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Home > Treatment > HIV Meds Quarterly > Winter/Spring 2011 > 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 (September 2010-March 2011)
Drug OneDrug TwoClinical EffectsMechanismsManagement
Source: McNicholl I. HIV InSite Database of Antiretroviral Drug Interactions. University of California San Francisco: Center for HIV Information; 2011.
AtazanavirPitavastatinPossibly ↑ pitavastatin effectsStart at lowest dosage and titrate to effect
Atazanavir
(atazanavir 300 mg QD with ritonavir 100 mg QD)
Rosuvastatin↑ rosuvastatin effectsDo not coadminister

Alternative agents:
pravastatin, atorvastatin
DarunavirBuprenorphineInhibition of CYP450 3A4 by darunavir/ritonavirNo dosage adjustment necessary
DarunavirMethadoneMay ↓ methadone effects (eg, withdrawal)Monitor for signs and symptoms of methadone withdrawal; some patients may need ↑ in the methadone dosage
DarunavirNevirapinePossibly ↑ darunavir effects; possibly ↑ nevirapine effectsNo dosage adjustment necessary
DarunavirRifabutin↑ darunavir and rifabutin effectsInhibition of CYP450 3A4 by darunavir↓ rifabutin dosage to 150 mg QOD when combined with darunavir/ritonavir
DarunavirRosuvastatinNo change in lipid-lowering ability within 35-day study periodAvoid coadministration if possible; if used, use caution and start at 5 mg daily
Efavirenz
(400 mg QD)
Proguanil
(300 mg, single dose)
Possibly ↓ antimalarial effectsPossible inhibition of CYP450 2C19 by efavirenz; possible induction of P-gp by efavirenzDosage adjustment not established
Efavirenz
(600 mg QHS)
Proguanil
(100 mg with 250 mg atovaquone, single dose)
↑ atovaquone glucuronidation; induction of CYP450 3A4 by efavirenzDosage adjustment not established
Etravirine
(200 mg BID with darunavir/ritonavir 600/100 mg BID)
Maraviroc↑ maraviroc effectsInhibition of CYP450 3A4 by darunavir/ritonavir↓ maraviroc to 150 mg BID
Etravirine
(200 mg BID)
MaravirocInduction of CYP450 3A4 by etravirine↑ maraviroc to 600 mg BID when used with etravirine
FosamprenavirParoxetine↓ paroxetine effectsTitrate paroxetine to effect
FosamprenavirRosuvastatinNo dosage adjustment necessary
IndinavirAtovaquoneNo dosage adjustment necessary
Lopinavir/ritonavirBupropion↑ bupropion effectsPossible induction of CYP450 2B6 and UGT enzymes
Lopinavir/ritonavirEchinaceaNo dosage adjustment necessary
Lopinavir/ritonavirKetoconazole↑ ketoconazole effects; ↓ lopinavir/ritonavir effectsManufacturer recommends against using high dosages of ketoconazole (>200 mg daily)

Alternative agents: fluconazole
Lopinavir/ritonavirRosuvastatin↑ rosuvastatin effectsDo not coadminister

Alternative agents: pravastatin, atorvastatin
MaravirocRaltegravirNo dosage adjustment necessary
RaltegravirAntacidsNo dosage adjustment necessary
RitonavirColchicine↑ colchicine effectsInhibition of CYP450 3A4 by ritonavirFor treatment of gout, ↓ colchicine dosage to 0.6 mg for a single dose, then 0.3 mg 1 hour later; dose not to be repeated earlier than 3 days; for prophylaxis of gout, ↓ colchicine dosage to 0.3 mg QD if on 0.6 mg BID prior to PI therapy or ↓ colchicine dosage to 0.3 mg QOD if on 0.6 mg QD prior to PI therapy
Ritonavir
(200 mg BID)
Tadalafil↑ tadalafil effects (eg, hypotension, priapism)Inhibition of CYP450 3A4 by ritonavirDo not exceed 10 mg tadalafil every 72 hours
Ritonavir
(500 mg or 600 mg BID)
Tadalafil↑ tadalafil effects (eg, hypotension, priapism)Inhibition of CYP450 3A4 by ritonavirDo not exceed 10 mg tadalafil every 72 hours
ZidovudineAtovaquone ↑ zidovudine effectsInhibition of glucuronidation by atovaquoneNo dosage adjustment necessary

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