From the FDA Drug Label
Selected PI(s) in the control arm included: lopinavir in 36%, (fos)amprenavir in 34%, saquinavir in 35% and atazanavir in 17%; 98% of control subjects received a ritonavir boosted PI regimen The individually pre-selected protease inhibitor based on genotypic testing and the subject's medical history was lopinavir in 48.7%, amprenavir in 26.4%, saquinavir in 21.8% and indinavir in 3.1% of subjects.
The list of ritonavir boosted protease inhibitors mentioned in the drug labels includes:
- Lopinavir/ritonavir
- Fosamprenavir/ritonavir
- Saquinavir/ritonavir
- Atazanavir/ritonavir
- Indinavir/ritonavir
- Darunavir/ritonavir
- Tipranavir/ritonavir 1 2
From the Research
Ritonavir-boosted protease inhibitors commonly used in HIV treatment include atazanavir/ritonavir, darunavir/ritonavir, lopinavir/ritonavir, and less frequently used options like tipranavir/ritonavir and saquinavir/ritonavir. These medications work by combining a primary protease inhibitor with low-dose ritonavir (typically 100-200mg), which inhibits the CYP3A4 enzyme that metabolizes the primary drug, thereby increasing its blood levels and allowing for less frequent dosing 3. The choice of ritonavir-boosted protease inhibitor depends on various factors, including the patient's treatment history, viral load, and resistance profile. Some key points to consider when selecting a ritonavir-boosted protease inhibitor include:
- Darunavir/ritonavir is often preferred due to its high genetic barrier to resistance and favorable side effect profile, typically dosed as 800mg/100mg once daily for treatment-naive patients or 600mg/100mg twice daily for treatment-experienced patients 4.
- Atazanavir/ritonavir (300mg/100mg daily) is another common option but may cause hyperbilirubinemia and requires acid for absorption 4.
- Lopinavir is only available as a co-formulation with ritonavir (Kaletra) dosed as 400mg/100mg twice daily 5. These medications should be taken with food to enhance absorption, and patients should be monitored for potential side effects including gastrointestinal disturbances, lipid abnormalities, and drug interactions, as ritonavir is a potent inhibitor of multiple cytochrome P450 enzymes 6. It's also important to note that once-daily regimens are becoming increasingly popular due to increased convenience and have been shown to be at least as effective as twice-daily regimens in clinical studies 7. Overall, the selection of a ritonavir-boosted protease inhibitor should be individualized based on the patient's specific needs and medical history.