Answer
Lopinavir blocks HIV protease. Ritonavir slows lopinavir metabolism, allowing higher and more sustained lopinavir exposure.
Sources for this answer
- Kaletra 100mg/25mg film-coated tablets (Great Britain) — Current selected SmPCemc · Summary of Product Characteristics
- Kaletra 80mg/20mg Oral Solution (Great Britain) — Current selected SmPCemc · Summary of Product Characteristics
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