SIDE EFFECTS: This drug may cause upset stomach, heartburn, nausea, menstrual changes, headache, drowsiness, or dizziness. If any of these effects persist or worsen, inform your doctor promptly. This medication may cause urine, sweat, saliva, or tears to change color (yellow, orange, red, or brown). This effect is harmless and will go away when the medication is stopped. However, teeth and contact lens staining may be permanent. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Rifampin may rarely cause serious liver disease. Though sometimes necessary to completely treat certain infections, combination treatment with other drugs (e.g., isoniazid, pyrazinamide) may increase this risk. Tell your doctor right away if any of these unlikely but serious side effects occur: signs of kidney problems (such as change in the amount of urine), persistent nausea/vomiting, stomach/abdominal pain, dark urine, yellowing eyes/skin, mental/mood changes (e.g., confusion, unusual behavior), unusual tiredness, easy bruising/bleeding, small red spots on the skin, joint pain/swelling. This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a type of resistant bacteria. This condition may occur during treatment or weeks to months after treatment has stopped. Do not use anti-diarrhea or opioid medications if you have any of the following symptoms because these products may make them worse. Tell your doctor right away if you develop: persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool. Use of this medication for prolonged or repeated periods may result in oral thrush or a new yeast infection (oral/vaginal fungal infection). Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: fever that doesn't go away, new or worsening lymph node swelling, rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking rifampin, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. Before using this medication, tell your doctor or pharmacist your medical history, especially of: diabetes, liver problems (e.g., hepatitis), HIV infection, history of alcohol use/abuse. This drug may make you dizzy or drowsy. Alcohol or marijuana can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana. Rifampin may cause live bacterial vaccines (such as typhoid vaccine) to not work as well. Do not have any immunizations/vaccinations while using this medication unless your doctor tells you to. Before having surgery, tell your doctor or dentist that you are using this drug. During pregnancy, this medication should be used only when clearly needed. When this drug is taken during the last few weeks of pregnancy, the risk of bleeding in both mother and infant may be increased. Tell your doctor right away if you notice any bleeding in your newborn. Discuss the risks and benefits with your doctor. Rifampin passes into breast milk but is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. Rifampin can speed up the removal of other medications from your body, which may affect how they work. Examples of affected drugs include aprepitant, digoxin, ranolazine, sulfasalazine, tacrolimus, theophylline, certain anti-infectives (including chloramphenicol, clarithromycin, dapsone, doxycycline, linezolid, telithromycin, zidovudine, quinolones such as ciprofloxacin), antiarrhythmics (such as disopyramide, mexiletine, quinidine), certain antimalarial drugs (such as atovaquone, quinine), anti-seizure drugs (such as phenytoin, phenobarbital, lamotrigine), azole antifungals (such as itraconazole, ketoconazole, voriconazole), benzodiazepines (such as midazolam), "blood thinners" (such as warfarin), calcium channel blockers (such as diltiazem, nimodipine, verapamil), certain anti-cancer drugs (such as imatinib, irinotecan), certain oral drugs for diabetes (such as repaglinide), certain hormone replacement drugs (including estrogens such as conjugated estrogen, progestins such as medroxyprogesterone), certain drugs for mental/mood disorders (including clozapine, haloperidol, tricyclic antidepressants such as amitriptyline), narcotic pain relievers (such as methadone), HIV NNRTIs (such as delavirdine, etravirine, nevirapine), HIV protease inhibitors (such as atazanavir, ritonavir, saquinavir), certain drugs for sleep (such as ramelteon, eszopiclone, zopiclone), among others. This medication may decrease the effectiveness of hormonal birth control such as pills, patch, or ring. This could cause pregnancy. Discuss with your doctor or pharmacist if you should use additional reliable birth control methods while using this medication. Also tell your doctor if you have any new spotting or breakthrough bleeding, because these may be signs that your birth control is not working well. This medication may interfere with certain laboratory tests (urine screening for opiates, blood serum folate/vitamin B12), possibly causing false test results. Rifampin may also make it harder for your body to get rid of certain chemicals used in gallbladder tests. Make sure laboratory personnel and all your doctors know you use this drug.

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include swelling face/eyes, whole-body itching, orange/red discoloration of skin/eyes, nausea/vomiting, stomach/abdominal pain, increasing tiredness, fainting.