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Home > Treatment > HIV Meds Quarterly > Spring/Summer 2010 > ARV Interactions
Updates to the Database of ARV Drug Interactions
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Updates to the Database of ARV Drug Interactions

The following table summarizes recent additions to the HIV InSite Database of Antiretroviral Drug Interactions. For a full description of the updates, including references to the studies from which the data were derived, go to the database, click on a specific drug name, and search for the interacting agent.

New ARV Interactions (April 2010-August 2010)
Drug OneDrug TwoClinical EffectsMechanismsManagement
Source: McNicholl I. HIV InSite Database of Antiretroviral Drug Interactions. University of California San Francisco: Center for HIV Information; 2010
AtazanavirAtovaquonePotentially compromised antimalarial activity↑ atovaquone glucuronidation; induction of CYP450 3A4 by atazanavir/ritonavirDosage adjustment not established
AtazanavirDarunavirNo dosage adjustment necessary
Atazanavir
(300 mg once daily)
Posaconazole
(400 mg BID)
↑ atazanavir effectsInhibition of CYP450 3A4 by posaconazoleDosage adjustment not established; monitor closely for adverse effects during coadministration
Atazanavir
(300 mg once daily with 100 mg ritonavir once daily)
Posaconazole
(400 mg BID)
↑ atazanavir effectsInhibition of CYP450 3A4 by posaconazoleDosage adjustment not established; monitor closely for adverse effects during coadministration
AtazanavirProguanilPotentially compromised antimalarial activity↑ atovaquone glucuronidation; induction of CYP450 3A4 by atazanavir/ritonavirDosage adjustment not established
AtazanavirRaltegravirDosage adjustment not established
AtazanavirVoriconazole↓ voriconazole effectsPossible induction of CYP450 by ritonavirDo not coadminister
DarunavirRosuvastatinNo change in lipid-lowering ability within 35-day study periodNo dosage adjustment necessary
DarunavirVoriconazole↓ voriconazole effectsPossible induction of CYP450 by ritonavirDo not coadminister
EfavirenzAtovaquonePotentially compromised antimalarial activity↑ atovaquone glucuronidation; induction of CYP450 3A4 by efavirenzDosage adjustment not established
EfavirenzPosaconazole↓ posaconazole effectsInduction of UDP-glucuronosyltransferase (UGT) by efavirenzDosage adjustment not established
EfavirenzProguanil↑ atovaquone glucuronidation; induction of CYP450 3A4 by efavirenzDosage adjustment not established
Efavirenz
(300 mg QHS for 7 days)
Voriconazole
(400 mg Q12H on days 2-7)
No dosage adjustment necessary
Efavirenz
400 mg once daily for 9 days
Voriconazole
(400 mg PO Q12H on day 1, then 200 mg Q12H on days 2-8)
↑ efavirenz effects and ↓ voriconazole effectsInhibition of CYP450 3A4 by voriconazole and induction of CYP450 3A4 by efavirenzDo not coadminister at standard dosages; ↑ voriconazole to 400 mg Q12H and ↓ efavirenz to 300 mg QHS
Efavirenz
(300 mg QHS for 7 days)
Voriconazole
(300 mg Q12H on days 2-7)
↓ voriconazole effectsInduction of CYP450 3A4 by efavirenzDo not coadminister at standard dosages; ↑ voriconazole to 400 mg Q12H and ↓ efavirenz to 300 mg QHS
EtravirineItraconazole↓ itraconazole effects
EtravirinePosaconazole
IndinavirItraconazole↑ indinavir effectsInhibition of CYP450 3A4 by itraconazole↓ indinavir to 600 mg Q8H; do not exceed itraconazole 200 mg BID
IndinavirVoriconazoleNo dosage adjustment necessary
LamivudineChlorpropamidePotentially ↑ serum glucose concentrationsConsider alternative agents:
Glyburide, glipizide, metformin
Lopinavir/ritonavir AtovaquonePotentially compromised antimalarial activity↑ atovaquone glucuronidation; induction of CYP450 3A4 by lopinavir/ritonavirDosage adjustment not established
Lopinavir/ritonavir Bosentan↑ bosentan effectsInhibition of CYP450 3A4 by lopinavir/ritonavirStart low and titrate bosentan to effect
Lopinavir/ritonavir Gemfibrozil↓ gemfibrozil effectsReduced gemfibrozil absorption owing to lopinavir/ritonavirPotential option includes utilizing alternative antiretrovirals; unknown whether fenofibrate has same interaction as gemfibrozil
Lopinavir/ritonavir ProguanilPotentially compromised antimalarial activity↑ atovaquone glucuronidation; induction of CYP450 3A4 by lopinavir/ritonavirDosage adjustment not established
Lopinavir/ritonavirRifampin↓ lopinavir effects at lower dosagesInduction of CYP450 3A4 by rifampinLopinavir/ritonavir dosage of 800/200 mg Q12H appears to compensate for rifampin-induced 3A4 induction
NevirapineChlorpropamide
RaltegravirPravastatinNo dosage adjustment necessary
RitonavirPosaconazolePossibly ↑ ritonavir effectsInhibition of CYP450 3A4 by posaconazole; potential inhibition of UGT 1A1 by atazanavirDosage adjustment not necessary
Ritonavir
(100 mg Q12H for 9 days)
Voriconazole
(400 mg Q12H)
↓ voriconazole effectsInduction of CYP450 3A4 by ritonavirAvoid coadministration; consider use of non-ritonavir-containing antiretroviral regimens
Ritonavir
(400 mg Q12H for 9 days)
Voriconazole
(400 mg Q12H)
↓ voriconazole effectsInduction of CYP450 3A4 by ritonavirDo not coadminister
SaquinavirItraconazole↑ itraconazole effects; ↑ saquinavir effectsInhibition of CYP450 3A4 by itraconazole and saquinavir and ritonavirConsider reducing itraconazole to 100 mg BID
SaquinavirKetoconazole↑ saquinavir effectsInhibition of CYP450 3A4 by ketoconazoleDosage adjustment not established
SaquinavirMethadone↓ methadone effects (eg, withdrawal)Monitor for signs and symptoms of methadone withdrawal; some patients may need ↑ in methadone dosage
StavudineChlorpropamidePotentially ↑ serum glucose concentrationsConsider alternative agents:
Glyburide, glipizide, metformin
TenofovirSaquinavirNo dosage adjustment necessary

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