### How Booster Drugs Enhance HIV Treatments Doctors have many options for treating HIV, and one important component is the use of booster drugs. These drugs, also known as enhancers, are not designed to fight HIV directly but to make other HIV medications more effective. Two common booster drugs are cobicistat (Tybost) and ritonavir (Norvir). #### How They Work Booster drugs work by blocking enzymes called CYP3A, which break down HIV medications in the body. By inhibiting these enzymes, booster drugs increase the levels of HIV medications in the blood, making them more effective. This is particularly useful for drugs in the protease inhibitor and integrase inhibitor classes. #### Common Combinations Ritonavir is often combined with protease inhibitors like darunavir (Durart) or lopinavir (Kaletra). Cobicistat is usually combined with drugs like darunavir (Prezcobix, Symtuza) or atazanavir (Evotaz), and sometimes with the integrase inhibitor elvitegravir (Stribild, Genvoya). #### Taking Your Medication Always take your booster drugs as prescribed by your doctor, usually with food. Do not break or chew the pills. If you miss a dose, take it as soon as you remember unless it's almost time for your next dose. Never double up on doses. #### Side Effects At lower doses, ritonavir rarely causes side effects, but at higher doses, it can cause nausea, diarrhea, headache, and changes in taste. Cobicistat generally doesn't cause side effects on its own but may cause stomach issues when combined with other drugs. It can also cause jaundice or a rash when taken with atazanavir and may worsen kidney problems. #### Drug Interactions Because booster drugs affect how other medications are broken down in the body, they can interact with many other drugs. Always inform your doctor about any other medications or supplements you are taking. #### When to Contact Your Doctor If you experience any new or troubling symptoms, contact your doctor immediately. Serious side effects may require urgent medical attention. By understanding how booster drugs work and following your doctor's instructions, you can make your HIV treatment more effective.