What medication used in tuberculosis (TB) treatment causes discolored urine and saliva?

Rifampin Causes Orange-Red Discoloration of Body Fluids in Tuberculosis Treatment

Rifampin is the tuberculosis medication that causes orange-red discoloration of urine and saliva, which occurs in 100% of patients taking this medication. 1

Mechanism and Characteristics of Discoloration

• Rifampin causes predictable orange-red discoloration of multiple body fluids, including:

  • Urine
  • Saliva
  • Sweat
  • Tears
  • Sputum
  • Other secretions 1, 2

• The discoloration:

  • Begins shortly after starting therapy
  • Persists throughout the entire treatment course
  • Usually resolves within 24-48 hours after discontinuation 1
  • Is directly proportional to the amount of drug ingested 1

Clinical Significance

• This discoloration is benign and represents a cosmetic effect rather than a toxic reaction 1
• It does not indicate any harmful physiological process
• It serves as a useful marker for medication adherence, as healthcare providers can visually assess urine for orange/pink coloration to confirm patients are taking their rifampin-containing medications 1

Important Considerations for Patients

• Patients should be informed about this expected effect before starting treatment 1
• Rifampin can permanently stain soft contact lenses and clothing 1, 2
• The FDA label specifically states: "The patient should be told that rifampin may produce a discoloration (yellow, orange, red, brown) of the teeth, urine, sweat, sputum, and tears, and the patient should be forewarned of this." 2

Rifampin in TB Treatment

• Standard dosing for rifampin is 600 mg daily for adults (10 mg/kg/day) 1
• It is available in combination preparations:
  • Rifamate (rifampin + isoniazid)
  • Rifater (rifampin + isoniazid + pyrazinamide) 1
• Rifampin is never used alone for active TB treatment to prevent development of resistance 1

Other Important Rifampin Effects

• Rifampin induces hepatic enzymes, accelerating clearance of many drugs including:
  • Oral contraceptives
  • Warfarin
  • Methadone
  • Antiretrovirals 1
• Can cause hepatotoxicity, especially when combined with isoniazid 1

Comparison with Other TB Medications

• Rifabutin, another rifamycin used for TB treatment, also causes discolored urine but in only about 30% of patients compared to nearly 100% with rifampin 1
• Other first-line TB medications (isoniazid, ethambutol, pyrazinamide) do not cause this distinctive discoloration of body fluids

This distinctive orange-red discoloration of body fluids is a hallmark side effect of rifampin therapy that, while cosmetically concerning to patients, serves as a valuable indicator of medication adherence and does not represent a harmful physiological process.