Fusion inhibitor approved for use in HIV is: (D. REPEAT Feb 2014)
**Core Concept**
The question tests the knowledge of a specific class of antiretroviral drugs used in the management of HIV/AIDS. Fusion inhibitors are a type of antiretroviral drug that work by blocking the fusion of the HIV virus with the host cell membrane, thereby preventing viral entry and replication.
**Why the Correct Answer is Right**
The correct answer is a fusion inhibitor that binds to the gp41 subunit of the HIV envelope glycoprotein, preventing the conformational change required for viral fusion with the host cell membrane. This class of drugs is particularly useful in the treatment of HIV as it targets a critical step in the viral life cycle. The use of fusion inhibitors has been shown to significantly reduce viral loads and improve clinical outcomes in patients with HIV.
**Why Each Wrong Option is Incorrect**
* **Option A:** This is incorrect because it is not a fusion inhibitor. It may be a different class of antiretroviral drug, such as a protease inhibitor or an nucleoside reverse transcriptase inhibitor (NRTI).
* **Option B:** This is incorrect because it is not a fusion inhibitor. It may be a different class of antiretroviral drug, such as a non-nucleoside reverse transcriptase inhibitor (NNRTI) or an entry inhibitor.
* **Option C:** This is incorrect because it is not a fusion inhibitor. It may be a different class of antiretroviral drug, such as a fusion inhibitor (but the specific drug is not correct) or an integrase strand transfer inhibitor (INSTI).
**Clinical Pearl / High-Yield Fact**
A common side effect of fusion inhibitors is rash, which may be a dose-dependent phenomenon. This is an important consideration when initiating therapy with a fusion inhibitor.
**Correct Answer: D. Maraviroc**