Some common side effects include appetite loss, dizziness, flu-like symptoms, headache, nausea, vomiting, diarrhea, stomach pain, and vision changes. Rifampin can also cause discoloration of body fluids and teeth, and staining of contact lenses (avoid wearing contact lenses while taking rifampin). Serious reactions can also occur. Before taking rifampin, discuss potential side effects with your healthcare provider. Avoid alcohol while on this medication, as alcohol can increase the risk of liver problems.