Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Antibiotic-related diarrhea: As with other antibacterial medications, rifampin can cause a severe form of diarrhea associated with a condition known as pseudomembranous colitis. If you develop severe diarrhea while taking (or within a few weeks of taking) this medication, contact your doctor.
Birth control: Rifampin can reduce the effectiveness of hormonal birth control, which may lead to unplanned pregnancy. Women who may become pregnant while taking rifampin should use another or a second method of birth control.
Red-orange discolouration: Rifampin causes substances produced by the body, such as stools, urine, tears, and sweat, to be coloured red-orange. This discoloration can cause contact lenses to become permanently stained.
Liver function: Rifampin can cause liver failure, which has in some cases caused death. This may be more likely to occur if you already have decreased liver function. Liver disease or reduced liver function may also cause this medication to build up in the body, causing side effects. If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking this medication.
If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.
Porphyria: Rifampin may cause attacks of a condition called acute porphyria (a disorder that affects the production of heme in the body). If you have porphyria, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Pregnancy: This medication crosses the placental barrier, but its effect on a developing baby is not clear. Rifampin should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding: This medication passes into breast milk. If you are a breast-feeding mother and are taking rifampin, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.
Children: Rifampin should not be given to premature infants or newborns, as the liver may not be fully active.