More common side effects:

• Abdominal or stomach pain
• bad, unusual, or unpleasant (after) taste in the mouth
• belching
• bloated or full feeling
• change in taste
• discoloration of the urine
• excess air or gas in the stomach or intestines
• headache
• nausea
• passing gas
• trouble sleeping

Check with your doctor immediately if any of the following side effects occur:

• Black, tarry stools
• chest pain
• chills
• cough
• diarrhea
• fever
• itching or skin rash
• loss of appetite
• painful or difficult urination
• sore throat
• ulcers, sores, or white spots in the mouth
• unusual bleeding or bruising
• unusual tiredness or weakness

Rifabutin is an antibiotic that treats infections caused by germs (bacteria) called mycobacteria. Mycobacteria cause infections such as tuberculosis and Mycobacterium avium complex (MAC) disease. 

Do not use rifabutin if:

• If you are allergic (hypersensitive) to this drug.
• If you are allergic to any drug containing rifamycin.

Make sure you tell your doctor if you have any other medical problems, especially:

• Diarrhea
• Inflammation of the muscle
• Uveitis 
• Severe kidney disease

Drug Interactions:

The following drugs may interact with rifabutin:

• medications to treat diabetes
• acetylsalicylic acid (ASA)
• methadone
• warfarin
• prednisone
• medications to suppress the immune system like cyclosporine and tacrolimus
• quinidine or digitalis (digoxin is okay)
• dapsone
• phenytoin (Dilantin)
• medications to treat fungal infections like fluconazole, itraconazole, posaconazole, voriconazole, ketoconazole and miconazole
• medications to treat viral infections like indinavir, saquinavir, ritonavir or amprenavir, fosamprenavir/ritonavir, lopinavir/ritonavir and tipranavir/ritonavir
• delviradine
• clarithromycin
• birth control pills that have ethinyl estradiol and/or norethindrone.

Use in pregnancy: There is no human data available on safety in pregnancy. Animal studies suggest low risk.

Use in breastfeeding: There is no human data available on safety in breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.