UMEM Educational Pearls



A 7 year-old Spanish speaking female presents to the emergency room after ingestion of 2 – 3 tablets of her sister’s medication. She complains of nausea/vomiting with diarrhea, periorbital/facial swelling, and flushing of her skin. Her urine is reddish but there is no blood is shown in urinalysis/urine microscopic analysis. The patient's sister is taking the medication for a respiratory condition.


Which medication did she take?



Rifampin is often used to treat tuberculosis as part of a combination therapy. It inhibits RNA chain polymerization in mycobacteria. Rifampin also has significant drug-drug interaction issue due to induction of CYP3A4, 1A2, 2C9 and 2C19.

Isolated rifampin ingestion infrequently leads to serious toxicity.

Common symptoms of acute toxicity include:

  1. GI: nausea/vomiting and diarrhea
  2. Skin: facial/periorbital swelling in children, and angioedema
  3. Neurologic: numbness, extremity pain, ataxia, muscle weakness
  4. Red-orange discoloration of bodily fluids

Chronic toxicity

  1. Hepatitis when co-administered with INH
  2. Hypersensitivity reaction:
    • Viral syndrome like condition: fever, chills, myalgia
    • Hemolytic anemia, thrombocytopenia, eosinophilia
    • Interstitial nephritis and acute kidney injury


Management of acute toxicity is mainly supportive.