INSTIs, or Integrase Strand Transfer Inhibitors, are a class of antiretroviral drugs used to treat HIV. They work by blocking the integrase enzyme, which is essential for the virus to insert its genetic material into the host's DNA. This action helps prevent the virus from replicating and spreading in the body. Common INSTIs include Raltegravir, Elvitegravir, and Dolutegravir. These medications are often preferred due to their effectiveness, low side effects, and convenience, as they can be taken once daily. INSTIs are a key component of modern HIV treatment regimens.