Gentamicin Injection and Ethacrynic Acid: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ethacrynic Acid
Gentamicin Injection
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased gentamicin plasma and tissue concentrations and additive ototoxicity
Interaction Deep Dive
Concomitant use of ethacrynic acid and gentamicin should be avoided1 due to potential additive ototoxicity. Concurrent administration of intravenous ethacrynic acid may increase gentamicin toxicity by altering gentamicin serum and tissue concentrations 2. If concurrent therapy is required, monitor for additive ototoxicity. Renal impairment may also enhance the incidence of ototoxicity 356.
Why it happens (mechanism)
Additive or synergistic toxicity
Literature reports
2 reports — tap to read
a) Two non-uremic patients experienced neurosensory hearing loss after the intravenous administration of ethacrynic acid. Both patients also received aminoglycoside antibiotics. In the first case, a 45-year-old female received gentamicin 60 mg intramuscularly every six hours and one dose of ethacrynic acid 50 mg. Within 15 minutes, she experienced total bilateral hearing loss and failed to response to shouting commands. Nine hours later, the hearing was subjectively normal. The second case involved a 64-year-old female who was receiving kanamycin 500 mg intramuscularly every 12 hours. She received two doses of ethacrynic acid 50 mg, separated by six hours. Within ten minutes of the second dose, she complained of total bilateral hearing loss which lasted six hours until she became comatose 3.
b) Three patients experienced permanent hearing loss following the administration of streptomycin and ethacrynic acid. Patient 1, a 24-year-old male, received streptomycin 4 grams over five days and two doses of ethacrynic acid 100 mg. After complaining of ringing in the ears, an audiometry demonstrated a bilateral 35- to 45-decibel sensorineural loss. Patient 2, a 35-year-old woman, was given ethacrynic acid 500 mg over a period of four days, along with streptomycin 1.5 grams. Although her hearing was normal prior to this event, an audiogram showed a bilateral sensorineural hearing loss of 70 decibels. The third patient experienced permanent deafness following the administration of ethacrynic acid 200 mg, streptomycin 3.5 grams, kanamycin 500 mg, and colonic irrigations of neomycin 15 grams. The Food and Drug Administration has also reported a case of permanent deafness following a single dose of kanamycin and ethacrynic acid 4.
Common questions
Can I take Gentamicin Injection and Ethacrynic Acid together?
Increased gentamicin plasma and tissue concentrations and additive ototoxicity Always confirm with your pharmacist or prescriber before making any change.
How serious is the Gentamicin Injection and Ethacrynic Acid interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Gentamicin Injection or Ethacrynic Acid need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (6)
- Product Information: EDECRIN(R) oral tablets, ethacrynic acid oral tablets. Merck & Co,Inc, Whitehouse Station, NJ, 2005. DailyMed
- Product Information: gentamicin injection, gentamicin injection. APP Pharmaceuticals LLC, Schaumburg, IL, 2008. DailyMed
- Meriwether WD, Mangi RJ, & Serpick AA: Deafness following standard intravenous dose of ethacrynic acid. JAMA 1971; 216:795-798. DOI
- Mathog RH & Klein WJ Jr: Ototoxicity of ethacrynic acid and aminoglycoside antibiotics in uremia. N Engl J Med 1969; 280:1223-1224. PubMed
- West BA, Brummett RE, & Himes DL: Interaction of kanamycin and ethacrynic acid. Severe cochlear damage in guinea pigs. Arch Otolaryngol 1973; 98:32-37. DOI
- Prazma J, Browder JP, & Fischer ND: Ethacrynic acid ototoxicity potentiation by kanamycin. Ann Otol Rhinol Laryngol 1974; 83:111-118. PubMed
Keep reading about Ethacrynic Acid
Keep reading about Gentamicin Injection
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