What tuberculosis (TB) medication causes orange urine?

Rifampin Causes Orange Urine in TB Treatment

Rifampin is the tuberculosis medication that causes orange discoloration of urine and other body fluids. 1 This discoloration is a well-documented and expected side effect that occurs in virtually all patients taking the medication.

Mechanism and Characteristics

• Rifampin is excreted in urine, tears, sweat, and other body fluids, coloring them orange 2
• The discoloration begins shortly after starting therapy and persists throughout the entire course of treatment
• The intensity of the color is directly proportional to the amount of drug ingested, which makes it a useful marker for medication adherence 1
• The orange discoloration typically resolves within 24-48 hours after discontinuation of the drug 1

Clinical Significance

• The orange discoloration of urine is benign and represents a cosmetic effect rather than a toxic reaction 1
• This effect does not indicate any harmful physiological process but can be alarming to patients if they are not informed beforehand
• The standard dosing for rifampin is 600 mg daily for adults (10 mg/kg/day) 1
• Rifampin is never used alone for active TB treatment to prevent development of resistance 1

Patient Education Points

1. Patients should be advised before starting treatment that rifampin will cause orange discoloration of urine, sweat, tears, and other body fluids 3
2. Patients should be warned that rifampin can permanently stain soft contact lenses 2, 3
3. Clothing may also become stained from body fluids containing rifampin 1
4. The orange urine is not harmful and does not indicate toxicity 1

Other Rifamycins and Similar Effects

• Rifabutin, another rifamycin used for TB treatment, also causes discolored urine, though this occurs in about 30% of patients compared to nearly 100% with rifampin 4
• Both rifampin and rifabutin have similar mechanisms of action and share many side effects, including the potential for discoloration of body fluids 2

Clinical Monitoring Considerations

• The distinctive color change in urine serves as a useful visual marker for medication adherence 1
• Healthcare providers can visually assess or laboratory-test urine for orange/pink coloration to confirm that patients are taking their rifampin-containing medications 1
• No specific monitoring is required for the discoloration itself, but standard monitoring for rifampin therapy should continue as recommended, including liver function tests 1

The orange discoloration of urine and other body fluids is a characteristic and predictable effect of rifampin therapy that, while cosmetically concerning to patients, serves as a useful indicator of medication adherence in tuberculosis treatment.