Isoniazid / Rifampin Side Effects

Medically reviewed by Drugs.com. Last updated on Apr 29, 2024.

Applies to isoniazid / rifampin: oral capsule.

Important warnings This medicine can cause some serious health issues

• This drug may cause very bad and sometimes deadly liver problems like hepatitis.

  Call your doctor right away if you have signs of liver problems like dark urine, feeling tired, not hungry, upset stomach or stomach pain, light-colored stools, throwing up, or yellow skin or eyes.

• The chance of liver problems is higher the older you are.

  The chance may also be raised by drinking alcohol every day, long-term liver problems, or injection drug use.

  The chance of liver problems may also be raised in women, mainly women who are black or Hispanic or who have just had a baby.

  Most of the time, liver problems caused by this drug happen within the first 3 months of care, but they can happen at any time.

  Most of the time, liver function has gone back to normal but sometimes it has not.

  Blood work will need to be done before starting this drug and while taking it.

  If you have questions, talk with the doctor.

• If you have active liver disease, talk with your doctor.

  This drug may not be right for you.

Serious side effects

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
• Signs of lupus like a rash on the cheeks or other body parts, sunburn easy, muscle or joint pain, chest pain or shortness of breath, or swelling in the arms or legs.
• Signs of a pancreas problem (pancreatitis) like very bad stomach pain, very bad back pain, or very bad upset stomach or throwing up.
• Signs of too much acid in the blood (acidosis) like confusion; fast breathing; fast heartbeat; a heartbeat that does not feel normal; very bad stomach pain, upset stomach, or throwing up; feeling very sleepy; shortness of breath; or feeling very tired or weak.
• Dizziness or passing out.
• Flu-like signs.
• Swollen gland.
• Joint pain or swelling.
• Muscle pain or weakness.
• Shortness of breath.
• Chest pain.
• Cough.
• Sweating a lot.
• A heartbeat that does not feel normal.
• Period (menstrual) changes.
• Fever, chills, or sore throat; any unexplained bruising or bleeding; or feeling very tired or weak.
• Purple spots or redness of the skin.
• A burning, numbness, or tingling feeling that is not normal.
• Seizures.
• Feeling confused, not able to focus, or change in behavior.
• Memory problems or loss.
• Change in eyesight, eye pain, or very bad eye irritation.
• Change in balance.
• Change in tooth color. These changes may be long-lasting.

Other side effects

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Change in color of body fluids to orange or red.
• Gas.
• Headache.
• Stomach pain or diarrhea.
• Heartburn.
• Stomach cramps.
• Upset stomach or throwing up.
• Feeling sleepy.
• Feeling tired or weak.
• Not hungry.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

For healthcare professionals

Applies to isoniazid / rifampin: oral capsule.

General adverse events

Doses greater than 600 mg of rifampin given once or twice weekly have resulted in a higher incidence of adverse reactions, including the "flu syndrome" (fever, chills, malaise); hematopoietic reactions (leukopenia, thrombocytopenia, acute hemolytic anemia); shortness of breath; shock; anaphylaxis; renal failure; and cutaneous, gastrointestinal, and hepatic reactions.^[Ref]

Cardiovascular

• Frequency not reported: Vasculitis

Rifampin:

• Frequency not reported: Flushing, decreased blood pressure^[Ref]

Dermatologic

• Frequency not reported: Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome, Stevens-Johnson syndrome, Toxic Epidermal Necrolysis (TEN), rash

Isoniazid:

• Frequency not reported: Acne, exfoliative dermatitis, pemphigus

Rifampin:

• Frequency not reported: Erythema multiforme, skin reaction, pruritus, pruritic rash, urticaria, allergic dermatitis, pemphigoid, sweat discoloration, cutaneous reactions^[Ref]

Endocrine

Isoniazid:

• Frequency not reported: Gynecomastia, hyperglycemia

Rifampin:

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

Gastrointestinal

• Frequency not reported: Nausea, vomiting, epigastric distress, diarrhea

Isoniazid:

• Frequency not reported: Constipation, dry mouth, pancreatitis

Rifampin:

• Frequency not reported: Gastrointestinal disorder, abdominal discomfort, heartburn, flatulence, cramps, pseudomembranous colitis, sore mouth, sore tongue^[Ref]

Hematologic

• Frequency not reported: Thrombocytopenia, eosinophilia, agranulocytosis, hemolytic anemia

Isoniazid:

• Frequency not reported: Anemia, aplastic anemia, lymphadenopathy

Rifampin:

• Uncommon (0.1% to 1%): Leukopenia
• Rare (less than 0.1%): Disseminated intravascular coagulation
• Frequency not reported: Decreased hemoglobin^[Ref]

Hepatic

• Frequency not reported: Hepatitis, elevated serum transaminases (SGOT, SGPT), bilirubinemia, bilirubinuria, jaundice

Rifampin:

• Common (1% to 10%): Elevated alkaline phosphatase
• Rare (less than 0.1%): Abnormal liver function, shock-like syndrome with hepatic involvement
• Frequency not reported: Hyperbilirubinemia^[Ref]

Hypersensitivity

Rifampin:

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

Metabolic

Isoniazid:

• Frequency not reported: Pellagra, pyridoxine deficiency, metabolic acidosis

Rifampin:

• Frequency not reported: Decreased appetite, anorexia^[Ref]

Musculoskeletal

Isoniazid:

• Frequency not reported: Systemic lupus erythematosus-like syndrome, rheumatic syndrome

Rifampin:

• Rare (less than 0.1%): Myopathy
• Frequency not reported: Muscle weakness, bone pain^[Ref]

Nervous system

Isoniazid:

• Common (1% to 10%): Peripheral neuropathy
• Uncommon (0.1% to 1%): Convulsions, toxic encephalopathy, optic neuritis and atrophy, memory impairment
• Frequency not reported: Vertigo, polyneuritis (presenting as paresthesia, muscle weakness, loss of tendon reflexes)

Rifampin:

• Frequency not reported: Headache, drowsiness, cerebral hemorrhage, ataxia, dizziness, inability to concentrate, muscular weakness, pains in extremities, generalized numbness^[Ref]

Peripheral neuropathy associated with isoniazid is dose-dependent, most often occurs in malnourished patients and in patients predisposed to neuritis (such as alcoholics and diabetics), and generally follows paresthesias of the hands and feet. The rate is higher in slow acetylators.^[Ref]

Ocular

Rifampin:

• Frequency not reported: Tear discoloration, visual disturbances, conjunctivitis^[Ref]

Other

• Frequency not reported: Fever

Isoniazid:

• Frequency not reported: Anti-nuclear antibodies

Rifampin:

• Frequency not reported: Influenza-like syndrome, post-partum hemorrhage, fetal-maternal hemorrhage, porphyria, edema, fatigue, facial edema, edema of the extremities, shock^[Ref]

Psychiatric

Isoniazid:

• Frequency not reported: Toxic psychosis

Rifampin:

• Frequency not reported: Psychotic disorder/psychoses, mental confusion, behavioral changes^[Ref]

Renal

Rifampin:

• Rare (less than 0.1%): Hemolysis, hemoglobinuria, hematuria, interstitial nephritis, acute tubular necrosis, renal insufficiency, acute renal failure
• Frequency not reported: Acute kidney injury, chromaturia, increased blood creatinine, elevated BUN, elevated serum uric acid^[Ref]

Respiratory

Rifampin:

• Frequency not reported: Dyspnea, wheezing, discolored sputum, shortness of breath^[Ref]

Further information

Isoniazid/rifampin side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

Medical Disclaimer