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Does rifampin turn urine orange?


Yes, rifampin often causes orange discoloration of urine. Rifampin is an antibiotic that is used to treat several types of bacterial infections, including tuberculosis, methicillin-resistant Staphylococcus aureus (MRSA), and Legionnaires’ disease. It belongs to a class of antibiotics called rifamycins. Rifampin works by binding to and inhibiting bacterial DNA-dependent RNA polymerase, which prevents RNA transcription and protein synthesis in bacteria. This leads to bacterial cell death. One of the most common side effects of taking rifampin is orange-colored urine, sweat, tears, and other bodily fluids. This harmless discoloration is caused by rifampin metabolites that are excreted through urine. It does not require treatment or indicate any medical problems. The orange color should go away after discontinuing rifampin.

How does rifampin cause orange urine?

Rifampin causes orange urine because it contains a red-orange aromatic compound. When ingested, around 6-25% of rifampin gets metabolized by the body into a brightly colored orange chemical called rifampicin quinone. This metabolite is then filtered out of the blood by the kidneys and excreted in urine, which gives urine an orange or reddish-orange tint. The intensity of the color can vary based on the dose and individual factors. Sometimes it can look dark orange, reddish, or slightly rusty. The orange color does not pose any health risks and will disappear once you finish the course of rifampin treatment. It does not require any intervention.

What percentage of people on rifampin develop orange urine?

Studies show that around 60-80% of people taking rifampin will notice some degree of urine discoloration. However, the prevalence may be even higher since subtle changes in urine color can be missed. One study that objectively measured urine color found that 100% of participants taking 450-600 mg of rifampin daily developed abnormal orange urine by the end of two weeks. So it is very common to experience orange urine while on rifampin, but the intensity of color change can vary between individuals. Factors like dosage, duration of therapy, and individual differences in drug metabolism contribute to these variations.

When does the orange color appear and disappear?

The orange discoloration of urine can begin as early as a few hours after the first dose of rifampin. Many people notice the orange color within 1-2 days of starting treatment. The urine tends to become darker and more intensely orange as therapy continues, but the maximum intensity is usually reached between 3 days to 2 weeks. After stopping rifampin, the orange color fades over a period of 1-2 weeks as the drug is eliminated from the body. However, it can occasionally last for up to 4 weeks after discontinuation. temporary orange discoloration.

Can other bodily fluids turn orange too?

Yes, rifampin can also cause orange coloration of other bodily fluids such as sweat, tears, sputum, and saliva in some people. This occurs due to the same metabolites being excreted through these fluids.

The most commonly affected are:

– Sweat – Orange sweat is seen in around 14-23% of people on rifampin. It is more visible when sweating profusely.

– Tears – Orange tears occur in up to 15% of people.

– Saliva – Orange spit/sputum is less common but can occur.

– Semen – Rarely, orange/brown discoloration of semen has been reported.

– Feces – In some cases, feces can turn a reddish hue.

So rifampin can give an orange tinge to many bodily secretions, but urine is most prominently affected in most people.

Is orange urine a cause for concern?

Orange discoloration of urine due to rifampin is harmless and temporary. It does NOT indicate any problems with liver function or kidney function. The orange color is simply due to the rifampin metabolite that gets filtered out in urine. No specific treatment is needed other than continuing antibiotics as prescribed by your doctor. However, if you notice very dark urine along with symptoms like nausea, fatigue, or abdominal pain, be sure to call your doctor. Dark urine can result from dehydration, which impairs excretion of the orange pigment. In rare cases, it could signal liver toxicity, which requires prompt medical attention. Otherwise, orange urine is expected and not a cause for alarm while taking rifampin.

Can the orange color transfer to contact lenses?

Yes, the orange pigment can accumulate on contact lenses in some users of rifampin. Tiny amounts of the metabolite present in tears can get deposited onto contact lenses, especially with extended wear. This can result in an orange tinge or discoloration of the contacts. To prevent staining, it is recommended to switch to glasses during rifampin treatment or use daily disposable contact lenses that can be replaced regularly. Hydrogel lenses and silicone hydrogel lenses may get stained less than soft lenses. Proper daily cleaning and enzymatic contact lens solutions can also help reduce staining. The orange discoloration should resolve once the antibiotic course is complete.

Does the dose of rifampin affect the orange color?

Yes, higher doses of rifampin usually produce a more intense orange coloration of urine. This is because more of the drug is metabolized into the orange quinone compound that gets excreted. Doses of 600-1200 mg daily often cause dark orange urine, while lower doses may result in lighter orange urine. However, there can be individual variability as well. In general, the urine color correlates with the blood concentration of rifampin. So larger doses and higher levels in blood lead to more orange pigment being filtered out in the urine. The orange color should not be used to judge the effectiveness of therapy and does not require a change in medication dosage.

Can other antibiotics cause similar orange discoloration?

Rifampin is one of the most well-known causes of orange bodily fluids. However, some other antibiotics may rarely cause similar discoloration in high doses. These include:

– Fluoroquinolones like ciprofloxacin – can uncommonly cause orange or red urine at very high doses.

– Nitrofurantoin – used for urinary tract infections, can rarely cause urine to appear brown, orange, or red.

– Metronidazole – an anti-parasitic drug that may infrequently cause orange urine at high doses.

However, rifampin is the most likely medication to turn urine orange. None of these other drugs do so as frequently or noticeably as rifampin. The orange color should resolve after stopping the antibiotic.

Can certain foods or medications increase the orange color?

Yes, certain foods and drugs can potentially increase the intensity of orange discoloration caused by rifampin. This includes:

– Carotene-rich foods – Fruits and vegetables high in carotenes like carrots, sweet potatoes, squash, and spinach can add to the orange color.

– Vitamin B2 (riboflavin) – Large doses of riboflavin can give urine a fluorescent yellow-orange color when taking rifampin.

– Phenazopyridine – A urinary analgesic that can turn urine orange even without rifampin. The combination intensifies the color.

– Laxatives like senna or rhubarb – Contain anthraquinone that can give urine an orange-red tint.

However, rifampin alone is enough to cause orange discoloration without any external factors. These may only make the existing coloration more intense. The effect should subside once rifampin is stopped.

Does orange urine affect lab test results?

The orange color can potentially interfere with the interpretation of some urine tests and levels:

– Urine bilirubin levels may be falsely elevated due to spectral interference by the orange pigment. Orange urine does NOT indicate liver problems or increased bilirubin.

– Urinalysis testing strips read the urine color visually. Orange urine may cause confusion in judging parameters like blood, protein, leukocytes, or ketones.

– Orange color can interfere with spectrophotometric measurements of urine urobilinogen and porphyrin levels.

To prevent errors, the lab should be informed about the discoloration caused by rifampin. Bilirubin levels and urine test strips may need to be double-checked using an alternate method not affected by orange pigment.


In summary, the vast majority of people taking rifampin will notice temporary orange discoloration of their urine, and possibly sweat, tears and other fluids. This harmless side effect is caused by a rifampin metabolite that gets filtered out by the kidneys. The orange color tends to intensify within the first 1-2 weeks and fades over 1-4 weeks after stopping the antibiotic. No treatment is required beyond staying well hydrated. Orange urine does not indicate any medical problems and should not cause alarm while on rifampin therapy. Being aware of this expected side effect prevents unnecessary worry.