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Dosage Adjustments for ARV-ARV Drug Interactions
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Many antiretroviral medications used to treat HIV infection, particularly certain protease inhibitors and nonnucleoside reverse transcriptase inhibitors, interact with other antiretroviral agents. These interactions are usually due to effects on hepatic drug metabolism and can cause clinically significant alterations in serum drug concentrations. Certain antiretroviral agents require dosage adjustment (or pharmacokinetic enhancement) when coadministered, and some combinations are contraindicated. This table shows evidence-based adult dosage adjustments for interacting antiretroviral medications. Not all are approved by the U.S. Food and Drug Administration.

For further information, see the Database of Antiretroviral Drug Interactions. For information about pharmacokinetic enhancement ("boosting") of protease inhibitors by ritonavir, see Dosing for Ritonavir-Boosted Protease Inhibitors.

DrugCoadministered DrugDosage Adjustment

Abbreviations: ARV = antiretroviral; BID = 2 times daily; LFTs = liver function tests; PI = protease inhibitor; Q8H = every 8 hours; QD = once daily; TID = 3 times daily

AtazanavirEfavirenz
  • Treatment-naive patients: Atazanavir 400 mg QD + ritonavir 100 mg QD; efavirenz 600 mg QD

  • Treatment-experienced patients: Not recommended

Etravirine
  • Do not coadminister

Nevirapine
  • Do not coadminister

Maraviroc
  • Atazanavir 300 mg QD + ritonavir 100 mg QD; maraviroc 150 mg BID

OR
  • Atazanavir 400 mg QD; maraviroc 150 mg BID

Saquinavir
  • Dosage adjustment not established; consider atazanavir 300 mg QD + ritonavir 100 mg QD; saquinavir 1,600-2,000 mg QD

Tenofovir
  • Atazanavir 300 mg QD + ritonavir 100 mg QD; tenofovir 300 mg QD (atazanavir 400 mg QD + ritonavir 100 mg QD if used concurrently with tenofovir and an H2 receptor antagonist)

Tipranavir
  • Not recommended

DarunavirEtravirine
  • Darunavir 600 mg BID + ritonavir 100 mg BID; etravirine 200 mg BID (dosage adjustment not necessary)

Maraviroc
  • Darunavir 600 mg BID + ritonavir 100 mg BID; mariviroc 150 mg BID

DelavirdineIndinavir
  • Delavirdine 400 mg TID; indinavir 600 mg Q8H

Saquinavir
  • Delavirdine 400 mg TID; saquinavir 800 mg TID (monitor LFTs)

DidanosineTenofovir
  • For body weight ≥60 kg, didanosine 250 mg QD; tenofovir 300 mg QD

  • For body weight <60 kg, didanosine 200 mg QD; tenofovir 300 mg QD

EfavirenzAtazanavir
  • Treatment-naive patients: Atazanavir 400 mg QD + ritonavir 100 mg QD; efavirenz 600 mg QD

  • Treatment-experienced patients: Do not coadminister.

Fosamprenavir
  • Efavirenz 600 mg QD; fosamprenavir 700 mg BID + ritonavir 100 mg BID

OR
  • Efavirenz 600 mg QD; fosamprenavir 1,400 mg QD + ritonavir 300 mg QD (QD dosing of fosamprenavir is not recommended for PI-experienced patients)

Indinavir
  • Efavirenz 600 mg QD; indinavir 800-1,000 mg BID + ritonavir 100-200 mg BID

Lopinavir/ritonavir
  • Efavirenz 600 mg QD; lopinavir/ritonavir 500/125 mg BID

Maraviroc
  • Efavirenz 600 mg QD; maraviroc 600 mg BID

Saquinavir
  • Dosage adjustment of saquinavir not established; consider efavirenz 600 mg QD; saquinavir 1,000 mg BID + ritonavir 200 mg BID

Tipranavir
  • Dosage adjustment not necessary

Elvitegravir/cobicistat (coformulation)Protease inhibitors
NNRTIs
  • Do not coadminister

Maraviroc
  • No data

EtravirineAtazanavir
  • Do not coadminister

Darunavir
  • Etravirine 200 mg BID; darunavir 600 mg BID + ritonavir 100 mg BID (dosage adjustment not necessary)

Lopinavir/ritonavir
  • No dosage adjustment appears to be necessary

Saquinavir
  • Dosage adjustment not established; consider etravirine 200 mg BID; saquinavir 1000 mg BID + ritonavir 100 mg BID

All other PIs
  • Do not coadminister

Maraviroc
  • Etravirine 200 mg BID; maraviroc 600 mg BID (if ETV is given with MVC + DRV-r or other compatible RTV-boosted PI, reduce MVC dosage to 150 mg BID)

FosamprenavirEfavirenz
  • Fosamprenavir 700 mg BID + ritonavir 100 mg BID; efavirenz 600 mg QD

OR
  • Fosamprenavir 1,400 mg QD + ritonavir 300 mg QD; efavirenz 600 mg QD (QD dosing of fosamprenavir is not recommended for PI-experienced patients)

Etravirine
  • Dosage adjustment not established; do not coadminister

Lopinavir/ritonavir
  • Fosamprenavir 1,400 mg BID; lopinavir/ritonavir 500/125 mg BID

Maraviroc
  • Fosamprenavir 1,400 mg BID; maraviroc 150 mg BID

OR
  • Fosamprenavir 700 mg BID + ritonavir 100 mg BID; maraviroc 150 mg BID

OR
  • Fosamprenavir 1,400 mg QD + ritonavir 200 mg QD; maraviroc 150 mg BID

Nevirapine
  • Dosage adjustment of fosamprenavir not established; consider fosamprenavir 700 mg BID + ritonavir 100 mg BID; nevirapine 200 mg BID

OR
  • Fosamprenavir 1,400 mg QD + ritonavir 300 mg QD; nevirapine 200 mg BID (QD dosing of fosamprenavir is not recommended for PI-experienced patients)

Saquinavir
  • Dosage adjustment not established; consider fosamprenavir 700 mg BID + ritonavir 100-200 mg BID; saquinavir 1,000 mg BID

Tipranavir
  • Not recommended

IndinavirDelavirdine
  • Indinavir 600 mg Q8H; delavirdine 400 mg TID

Efavirenz
  • Indinavir 800-1,000 mg BID + ritonavir 100-200 mg BID; efavirenz 600 mg QD

Etravirine
  • Do not coadminister

Lopinavir/ritonavir
  • Indinavir 600-800 mg BID; lopinavir/ritonavir 400/100 mg (2 tablets) BID

Maraviroc
  • Indinavir 800 mg BID + ritonavir 100 mg BID; maraviroc 150 mg BID

OR
  • Indinavir 800 mg Q8H; maraviroc 150 mg BID

Nelfinavir
  • Indinavir 1,200 mg BID; nelfinavir 1,250 mg BID

Nevirapine
  • Consider indinavir 800-1,000 mg BID + ritonavir 100-200 mg BID; nevirapine 200 mg BID

Tipranavir
  • Not recommended

Lopinavir/ritonavirEfavirenz
  • Lopinavir/ritonavir 500/125 mg BID (for ARV-naive patients) or 600/150 BID

  • Lopinavir/ritonavir should not be given QD in patients taking efavirenz

Etravirine
  • No dosage adjustment appears to be necessary

Fosamprenavir
  • Lopinavir/ritonavir 500/125 mg BID; fosamprenavir 1,400 mg BID

Indinavir
  • Lopinavir/ritonavir 400/100 mg BID; indinavir 600-800 mg BID

Maraviroc
  • Lopinavir/ritonavir 400/100 mg BID; maraviroc 150 mg BID

Nevirapine
  • Lopinavir/ritonavir 500/125 mg BID; nevirapine 200 mg BID

  • Lopinavir/ritonavir should not be given QD in patients taking nevirapine

Rilpivirine
  • Dosage adjustment not necessary

Saquinavir
  • Lopinavir/ritonavir 400/100 mg BID; saquinavir 1,000 mg BID

Tipranavir
  • Not recommended

MaravirocAmprenavir
Atazanavir
Darunavir
Fosamprenavir
Indinavir
Lopinavir/ritonavir
Saquinavir
  • Maraviroc 150 mg BID; PI at usual dosage

Efavirenz
Etravirine
(if used without PIs listed above or other strong CYP3A inhibitor)
  • Maraviroc 600 mg BID, efavirenz 600 mg QD

  • Maraviroc 600 mg BID, etravirine 200 mg BID

Nevirapine
  • Maraviroc 300 mg BID (dosage adjustment not necessary); nevirapine 200 mg BID

Rilpivirine
  • No data

Tipranavir
  • Maraviroc 300 mg BID (dosage adjustment not necessary); tipranavir 500 mg BID + ritonavir 200 mg BID

NelfinavirIndinavir
  • Nelfinavir 1,250 mg BID; indinavir 1,200 mg BID

Etravirine
  • Do not coadminister

Maraviroc
  • Nelfinavir 1,250 mg BID; maraviroc 150 mg BID

NevirapineAtazanavir
  • Do not coadminister

Fosamprenavir
  • Dosage adjustment of fosamprenavir not established; consider nevirapine 200 mg BID; fosamprenavir 700 mg BID + ritonavir 100 mg BID

OR
  • Nevirapine 200 mg BID; fosamprenavir 1,400 mg QD + ritonavir 300 mg QD (QD dosing of fosamprenavir is not recommended for PI-experienced patients)

Indinavir
  • Consider nevirapine 200 mg BID; indinavir 800-1,000 mg BID + ritonavir 100-200 mg BID

Lopinavir/ritonavir
  • Nevirapine 200 mg BID; lopinavir/ritonavir 500/125 mg BID

Maraviroc
  • Nevirapine 200 mg BID; maraviroc 300 mg BID (dosage adjustment not necessary)

Saquinavir
  • Dosage adjustment of saquinavir not established; consider nevirapine 200 mg BID; saquinavir 400 mg BID + ritonavir 400 mg BID

Tipranavir
  • Dosage adjustment not established

RilpivirineProtease inhibitors
  • Dosage adjustment does not appear to be necessary

Maraviroc
  • No data

Elvitegravir/cobicistat
  • No data

SaquinavirAtazanavir
  • Dosage adjustment not established; consider saquinavir 1,600-2,000 mg QD + atazanavir 300 mg QD + ritonavir 100 mg QD

Delavirdine
  • Saquinavir 800 mg TID; delavirdine 400 mg TID (monitor LFTs)

Efavirenz
  • Dosage adjustment of saquinavir not established; consider saquinavir 1,000 mg BID + ritonavir 200 mg BID; efavirenz 600 mg QD

Etravirine
  • Saquinavir 1000 mg BID + ritonavir 100 mg BID; etravirine 200 mg BID

Fosamprenavir
  • Dosage adjustment not established; consider saquinavir 1,000 mg BID + ritonavir 100-200 mg BID; fosamprenavir 700 mg BID

Lopinavir/ritonavir
  • Saquinavir 1,000 mg BID; lopinavir/ritonavir 400/100 mg (2 tablets) BID

Maraviroc
  • Saquinavir 1,000 mg BID + ritonavir 100-200 mg BID; maraviroc 150 mg BID

Nevirapine
  • Dosage adjustment of saquinavir not established; consider saquinavir 400 mg BID + ritonavir 400 mg BID; nevirapine 200 mg BID

Tipranavir
  • Not recommended

TenofovirAtazanavir
  • Tenofovir 300 mg QD; atazanavir 300 mg QD + ritonavir 100 mg QD (atazanavir 400 mg QD + ritonavir 100 mg QD if used concurrently with tenofovir and an H2 receptor antagonist)

Didanosine
  • Tenofovir 300 mg QD; didanosine 250 mg QD (for body weight ≥60 kg)

  • Tenofovir 300 mg QD; didanosine 200 mg QD (for body weight <60 kg)

TipranavirAtazanavir
Darunavir
Fosamprenavir
Lopinavir/ritonavir
Saquinavir
  • Combination of tipranavir and other PIs is not currently recommended

Efavirenz
Nevirapine
Rilpivirine
  • Dosage adjustment not necessary

Etravirine
  • Do not coadminister

Maraviroc
  • Tipranavir 500 mg BID + ritonavir 200 mg BID; maraviroc 300 mg BID (dosage adjustment not necessary)

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