Dosage Adjustments for ARV-ARV Drug Interactions (Adult Dosing)

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 .

Drug Coadministered Drug Dosage Adjustment Amprenavir As of June 2005, no longer manufactured for adult dosing; consider fosamprenavir. Atazanavir Efavirenz Atazanavir 300 mg QD + ritonavir 100 mg QD; efavirenz 600 mg QD Nevirapine Dosage adjustment of atazanavir not established; consider atazanavir 300 mg QD + ritonavir 100 mg QD; nevirapine 200 mg BID 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 Tipranavir Not recommended Delavirdine Indinavir Delavirdine 400 mg TID; indinavir 600 mg Q8H Saquinavir Delavirdine 400 mg TID; saquinavir 800 mg TID (monitor LFTs) Didanosine Tenofovir 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 Efavirenz Atazanavir Efavirenz 600 mg QD; atazanavir 300 mg QD + ritonavir 100 mg QD 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 protease inhibitor-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 400/100 mg (2 tablets) BID (for ARV-naive patients) or 600/150 (3 tablets) BID (for ARV-experienced patients) 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 Fosamprenavir Efavirenz 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 protease inhibitor-experienced patients) Lopinavir/ritonavir Dosage adjustment of fosamprenavir and lopinavir/ritonavir not established; consider fosamprenavir 1,400 mg BID; lopinavir/ritonavir 600/150 mg (3 tablets) 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 protease inhibitor-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 Indinavir Delavirdine Indinavir 600 mg Q8H; delavirdine 400 mg TID Efavirenz Indinavir 800-1,000 mg BID + ritonavir 100-200 mg BID; efavirenz 600 mg QD 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/ritonavir Efavirenz Lopinavir/ritonavir 400/100 mg (2 tablets) BID (for ARV-naive patients) or 600/150 (3 tablets) BID (for ARV-experienced patients); efavirenz 600 mg QD Fosamprenavir Dosage adjustment of fosamprenavir and lopinavir/ritonavir not established; consider lopinavir/ritonavir 600/150 mg (3 tablets) BID; fosamprenavir 1,400 mg BID Indinavir Lopinavir/ritonavir 400/100 mg (2 tablets) BID; indinavir 600-800 mg BID Maraviroc Lopinavir/ritonavir 400/100 mg (2 tablets) BID; maraviroc 150 mg BID Nevirapine Lopinavir/ritonavir 400/100 mg (2 tablets) BID (ARV-naive patients) or 600/150 (3 tablets) BID (for ARV-experienced patients); nevirapine 200 mg BID Saquinavir Lopinavir/ritonavir 400/100 mg (2 tablets) BID; saquinavir 1,000 mg BID Tipranavir Not recommended Maraviroc Amprenavir Atazanavir Darunavir Fosamprenavir Indinavir Lopinavir/ritonavir Saquinavir Maraviroc 150 mg BID; protease inhibitor at usual dose Efavirenz Etravirine (if used without PIs listed above or other strong CYP3A inhibitor) Maraviroc 600 mg BID, efavirenz 600 mg QD Nevirapine Maraviroc 300 mg BID (dosage adjustment not necessary); nevirapine 200 mg BID Tipranavir Maraviroc 300 mg BID (dosage adjustment not necessary); tipranavir 500 mg BID + ritonavir 200 mg BID Nelfinavir Indinavir Nelfinavir 1,250 mg BID; indinavir 1,200 mg BID Maraviroc Nelfinavir 1,250 mg BID; maraviroc 150 mg BID Nevirapine Atazanavir Dosage adjustment of atazanavir not studied; consider nevirapine 200 mg BID; atazanavir 300 mg QD + ritonavir 100 mg QD 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 protease inhibitor-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 400/100 mg (2 tablets) BID (for ARV-naive patients), 600/150 mg (3 tablets) BID (for ARV-experienced patients) 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 Saquinavir Atazanavir 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 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 Tenofovir Atazanavir Tenofovir 300 mg QD; atazanavir 300 mg QD + ritonavir 100 mg QD 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) Tipranavir Atazanavir Fosamprenavir Lopinavir/ritonavir Saquinavir Combination of tipranavir and other protease inhibitors is not currently recommended Maraviroc Tipranavir 500 mg BID + ritonavir 200 mg BID; maraviroc 300 mg BID (dosage adjustment not necessary) Efavirenz Nevirapine Dosage adjustment not necessary

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

Copyright 2008, the AIDS Education & Training Centers National Resource Center, unless otherwise noted. All rights reserved. Email webmaster@aidsetc.org with questions, comments, or problems. See disclaimer for usage guidelines.