Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Tybost (Cobicistat).

Fat redistribution: Over time, Tybost (Cobicistat) may change how fat is distributed in your body and may change your body shape. You may notice increased fat in the upper back and neck, breast, around the back, chest, and stomach area; or loss of fat from the legs, arms, and face. The long-term effects of this are not known.

Hepatitis B and Hepatitis C Infection: The safety and effectiveness of using Tybost (Cobicistat) with co-existing liver disorders have not well been studied. People with chronic hepatitis B or C who are also using antiretroviral medications are at an increased risk of developing severe and possibly fatal liver problems. Your doctor may test for hepatitis B and hepatitis C before prescribing Tybost (Cobicistat). If you have a history of other liver disease, discuss with your doctor how Tybost (Cobicistat) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Tybost (Cobicistat), and whether any special monitoring is needed.

Immune reconstitution syndrome: Tybost (Cobicistat) may cause immune reconstitution syndrome, where signs and symptoms of inflammation from previous infections appear. These symptoms occur soon after starting anti-HIV medication and can vary. They are thought to occur as a result of the immune system improving and being able to fight infections that have been present without symptoms (such as pneumonia, herpes, hepatitis, or Tuberculosis). Report any new symptoms to your doctor immediately.

Kidney function: Tybost (Cobicistat) may cause a slight decrease in kidney function. While this is not normally a problem, if it is combined with another anti-HIV medication, tenofovir, it may cause kidney failure. If you have decreased kidney function or Kidney Disease, discuss with your doctor how Tybost (Cobicistat) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Tybost (Cobicistat), and whether any special monitoring is needed. Tybost (Cobicistat) is not recommended for people with severely reduced kidney function.

Liver function: The safety and effectiveness of using Tybost (Cobicistat) with liver disorders have not well been studied. People with chronic hepatitis B or C who are also using antiretroviral medications are at an increased risk of developing severe and possibly fatal liver problems. If you have decreased liver function or liver disease, discuss with your doctor how Tybost (Cobicistat) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Tybost (Cobicistat), and whether any special monitoring is needed. Tybost (Cobicistat) is not recommended for people with severely reduced liver function.

Pregnancy: Tybost (Cobicistat) should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Tybost (Cobicistat), contact your doctor immediately.

Breast-feeding: It is not known if Tybost (Cobicistat) passes into breast milk. Women who have HIV infection are cautioned against breast-feeding because of the risk of passing HIV to a baby who does not have the infection.

Children: The safety and effectiveness of using Tybost (Cobicistat) have not been established for children.