With any medication side effects can present themselves. While starting out with PrEP, some have experienced: nausea, tiredness, gastrointestinal issues and headaches. In some instances, people have had issues with their kidneys or bones, though these issues would not be permanent if you had to stop taking PrEP. These issues will be monitored while you remain on PrEP as you will have to go in for blood work every three months to renew your prescription. If any side effects or symptoms last too long, consult your doctor or medical professional.