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Rifater Side Effects

Generic Name: isoniazid / pyrazinamide / rifampin

Note: This document contains side effect information about isoniazid / pyrazinamide / rifampin. Some of the dosage forms listed on this page may not apply to the brand name Rifater.

For the Consumer

Applies to isoniazid / pyrazinamide / rifampin: oral tablet

Along with its needed effects, isoniazid / pyrazinamide / rifampin may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking isoniazid / pyrazinamide / rifampin:

More common
  • Clumsiness or unsteadiness
  • coughing or spitting up blood
  • dark urine
  • fast, irregular, pounding, or racing heartbeat or pulse
  • loss of appetite
  • nausea and vomiting
  • numbness, tingling, burning, or pain in the hands and feet
  • pain in large and small joints
  • tightness in the chest
  • unusual tiredness or weakness
  • yellow eyes or skin
Less common
  • Chills
  • difficulty in breathing
  • dizziness
  • fever
  • headache
  • hearing loss
  • muscle and bone pain
  • ringing or buzzing or other unexplained noise in ears
  • shivering
  • skin rash, itching, or redness
  • Black, tarry stools
  • bleeding gums
  • blistering, peeling, loosening of skin
  • bloody or cloudy urine
  • blurred vision or loss of vision, with or without eye pain
  • greatly decreased frequency of urination or amount of urine
  • mental depression
  • mood or mental changes
  • pinpoint red spots on skin
  • seizures
  • sore throat
  • unusual bleeding or bruising

Some side effects of isoniazid / pyrazinamide / rifampin may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Diarrhea
  • stomach pain
Less common
  • Sore mouth or tongue

For Healthcare Professionals

Applies to isoniazid / pyrazinamide / rifampin: oral tablet


Frequency not reported: Altered levels of liver enzymes (SGOP, SGPT)

Frequency not reported: Elevated serum transaminases (SCOT, SCPT), bilirubinemia, bilirubinuria, jaundice, hepatitis

Frequency not reported: Hepatotoxicity (e.g., hepatic cell function abnormality, liver tenderness, jaundice, acute yellow atrophy)

Rare (less than 0.1%): Hepatitis, shock-like syndrome with hepatic involvement
Frequency not reported: Abnormal liver function tests (e.g., elevations in serum bilirubin, alkaline phosphatase, serum transaminases), jaundice[Ref]


Frequency not reported: Altered levels of serum uric acid levels

Frequency not reported: Pyridoxine deficiency, pellagra, hyperglycemia, metabolic acidosis

Frequency not reported: Hyperuricemia, gout, anorexia, porphyria

Frequency not reported: Anorexia, elevated serum uric acid[Ref]


Common (1% to 10%): Rash, erythroderma, erythema, exfoliative dermatitis, Lyell syndrome, urticaria, localized skin rash, diffuse skin rash, pruritus, sweating

Frequency not reported: Stevens-Johnson syndrome, vasculitis, skin eruptions (morbilliform, maculopapular, purpuric, or exfoliative), rash, pemphigus, acne

Rare (less than 0.1%): Acne, photosensitivity
Frequency not reported: Rash, urticaria, pruritus, erythema

Uncommon (0.1% to 1%): Urticaria
Rare (less than 0.1%): Exfoliate dermatitis, pemphigoid reaction, erythema multiforme (Stevens-Johnson syndrome, Lyells syndrome, vasculitis)
Frequency not reported: Flushing, itching with or without a rash (mild, self-limiting), pruritus, rash, pemphigoid reaction, toxic epidermal necrolysis, vasculitis[Ref]


Common (1% to 10%): Generalized hypersensitivity

Frequency not reported: Anaphylactic reactions

Rare (less than 0.1%): Angioedema

Rare (less than 0.1%): Anaphylaxis[Ref]

Nervous system

Common (1% to 10%): Headache, insomnia, diffuse paresthesia of the legs, anxiety, diabetic coma, tinnitus, vertigo, vertigo with loss of equilibrium

Uncommon (0.1% to 1%): Convulsions, toxic encephalopathy, optic neuritis and atrophy, memory impairment
Frequency not reported: Peripheral neuropathy, vertigo, polyneuritis

Frequency not reported: Cerebral hemorrhage, headache, drowsiness, ataxia, dizziness, inability to concentrate, generalized numbness[Ref]


Common (1% to 10%): Coughing, hemoptysis, total pneumothorax

Frequency not reported: Shortness of breath, wheezing[Ref]


Common (1% to 10%): Chest tightness, diffuse chest pain, angina, palpitation, phlebitis

Frequency not reported: Blood pressure decrease, shock[Ref]


Common (1% to 10%): Arthralgia, long bones pain, localized and diffuse joint pain, edema of the legs

Frequency not reported: Rheumatic syndrome, systemic lupus erythematosus-like syndrome

Frequency not reported: Mild arthralgia, myalgia

Rare (less than 0.1%): Myopathy
Frequency not reported: Muscular weakness, pain in extremities[Ref]


Common (1% to 10%): Nausea, vomiting, digestive pain, diarrhea

Frequency not reported: Pancreatitis, nausea, vomiting, epigastric distress, constipation, dry mouth

Frequency not reported: Nausea, vomiting, peptic ulcer aggravation

Frequency not reported: Heartburn, epigastric distress, nausea, vomiting, flatulence, cramps, diarrhea, pseudomembranous colitis, abdominal discomfort, sore mouth, sore tongue[Ref]


Common (1% to 10%): Spiking fever, persistent fever

Frequency not reported: Fever

Rare (less than 0.1%): Malaise, fever

Very common (10% or more): "Flu" syndrome (episodes of fever, chills, headache, dizziness, bone pain; up to 50%)
Frequency not reported: Fatalities, fever, fatigue, edema of the face and extremities[Ref]


Frequency not reported: Gynecomastia

Rare (less than 0.1%): Adrenal insufficiency
Frequency not reported: Menstrual disturbances[Ref]


Frequency not reported: Dysuria[Ref]


Frequency not reported: Agranulocytosis, anemia (hemolytic, sideroblastic, aplastic), thrombocytopenia, eosinophilia

Rare (less than 0.1%): Thrombocytopenia with or without purpura, sideroblastic anemia with erythroid hyperplasia, vacuolation of erythrocytes, increased serum concentration, adverse effects on blood clotting mechanisms

Rare (less than 0.1%): Disseminated intravascular coagulation, agranulocytosis, hemolysis, hemoglobinuria, hematuria
Frequency not reported: Thrombocytopenia with or without purpura, leukopenia, hemolytic anemia, decreased hemoglobin, eosinophilia[Ref]


Frequency not reported: Anti-nuclear antibodies, lymphadenopathy[Ref]


Frequency not reported: Visual disorders

Frequency not reported: Visual disturbances, conjunctivitis[Ref]


Rare (less than 0.1%): Interstitial nephritis

Rare (less than 0.1%): Interstitial nephritis, acute tubular necrosis, renal insufficiency, acute renal failure
Frequency not reported: Elevated BUN[Ref]


Uncommon (0.1% to 1%): Toxic psychosis

Rare (less than 0.1%): Psychoses
Frequency not reported: Mental confusion, behavioral changes[Ref]


1. "Product Information. Rifater (isoniazid / pyrazinamide / rifampin)." SmithKline Beecham, Philadelphia, PA.

Some side effects of Rifater may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.