Can Flagyl (metronidazole) cause hearing loss?

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Last updated: June 19, 2025View editorial policy

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From the Research

Metronidazole (Flagyl) is not typically associated with hearing loss as a common side effect, but rare cases of ototoxicity have been reported, as seen in a case study from 1999 1. While this medication can cause various side effects such as nausea, metallic taste, headache, and peripheral neuropathy with prolonged use, ototoxicity (damage to the ear causing hearing loss) is not a well-established adverse effect of metronidazole. If you're experiencing hearing changes while taking metronidazole, you should contact your healthcare provider promptly as this could be related to another cause or possibly a rare reaction. Other antibiotics, particularly aminoglycosides (like gentamicin), certain macrolides, and vancomycin, are more commonly associated with ototoxicity. The standard dosing of metronidazole (typically 500 mg three times daily for 7-14 days for most infections) has not been linked to hearing problems in clinical studies or post-marketing surveillance, as discussed in a review of metronidazole's therapeutic uses and side effects from 2019 2. Some key points to consider include:

  • Metronidazole is generally well-tolerated with mild to moderate side effects such as nausea, abdominal pain, and diarrhea.
  • Serious neurotoxicity, optic neuropathy, peripheral neuropathy, and encephalopathy have been reported in rare cases, as noted in a study on neurologic complications of metronidazole from 2013 3.
  • If you have pre-existing hearing issues or are taking other medications that might affect hearing, it's especially important to discuss any concerns with your doctor before starting or continuing metronidazole therapy. In terms of the risk of hearing loss, a study from 1999 1 reported two cases of bilateral moderate to severe sensorineural hearing loss due to oral administration of metronidazole, highlighting the need for awareness of this potential side effect. However, it's essential to weigh this risk against the benefits of metronidazole therapy, as the medication is effective against various infections, including trichomoniasis, amoebiasis, and giardiasis, as discussed in a review of metronidazole's therapeutic uses from 2019 2. Ultimately, if you're experiencing hearing changes while taking metronidazole, you should contact your healthcare provider promptly to rule out any potential causes and discuss the best course of action.

References

Research

Metronidazole ototoxicity--report of two cases.

The Journal of laryngology and otology, 1999

Research

Therapeutic uses of metronidazole and its side effects: an update.

European review for medical and pharmacological sciences, 2019

Research

Neurologic complications of metronidazole.

The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques, 2013

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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