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New ARV Interactions (September 2010-March 2011)

for Health Care Providers

New ARV Interactions (September 2010-March 2011)

Back to Updates to the Database of ARV Drug Interactions

Drug OneDrug TwoClinical EffectsMechanismsManagement
Source: McNicholl I. HIV InSite Database of Antiretroviral Drug InteractionsLink will take you outside the VA website. VA is not responsible for the content of the linked site.. University of California San Francisco: Center for HIV Information; 2011.
AtazanavirPitavastatinPossibly ↑ pitavastatin effects Start 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
DarunavirBuprenorphine Inhibition 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 effects No 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 period Avoid 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)
Maraviroc Induction of CYP450 3A4 by etravirine↑ maraviroc to 600 mg BID when used with etravirine
FosamprenavirParoxetine↓ paroxetine effects Titrate paroxetine to effect
FosamprenavirRosuvastatin No dosage adjustment necessary
IndinavirAtovaquone No dosage adjustment necessary
Lopinavir/ritonavirBupropion↑ bupropion effectsPossible induction of CYP450 2B6 and UGT enzymes
Lopinavir/ritonavirEchinacea No dosage adjustment necessary
Lopinavir/ritonavirKetoconazole↑ ketoconazole effects; ↓ lopinavir/ritonavir effects Manufacturer recommends against using high dosages of ketoconazole (>200 mg daily)

Alternative agents: fluconazole
Lopinavir/ritonavirRosuvastatin↑ rosuvastatin effects Do not coadminister

Alternative agents: pravastatin, atorvastatin
MaravirocRaltegravir No dosage adjustment necessary
RaltegravirAntacids No 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

From New ARV Interactions (September 2010-March 2011)
HIV Meds Quarterly Research Brief
HIV Meds Quarterly, Spring 2011