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Last reviewed on RxList: 5/26/2020
Rifater Side Effects Center

What Is Rifater?

Rifater (rifampin, isoniazid and pyrazinamide) is a combination of antibiotics used to treat tuberculosis (TB).

What Are Side Effects of Rifater?

Common side effects of Rifater include:

  • nausea,
  • vomiting,
  • upset stomach,
  • stomach pain,
  • heartburn,
  • diarrhea,
  • muscle or joint pain,
  • headache,
  • rash or itching,
  • drowsiness,
  • dizziness,
  • spinning sensation,
  • ringing in your ears, or
  • numbness or tingling in your legs.

Tell your doctor if you have unlikely but serious side effects of Rifater include:

  • painful or swollen joints,
  • changes in the amount of urine,
  • increased thirst or urination,
  • bloody urine,
  • vision changes,
  • fast heartbeat,
  • easy bruising or bleeding,
  • signs of a new infection (such as fever, persistent sore throat),
  • mental/mood changes (such as confusion, psychosis), or
  • seizures.

Dosage for Rifater

Rifater is recommended in the initial phase of short-course therapy, which is usually continued for 2 months. Dose is determined by the patient's body weight.

What Drugs, Substances, or Supplements Interact with Rifater?

Rifater may interact with cyclosporine, haloperidol, nortriptyline, probenecid, theophylline, antibiotics, antifungal medications, barbiturates, birth control pills or hormone replacement therapy, blood thinners, oral diabetes medications, heart or blood pressure medications, heart rhythm medications, narcotics, sedatives, seizure medications, steroids, or sulfa drugs. Many other medicines can interact with Rifater.

Rifater During Pregnancy and Breastfeeding

Tell your doctor all prescription and over-the-counter medications you use. During pregnancy, Rifater should be used only when prescribed. When rifampin is taken during the last few weeks of pregnancy, the risk of bleeding in both mother and infant may be increased. Tell your doctor if you notice any bleeding in your newborn. This medication passes into breast milk but the effect on a nursing infant is unknown. Consult your doctor before breastfeeding.

Additional Information

Our Rifater (rifampin, isoniazid and pyrazinamide) 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.


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Rifater Consumer Information

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Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning in your eyes, skin pain, red or purple skin rash that spreads and causes blistering and peeling).

Seek medical treatment if you have a serious drug reaction that can affect many parts of your body. Symptoms may include: skin rash, fever, swollen glands, muscle aches, severe weakness, unusual bruising, and joint pain or stiffness.

Rifater can cause severe liver symptoms, especially in people who are 35 and older. Call your doctor at once if you have any of these early signs of liver damage: nausea, vomiting, upper stomach pain, weakness, tiredness, loss of appetite, or yellowing of your skin or eyes.

Also call your doctor right away if you have:

  • numbness, tingling, or burning pain in your hands or feet;
  • vision problems, pain behind your eyes;
  • wheezing, trouble breathing; or
  • severe stomach pain, diarrhea that is watery or bloody.

Common side effects may include:

  • numbness or tingling;
  • red discoloration of your teeth, sweat, urine, saliva, and tears;
  • nausea, vomiting, stomach pain;
  • mild rash or itching; or
  • joint or muscle pain.

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.

Read the entire detailed patient monograph for Rifater (Rifampin, Isoniazid and Pyrazinamide)


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Rifater Professional Information


Adverse Experiences During The Clinical Trial

Adverse event data reported for the RIFATER and the separate drug treatment groups during the first 2 months of the trial are shown in the table below.

Adverse Events Reported During the Clinical Study

Adverse Events by Body Systems During First 2 Months of TrialNumber of Patients with Adverse Events*
Cutaneous (rash, erythroderma, erythema, exfoliative dermatitis, Lyell syndrome, urticaria, localized skin rash, diffuse skin rash, pruritus, generalized hypersensitivity)8 (7%)21 (17%)
Gastrointestinal (nausea, vomiting, digestive pain, diarrhea)8 (7%)14 (11%)
Musculoskeletal (arthralgia, long bones pain, phlebitis, localized joint pain, diffuse joint pain, edema of the legs)5 (4%)8 (7%)
Hearing and Vestibular (tinnitus, vertigo, vertigo with loss of equilibrium)3 (2%)6 (5%)
Liver and Biliary (hepatitis with conjunctival jaundice, hepatitis with deep jaundice)0 (0%)2 (2%)
Central and Peripheral Nervous System (sweating, headache, insomnia, diffuse paresthesia of the legs, anxiety, diabetic coma)5 (4%)4 (3%)
Total Body (spiking fever, persistent fever)2 (2%)4 (3%)
Cardiorespiratory (tightness in chest, coughing, diffuse chest pain, hemoptysis, angina, palpitation, total pneumothorax)8 (7%)3 (2%)
Total number of patients with one or more adverse events2943
* A given patient may have experienced ≥1 adverse event.
† Isoniazid, rifampin, and pyrazinamide dosed as separate tablets and capsules.
‡ A total of 250 patients (124 RIFATER; 126 separate) were originally enrolled in the study. Five patients (2 RIFATER; 3 separate) were excluded due to admission errors.

No serious adverse events were reported in the patients receiving RIFATER tablets. Three serious adverse events were reported in the patients given isoniazid, rifampin, and pyrazinamide as separate tablets and capsules. The three serious adverse events were two general hypersensitivity reactions and one jaundice reaction.

There were no significant differences between the two treatment groups in standard liver function, renal function, and hematological laboratory test values measured at baseline and after 8 weeks of treatment. As would be expected for these drugs, there were alterations in liver enzymes (SGOT, SGPT) and serum uric acid levels. The adverse reactions reported during therapy with RIFATER are consistent with those described below for the individual components.

Adverse Reactions Reported For Individual Components Of RIFATER



Heartburn, epigastric distress, anorexia, nausea, vomiting, jaundice, flatulence, cramps, and diarrhea have been noted in some patients. Although Clostridium difficile has been shown in vitro to be sensitive to rifampin, pseudomembranous colitis has been reported with the use of rifampin (and other broad spectrum antibiotics). Therefore, it is important to consider this diagnosis in patients who develop diarrhea in association with antibiotic use. Tooth discoloration (which may be permanent) may occur.


Hepatotoxicity including transient abnormalities in liver function tests (e.g., elevations in serum bilirubin, alkaline phosphatase, serum transaminases, gamma-glutamyl transferase), hepatitis, a shock-like syndrome with hepatic involvement and abnormal liver function tests, and cholestasis have been reported (see WARNINGS).


Thrombocytopenia has occurred primarily with high dose intermittent therapy but has also been noted after resumption of interrupted treatment. It rarely occurs during well-supervised daily therapy. This effect is reversible if the drug is discontinued as soon as purpura occurs. Cerebral hemorrhage and fatalities have been reported when rifampin administration has been continued or resumed after the appearance of purpura.

Rare reports of disseminated intravascular coagulation have been observed.

Leukopenia, hemolytic anemia, decreased hemoglobin, bleeding, and vitamin K-dependent coagulation disorders (abnormal prolongation of prothrombin time or low vitamin K-dependent coagulation factors) have been observed.

Agranulocytosis has been reported rarely.

Central Nervous System

Headache, fever, drowsiness, fatigue, ataxia, dizziness, inability to concentrate, mental confusion, behavioral changes, muscular weakness, pains in extremities, and generalized numbness have been observed.

Psychoses have been rarely reported.

Rare reports of myopathy have also been observed.


Visual disturbances have been observed.


Menstrual disturbances have been observed.

Rare reports of adrenal insufficiency in patients with compromised adrenal function have been observed.


Elevations in BUN and serum uric acid have been reported. Rarely, hemolysis, hemoglobinuria, hematuria, interstitial nephritis, acute tubular necrosis, 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.


Cutaneous reactions are mild and self-limiting and do not appear to be hypersensitivity reactions. Typically, they consist of flushing and itching with or without a rash. More serious cutaneous reactions which may be due to hypersensitivity occur but are uncommon.

Hypersensitivity Reactions

Occasionally pruritus, urticaria, rash, pemphigoid reaction, erythema multiforme, acute generalized exanthematous pustulosis, Stevens-Johnson syndrome, toxic epidermal necrolysis, Drug Reaction with Eosinophilia and Systemic Symptoms syndrome (see WARNINGS), vasculitis, eosinophilia, sore mouth, sore tongue, and conjunctivitis have been observed.

Anaphylaxis has been reported rarely.


Edema of the face and extremities has been reported. Other reactions which have occurred with intermittent dosage regimens include “flu” syndrome (such as episodes of fever, chills, headache, dizziness, and bone pain), shortness of breath, wheezing, decrease in blood pressure and shock. The “flu” syndrome may also appear if rifampin is taken irregularly by the patient or if daily administration is resumed after a drug-free interval.


The most frequent reactions are those affecting the nervous system and the liver. (See the BOXED WARNING.)

Nervous System

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 paresthesia 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.


Pancreatitis, nausea, vomiting, and epigastric distress.


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% 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% of those over 50 years of age.


Agranulocytosis; hemolytic, sideroblastic, or aplastic anemia; thrombocytopenia; and eosinophilia.

Hypersensitivity Reactions

Fever, skin eruptions (morbilliform, maculopapular, purpuric, or exfoliative), lymphadenopathy, anaphylactic reactions, Stevens-Johnson syndrome, toxic epidermal necrolysis (see WARNINGS, Isoniazid), Drug Reaction with Eosinophilia and Systemic Symptoms syndrome (see WARNINGS), and vasculitis.

Metabolic And Endocrine

Pyridoxine deficiency, pellagra, hyperglycemia, metabolic acidosis, and gynecomastia.


Rheumatic syndrome and systemic lupus erythematosus-like syndrome.


The principal adverse effect is a hepatic reaction (see WARNINGS). Hepatotoxicity appears to be dose related and may appear at any time during therapy. Pyrazinamide can cause hyperuricemia and gout (see PRECAUTIONS).


GI disturbances including nausea, vomiting, and anorexia have also been reported.

Hematologic And Lymphatic

Thrombocytopenia and sideroblastic anemia with erythroid hyperplasia, vacuolation of erythrocytes and increased serum concentration have occurred rarely with this drug. Adverse effects on blood clotting mechanisms have also been rarely reported.


Mild arthralgia and myalgia have been reported frequently. Hypersensitivity reactions including Drug Reaction with Eosinophilia and Systemic Symptoms syndrome (see WARNINGS), rashes, urticaria, pruritus, and erythema have been reported. Angioedema has been reported rarely. Fever, acne, photosensitivity, porphyria, dysuria, and interstitial nephritis have been reported rarely.

Read the entire FDA prescribing information for Rifater (Rifampin, Isoniazid and Pyrazinamide)

Related Resources for Rifater

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© Rifater Patient Information is supplied by Cerner Multum, Inc. and Rifater Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.


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