Isentress 400mg Tablet is an antiretrovirals. It is used to treat HIV (human immunodeficiency virus), the virus that can cause AIDS (acquired immunodeficiency syndrome). It prevents the multiplication of viruses in human cells and clears up your infection. Isentress 400mg Tablet is not a cure for HIV or AIDS and only helps to decrease the amount of HIV in your body. This helps to lower your risk of getting HIV-related complications and improves your lifespan. It is prescribed in combination with other HIV medicines. Your doctor will recommend the best medicines for you and will decide the doses that you need. Follow the instructions carefully, for all the medicines that you are given. It may be taken with or without food, preferably at a fixed time. Avoid taking antacids containing aluminum or magnesium within 2 hours before or 2 hours after you take this medicine. It is important not to miss doses and to keep taking them until your doctor tells you it is safe to stop. Some of the common side effects include insomnia (difficulty sleeping), headache, nausea, dizziness, and muscle pain. These are usually not serious but tell your doctor if they bother you or persist for a longer duration. Rarely, some people may experience a skin reaction or liver damage. Your doctor will closely monitor you for these in the initial period of treatment. Before taking it, tell your doctor if you have any skin problems or liver or kidney disease. While using it, you may need regular blood tests to check your blood counts and liver function. Avoid drinking alcohol as it may increase your risk of liver damage. Pregnant or breastfeeding mothers should consult their doctor before using this medicine. Do not have unprotected sex or share personal items like razors or toothbrushes, if you are HIV positive. Talk to your doctor about safe ways like condoms to prevent HIV transmission during sex.