV 200 mg alone have not been conducted; it is not known whether dosage adjustment of ETV is necessary

In clinical studies, regimens containing DRV-r + ETV were more effective than those containing DRV-r without ETV

Fosamprenavir (FPV)-rFPV: ↑ Cmin 77%;
↑ AUC 69%;
↑ Cmax 62%

Dosage adjustment not established; do not administer with ETV

Indinavir (IDV)-rNot studied

Do not administer with ETV

Lopinavir (LPV)-r (Kaletra)

LPV: ↓ Cmin 8%;
↓ AUC 19%

ETV: ↑ Cmin 23%;
↑ AUC 17%;
↑ Cmax 15%

No dosage adjustment appears to be necessary

Saquinavir (SQV)-r

SQV: ↓ Cmin 29%;
↓ AUC 37%

ETV: ↓ Cmin 29%;
↓ AUC 33%

Clinical significance of decreased SQV and ETV levels is unknown; dosage adjustment not established

Tipiranavir (TPV)-r

TPV: ↑ Cmin 24%;
↑ AUC 18%

ETV: ↓ Cmin 82%;
↓ AUC 76%

Do not administer with ETV

Fusion Inhibitors
Enfuvirtide (ENF)Anticipate no significant change in ENF or ETV levels

No dosage adjustment required

Chemokine Coreceptor Antagonists
Maraviroc (MVC)

MVC: ↓ Cmin 29%;
↓ AUC 53%;
↓ Cmax 60%

ETV: no significant change in levels

Dosage adjustment required: ↑ MVC dosage to 600 mg BID (if ETV is given with MVC + DRV-r or other compatible RTV-boosted PI, ↓ MVC dosage to 150 mg BID)

Integrase Inhibitors
Raltegravir (RAL)

RAL: ↓ Cmin 34%;
↓ AUC 10%

ETV: no significant change in levels

Clinical significance of decreased RAL levels is not clear; no information available on dosage adjustment


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