Wait... Shouldn't that be Yellow? - OnePoint Patient Care

Wait… Shouldn’t that be Yellow?

A Quick Overview of the Causes of Urinary Discoloration

Terminally ill patients may experience a variety of changes and new symptoms as the end of life approaches. Urinary symptoms may be especially troublesome for patients, family members, caregivers, and clinicians. Hospice patients commonly experience incontinence, retention, and decreased output. Another distressing change that patients may experience is abnormal urine color.

Variation in urine color or appearance is often due to an underlying medical condition. Additionally, ingesting certain medications, foods, or dyes can also cause affect urine’s appearance.1 The good news is that when this happens, it’s usually benign.1,2 Unusual urine color associated with medications or diet should resolve on its own once the drug, food, or dye is no longer consumed. Medications and conditions associated with abnormal urine color or appearance are provided in table 1.

Table 1: Urine Color / Appearance 1-11


Notably, purple urine isn’t known to be caused by any foods or medications. Instead, it’s likely indicative of purple urine bag syndrome, a benign condition associated with chronic catheter use.1 It’s caused by bacteria in the urine that break down dietary tryptophan metabolites into indigo, a blue pigment, and indirubin, a red pigment. These pigments then combine to form purple urine that stains the urine bag and catheter.1,3-5

Urine color is a subjective observation, so some may describe colors differently. For example, red urine might appear to some as pink, orange, brown, or black.3 Additionally, colorblindness is not uncommon and since color is in the eye of the beholder, it would be reasonable to consider medications or causes that might be associated with similar urine colors.

Consider preemptively educating patients and caregivers about the potential for urinary discoloration when the above drugs are ordered. Setting the expectation that this could happen and providing reassurance that it’s not harmful could go a long way to prevent unnecessary stress, anxiety, and worry.

Written By:

John Corrigan, PharmD

Clinical Pharmacist, OnePoint Patient Care


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  2. Meng Q, Handay B, Wagar, E. It’s Not Easy Being Blue-green. Ann Lab Med. 2013;33:457-458. doi:10.3343/alm.2013.336.457
  3. Foot C, Fraser J. Uroscopic Rainbow: Modern Matula Medicine. Postgrad Med J. 2006;82:126-129. doi: 10.1136/pgmj.2005.037598
  4. Charlesworth S, ed. Palliative Care Formulary: Edition 7. 7th ed. Pharmaceutical Press; 2020.​
  5. Burg M, Baerends E, Bell C H. Unusual Urine Color During Catheterization. Am Fam Physician. 2016;94(7):572-574
  6. Schaffer AC. Urinalysis and Urine Electrolytes. In: Mckean SC, Ross JJ, Dressler DD, Scheurer DB. eds. Principles and Practice of Hospital Medicine, 2e. McGraw-Hill; 2017.Accessed March 23, 2021.
  7. Viswanathan S. Urine Bag as a Modern Day Matula. ISRN Nephrology. 2013:1-8. doi:10.5402/2013/215690
  8. Revollo J, Lowder J, Pierce A, Twilla J. Urine Discoloration Associated with Metronidazole. J Pharm Tenol. 2014;30(2):54-56. doi:10.1177/8755122513500921
  9. Urine Discoloration. Global RPh. Accessed March 23,2021. https://globalrph.com/drugs/urine-discoloration
  10. Lexi-Drugs. Lexicomp. Wolters Kluwer Health, Inc. Accessed March 24, 2021.
  11. MacGill, M. Why is my Urine Bright Yellow?. Medical News Today. July 24, 2018. Accessed April 1, 2021. https://www.medicalnewstoday.com/articles/313779