**Core Concept**
Protease inhibitors are a class of medications used to treat various viral infections, including HIV and hepatitis C. They work by inhibiting the activity of proteases, enzymes that are essential for the replication and maturation of viral particles.

**Why the Correct Answer is Right**
Protease inhibitors bind to the active site of the protease enzyme, preventing it from cleaving the viral polyprotein into functional proteins. This interruption in viral replication leads to a decrease in viral load and an increase in CD4+ T-cell count in HIV-infected individuals. Examples of protease inhibitors include ritonavir, saquinavir, and atazanavir.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because protease inhibitors do not directly target the viral RNA or DNA genome.
**Option B:** Incorrect because protease inhibitors can increase the levels of other antiretroviral medications by inhibiting their metabolism, a phenomenon known as pharmacokinetic boosting.
**Option C:** Incorrect because protease inhibitors can cause gastrointestinal side effects, such as diarrhea and nausea, but this is not the only mechanism of action or side effect.

**Clinical Pearl / High-Yield Fact**
Protease inhibitors can interact with other medications, including antiretroviral therapy (ART) and certain antacids, which can affect their efficacy and toxicity.

**Correct Answer: A. Protease inhibitors do not directly target the viral RNA or DNA genome.**