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Dosing for Ritonavir-Boosted Protease Inhibitors
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Ritonavir, a potent inhibitor of cytochrome P450 3A4 (CYP3A4) and CYP2D6, can cause clinically significant increases in serum levels of other protease inhibitors (PIs). Pharmacokinetic enhancement of certain PIs with low-dose ritonavir can increase drug concentrations of these PIs while allowing a reduction in pill burden, dosing frequency, and food restrictions.

The following table shows evidence-based possibilities for adult dosages of ritonavir-boosted PIs. Not all are approved by the U.S. Food and Drug Administration.

For more information, see the Database of Antiretroviral Drug Interactions.

Protease InhibitorAdult Dosing Options

Abbreviations: BID = 2 times per day; QD = once daily

* When used in combination with efavirenz or nevirapine, may require dosage adjustment. See Dosage Adjustments for ARV-ARV Drug Interactions.

# Once-daily dosing of darunavir, fosamprenavir, lopinavir, or saquinavir is not recommended for PI-experienced patients.

§ Once-daily lopinavir/ritonavir should not be used in combination with efavirenz, nevirapine, amprenavir, fosamprenavir, or nelfinavir (dosage adjustment not established). Once-daily dosing of lopinavir/ritonavir should not be used for pregnant women, patients receiving hemodialysis, or patients with ≥3 mutations associated with resistance to lopinavir/ritonavir.

** When used in combination with efavirenz; when used in combination with tenofovir and an H2 receptor antagonist.

AtazanavirAtazanavir 300 mg QD + ritonavir 100 mg QD
Atazanavir 400 mg QD + ritonavir 100 mg QD**
DarunavirDarunavir 600 mg BID + ritonavir 100 mg BID
Darunavir 800 mg QD + ritonavir 100 mg QD #
FosamprenavirFosamprenavir 700 mg BID + ritonavir 100 mg BID*
Fosamprenavir 1,400 mg QD + ritonavir 200 mg QD* #
Fosamprenavir 1,400 mg QD + ritonavir 100 mg QD* #
IndinavirIndinavir 800 mg BID + ritonavir 100 mg BID*
Indinavir 800 mg BID + ritonavir 200 mg BID*
Indinavir 400 mg BID + ritonavir 400 mg BID*
LopinavirLopinavir 400 mg + ritonavir 100 mg BID (coformulated as Kaletra)*
Lopinavir 800 mg + ritonavir 200 mg QD (coformulated as Kaletra)# §
SaquinavirSaquinavir 1,000 mg BID + ritonavir 100 mg BID
Saquinavir 1,600 mg QD + ritonavir 100 mg QD#
Saquinavir 400 mg BID + ritonavir 400 mg BID
TipranavirTipranavir 500 mg BID + ritonavir 200 mg BID
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