Medications and vitamins associated with foul-smelling urine
B-complex vitamins (especially riboflavin) are associated with urine that can smell fishy or musty. [1]
Methenamine decomposes in urine to formaldehyde and ammonia, which can be associated with a strong/unpleasant urine odor (often ammonia-related). [3]
Certain vitamins and some medication classes can change urine odor without necessarily indicating infection. [2], [4]
Vitamin and supplement agents
- B-complex vitamins (including riboflavin/B2) can cause urine to become bright yellow and can make urine smell fishy or musty. [1]
- Vitamin B6 (pyridoxine) is specifically noted as contributing to a musk-like odor in urine. [4]
- Vitamin C (ascorbic acid) is associated with urine color changes and may coincide with altered urine odor. [1], [2], [4]
Medication agents
- Methenamine is excreted in urine and decomposes at acidic urine pH into formaldehyde and ammonia, which is a pharmacologic basis for an unpleasant/strong urine odor. [3]
- Some chemotherapy drugs are associated with characteristic urine odor changes. [4]
Mechanistic considerations for odor changes
- Concentrated urine can produce a strong ammonia-related odor. [2]
- Vitamins can be excreted in urine and may directly alter urine odor. [2], [1]
Clinical context and clarification
- Odor changes are also commonly caused by genitourinary infection or other metabolic conditions, and foul-smelling urine can be a sign of bacterial involvement. [5], [2]
Practical assessment triggers
- Persistent foul-smelling urine should be evaluated for infection or other causes, particularly when accompanied by dysuria, frequency, fever, or hematuria. [5], [2]
End with last clinical topic: persistent odor changes should prompt evaluation for infection or metabolic causes.