Can Metronidazole Change Urine Color?
In our latest question and answer, the pharmacist discusses whether or not metronidazole (Flagyl) can change the color of your urine.
Can metronidazole change your urine color? Mine is a darker color than usual.
Aug 23, 2022- Metronidazole commonly causes urine to become darker than usual, which is a normal side effect of the medication.
- Dark urine from metronidazole should return to its normal color within a day or two after you stop taking the medication.
- Never take metronidazole with alcohol or alcohol-containing products, as this can cause serious side effects like vomiting, rapid heart rate, and abdominal cramps.
Answer
Flagyl (metronidazole) is both an antibacterial as well as an antiprotozoal agent. One of the most common side effects of metronidazole is urine discoloration, which commonly manifests as a darker than usual color.
Metronidazole is commonly prescribed to treat many types of skin infections, lower respiratory tract infections, and vaginal infections. Because metronidazole is effective against a variety of pathogens, it is widely used both as monotherapy (i.e. alone) as well as in combination with other medications.
Metronidazole Side Effects
Common side effects of metronidazole include but are not limited to:
- Urine discoloration/dark urine
- Headache
- Diarrhea
- Metallic taste
- Nausea
- Upset stomach
Metronidazole can be taken with or without food but should never be taken with any type of ethanol (including alcoholic beverages and common cough medications). If ethanol-containing substances are ingested while taking metronidazole, side effects can be severe and include:
- Vomiting
- Nausea
- Headache
- Rapid heart rate
- Flushing
- Abdominal cramps
Ethanol-containing products should not be ingested for up to three days after completing a course of metronidazole to avoid these effects.
Final Words
Thanks again for your question!
Metronidazole is cleared fairly quickly from your system, so if you have noticed a change in urine color due to the medication, it should go back to its usual color within a day or two at the latest.
References & sources
- Flagyl Prescribing Information — Pfizer
Glossary — Terms in This Answer
- Antibacterial
- A medication that kills or stops the growth of bacteria.
- Antiprotozoal
- A medication that kills or stops the growth of protozoans, which are tiny single-celled parasites.
- Urine discoloration
- An unwanted change in the normal color of urine.
- Lower respiratory tract infections
- Infections in the lungs and lower airways that carry air to the lungs.
- Pathogens
- Disease-causing organisms such as bacteria, viruses, or parasites.
- Monotherapy
- Treatment using a single medication alone rather than combined with other drugs.
- Ethanol
- The type of alcohol found in alcoholic beverages and some medicines.
- Abdominal cramps
- Sudden sharp or tight pain in the stomach and belly area.
Dr. Brian Staiger, PharmD
Doctor of Pharmacy, board certified clinical pharmacist (BCPS), American Herbalist Guild, Medication Therapy Management certified
Brian Staiger, PharmD, BCPS, is a licensed pharmacist with more than 13 years of experience across retail pharmacy, clinical pharmacy, medication safety, pharmacy program development, and healthcare administration. He is the founder of HelloPharmacist.com, where he helps patients...
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