Answer
Rifampicin and its coloured breakdown products enter body fluids. Orange-red urine, tears, saliva, sweat and sputum are expected and usually harmless, but soft contact lenses may stain permanently.
Sources for this answer
- NHSNHS · NHS medicine guidance
- Rifadin 100mg/5ml Oral Suspension — Current selected SmPCemc · Summary of Product Characteristics
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.