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Rifamate Side Effects Center
Medical Editor: John P. Cunha, DO, FACOEP
Rifamate (rifampin and isoniazid) is a combination of two antibiotics used to treat tuberculosis. Common side effects of Rifamate include allergic reactions, excessive tiredness or weakness, nausea, vomiting, diarrhea, loss of appetite, yellow skin or eyes, unusual bruising or bleeding, dark urine, little or no urine, numbness or tingling in your hands or feet, muscle or bone pain, seizures, blurred vision, fever, chills, sore throat, headache, rash, itching, confusion, or abnormal behavior.
The recommended dosage of Rifamate is two capsules taken one hour before or two hours after a meal once a day. Liver function tests should be performed prior to taking Rifamate as it may cause liver dysfunction, especially if you have liver disease. Tell your doctor if you take drugs such as acetaminophen or consume alcohol on a regular basis as these may increase your risk of liver damage. Caution should be taken if you are pregnant or breastfeeding while taking Rifamate.
Our Rifamate (rifampin and isoniazid) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What is Patient Information in Detail?
Easy-to-read and understand detailed drug information and pill images for the patient or caregiver from Cerner Multum.
Rifamate in Detail - Patient Information: Side Effects
If you experience any of the following serious side effects, stop taking isoniazid and rifampin and seek emergency medical attention or contact your doctor immediately:
- an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives);
- excessive tiredness or weakness;
- nausea, vomiting, diarrhea, or loss of appetite;
- yellow skin or eyes;
- unusual bruising or bleeding;
- dark urine;
- little or no urine;
- numbness or tingling in your hands or feet;
- muscle or bone pain;
- blurred vision;
- fever, chills, or a sore throat;
- a headache;
- a rash or itching; or
- confusion or abnormal behavior.
Other, less serious side effects may be more likely to occur. Continue to take isoniazid and rifampin and talk to your doctor if you experience
- red-orange coloration of tears, sweat, saliva, urine, or feces; or
- mild tiredness or weakness.
Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome. You may report side effects to FDA at 1-800-FDA-1088.
Read the entire detailed patient monograph for Rifamate (Rifampin and Isoniazid) »
What is Patient Information Overview?
A concise overview of the drug for the patient or caregiver from First DataBank.
Rifamate Overview - Patient Information: Side Effects
Nausea/vomiting, upset stomach, heartburn, or headache may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
This medication may cause urine, sweat, saliva, or tears to turn reddish. This effect is harmless and will disappear when the medication is stopped. However, dentures and contact lenses may become permanently stained.
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.
Tell your doctor immediately if any of these unlikely but serious side effects occur: numbness/tingling of arms/legs, painful/swollen joints.
Tell your doctor immediately if any of these rare but serious side effects occur: change in the amount of urine, increased thirst/urination, bloody urine, vision changes, easy bruising/bleeding, signs of a new infection (such as fever, persistent sore throat), mental/mood changes (such as confusion, psychosis), seizures.
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 products or narcotic pain medications if you have any of the following symptoms because these products may make them worse. Tell your doctor immediately if you develop: persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool.
A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: 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.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Read the entire patient information overview for Rifamate (Rifampin and Isoniazid)»
What is Prescribing information?
The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.
Rifamate FDA Prescribing Information: Side Effects
Nervous system reactions: headache, drowsiness, fatigue, ataxia, dizziness, inability to concentrate, mental confusion, visual disturbances, muscular weakness, pain in extremities, and generalized numbness
Hepatic reactions: transient abnormalities in liver function tests (e.g., elevations in serum bilirubin, BSP, alkaline phosphatase, serum transaminases) have been observed. Rarely, hepatitis or a shocklike syndrome with hepatic involvement and abnormal liver function tests.
Renal reactions: elevations in BUN and serum uric acid have been reported. Rarely, hemolysis, hemoglobinuria, hematuria, interstitial nephritis, renal insufficiency, and acute renal failure have been noted. These are generally considered to be hypersensitivity reactions. They usually occur during intermittent therapy or when treatment is resumed following intentional or accidental interruption of a daily dosage regimen, and are reversible when rifampin is discontinued and appropriate therapy instituted.
Hematologic reactions: thrombocytopenia, leukopenia, hemolytic anemia, eosinophilia, and decreased hemoglobin have been observed. Thrombocytopenia has occurred when rifampin and ethambutol were administered concomitantly according to an intermittent dose schedule twice weekly and in high doses. Agranulocytosis has been reported very rarely.
Allergic and immunological reactions:occasionally pruritus, urticaria, rash, pemphigoid reaction, eosinophilia, sore mouth, sore tongue, and exudative conjunctivitis. Rarely, hemolysis, hemoglobinuria, hematuria, renal insufficiency or acute renal failure have been reported which are generally considered to be hypersensitivity reactions. These have usually occurred during intermittent therapy or when treatment was resumed following intentional or accidental interruption of a daily dosage regimen and were reversible when rifampin was discontinued and appropriate therapy instituted.
Although rifampin has been reported to have an immunosuppressive effect in some animal experiments, available human data indicate that this has no clinical significance.
Metabolic reactions: elevations in BUN and serum uric acid have occurred.
Miscellaneous reactions: fever and menstrual disturbances have been noted.
The most frequent reactions are those affecting the nervous system and the liver.
Nervous system reactions:peripheral neuropathy is the most common toxic effect. It is dose-related, occurs most often in the malnourished and in those predisposed to neuritis (e.g., alcoholics and diabetics), and is usually preceded by paresthesias of the feet and hands. The incidence is higher in “slow inactivators.”
Other neurotoxic effects, which are uncommon with conventional doses, are convulsions, toxic encephalopathy, optic neuritis and atrophy, memory impairment, and toxic psychosis.
Gastrointestinal reactions: nausea, vomiting, and epigastric distress
Hepatic reactions:elevated serum transaminases (SGOT; SGPT), bilirubinemia, bilirubinuria, jaundice, and occasionally severe and sometimes fatal hepatitis. The common prodromal symptoms are anorexia, nausea, vomiting, fatigue, malaise, and weakness. Mild and transient elevation of serum transaminase levels occurs in 10 to 20 percent of persons taking isoniazid. The abnormality usually occurs in the first 4 to 6 months of treatment but can occur at any time during therapy. In most instances, enzyme levels return to normal with no necessity to discontinue medication. In occasional instances, progressive liver damage occurs, with accompanying symptoms. In these cases, the drug should be discontinued immediately. The frequency of progressive liver damage increases with age. It is rare in persons under 20, but occurs in up to 2.3 percent of those over 50 years of age.
Hematologic reactions:agranulocytosis, hemolytic sideroblastic or aplastic anemia, thrombocytopenia, and eosinophilia
Miscellaneous reactions: rheumatic syndrome and systemic lupus erythematosus-like syndrome
Read the entire FDA prescribing information for Rifamate (Rifampin and Isoniazid) »
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Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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