This medication is used to prevent and treat tuberculosis and other bacterial infections. Rifampin belongs to a class of drugs known as rifamycin antibiotics. It works by stopping the growth of bacteria.

This antibiotic treats only bacterial infections. It will not work for viral infections (such as common cold, flu). Using any antibiotic when it is not needed can cause it to not work for future infections.

Take this medication by mouth at least 1 hour before or 2 hours after a meal as directed by your doctor, usually 1 or 2 times daily. Take this medication with a full glass of water (8 ounces/240 milliliters) unless your doctor directs you otherwise. If you need to take antacids, wait at least 1 hour after taking rifampin.

If you are unable to swallow the capsules, you may open the capsule and sprinkle the contents onto applesauce or jelly. Eat the entire mixture right away. Do not prepare a supply for future use.

If you are using the liquid form of this medication, shake the bottle well before each use. Carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose.

The dosage and length of treatment are based on your medical condition, weight, and response to treatment.

It is very important to keep using this medication (and other medications used to treat tuberculosis) exactly as prescribed by your doctor. Do not skip any doses.

For the best effect, use this antibiotic at evenly spaced times. To help you remember, use this medication at the same time(s) every day.

Continue to use this medication until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the infection.

Tell your doctor if your condition lasts or gets worse.

Upset stomach, heartburn, nausea, or headache may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

This medication may cause urine, sweat, saliva, or tears to change color (yellow, orange, red, or brown). This effect is harmless and will disappear when the medication is stopped. However, teeth and contact lens staining may be permanent.

Remember that this medication has been prescribed because your doctor 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.

Tell your doctor right away if you have any serious side effects, including:

• signs of kidney problems (such as change in the amount of urine)
• mental/mood changes (such as confusion, unusual behavior)
• unusual tiredness
• easy bruising/bleeding
• small red spots on the skin
• joint pain/swelling
• new or worsening shortness of breath

Get medical help right away if you have any very serious side effects, including:

• chest pain

Rifampin may rarely cause serious (possibly fatal) liver disease. Get medical help right away if you have any symptoms of liver damage, such as:

• nausea/vomiting that doesn't stop
• loss of appetite
• stomach/abdominal pain
• yellowing eyes/skin
• dark urine

This medication may rarely cause a severe intestinal condition due to a bacteria called C. difficile. This condition may occur during treatment or weeks to months after treatment has stopped. Tell your doctor right away if you develop:

• diarrhea that doesn't stop
• abdominal or stomach pain/cramping
• blood/mucus in your stool

If you have these symptoms, do not use anti-diarrhea or opioid products because they may make symptoms worse.

This medication may sometimes cause oral thrush or a new yeast 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.

Before using rifampin, tell your doctor or pharmacist if you are allergic to it; or other rifamycins (such as rifabutin); 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 (such as hepatitis)
• HIV infection
• history of alcohol use/abuse

Alcohol may increase the risk of liver disease. Avoid alcoholic beverages while using this medication.

Rifampin may cause live bacterial vaccines (such as typhoid vaccine) to not work well. Tell your health care professional that you are using rifampin before having any immunizations/vaccinations.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

During pregnancy, this medication should be used only when clearly needed. When this drug is used 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 breastfeeding.

See also How to Use section.

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 interacts with many medications. While you are using rifampin, it is very important to tell your doctor or pharmacist of any changes in medications that you are taking.

Rifampin can speed up the removal of other medications from your body, which may affect how they work. Examples of affected drugs include atovaquone, certain anti-cancer drugs (such as irinotecan), certain azole antifungals (such as itraconazole), certain calcium channel blockers (such as nifedipine), certain products used to treat chronic hepatitis C (such as sofosbuvir), cobicistat, lurasidone, HIV NNRTIs (such as etravirine, nevirapine), praziquantel, HIV protease inhibitors (such as atazanavir, darunavir), 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 reliable backup 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 lab tests (such as 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 lab personnel and all your doctors know you use this drug.

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 1-800-222-1222. Canada residents can call 1-844-764-7669.

Do not share this medication with others.

Lab and/or medical tests (such as liver/kidney function, bilirubin, complete blood count) may be done before you start using this medication and while you are using it. Keep all medical and lab appointments. Consult your doctor for more details.

This medication has been prescribed for your current condition only. Do not use it later for another infection unless your doctor tells you to.

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

If you are taking this drug on a longer schedule (such as twice weekly) and miss a dose, ask your doctor or pharmacist right away for a new dosing schedule.

Store the capsules at room temperature away from light and moisture. Do not store in the bathroom. Store the liquid form in the refrigerator or at room temperature. Do not freeze. The liquid form expires 4 weeks after it was prepared by the pharmacy. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.