Pre-exposure prophylaxis (PrEP) is a medication used to help prevent the transmission of human immunodeficiency virus (HIV). PrEP involves taking a daily dose of a combination of two antiretroviral (ARV) medications, tenofovir disoproxil fumarate and emtricitabine (TDF/FTC). Common side effects of PrEP include: Nausea: Some people may experience nausea, especially when first starting PrEP. This side effect usually goes away after a few days. Headache: Headaches are a common side effect of PrEP, but usually go away after a few days. Stomach problems: Some people may experience stomach problems, such as diarrhea, while taking PrEP. Fatigue: Fatigue is a common side effect of PrEP, and can be especially noticeable in the first few weeks of treatment. Skin rash: Some people may experience a skin rash while taking PrEP, which can be mild or severe. Depression and anxiety: PrEP can affect mood, and some people may experience depression or anxiety while taking PrEP. Insomnia: Some people may experience insomnia, or difficulty sleeping, while taking PrEP. Kidney problems: PrEP can cause a small decline in kidney function, which is usually not serious. However, it is important for people with pre-existing kidney problems to talk to their healthcare provider before starting PrEP. Liver problems: Some people may experience liver problems while taking PrEP, including an increase in liver enzymes. It's important to note that not everyone will experience these side effects, and some people may not experience any side effects at all. If you experience any side effects while taking PrEP, it's important to talk to your healthcare provider as soon as possible. They can recommend ways to manage side effects, or switch you to a different medication if necessary.