### Types of NRTIs and Their Side Effects If you're being treated for an HIV infection, your doctor might prescribe a type of drug called an NRTI (nucleoside/nucleotide reverse transcriptase inhibitor), often referred to as 'nukes.' These drugs are usually part of a combination therapy known as antiretroviral therapy (ART), which often includes drugs from other classes like integrase inhibitors. Sometimes, this combination is available in a single pill. NRTIs work by blocking an enzyme called reverse transcriptase, which HIV uses to replicate itself. This helps prevent the virus from spreading in your body. Some FDA-approved NRTIs include tenofovir, emtricitabine, lamivudine, and abacavir. #### Common Side Effects - Nausea - Fatigue - Headache - Diarrhea #### Serious Side Effects While newer NRTIs like tenofovir, emtricitabine, lamivudine, and abacavir are less likely to cause serious side effects, they can still occur. Rarely, NRTIs may cause: - Lactic acidosis (a buildup of lactic acid in the blood) - Liver problems - Pancreatitis #### Specific NRTIs and Their Risks - **Lamivudine and Emtricitabine**: High chance of drug resistance, often combined with other drugs. - **Abacavir**: May cause a serious allergic reaction, especially in people with a genetic variation called HLA-B*5701. It may also increase the risk of a heart attack. - **Tenofovir Disoproxil Fumarate**: May cause kidney problems and bone loss. If these issues arise, your doctor might switch you to Tenofovir Alafenamide, which is safer for bones and kidneys but may cause weight gain. - **Zidovudine**: May cause anemia and muscle weakness, and rarely, it can lower your white blood cell count. Always consult your doctor for the best treatment plan and report any side effects you experience. Regular blood tests will help monitor your health during treatment.