Always check with your doctor before starting a new medication. PrEP can interact with some painkillers that are non-steroidal anti-inflammatory drugs (NSAIDs). These include diclofenac, ibuprofen, and naproxen. Taking PrEP with these NSAIDs can sometimes cause kidney problems. Avoid using these medications if you are taking PrEP, or let your doctor know if you need to use them.