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Ototoxicity induced by gentamicin and furosemide
Duane E Bates1, Steve J Beaumont, Barry W Baylis
1Internal Medicine, Foothills Medical Centre, Calgary, Alberta, Canada. duane.bates@crha-health.ab.ca
Objective:
To present a case of ototoxicity induced by furosemide and once-daily gentamicin therapy.
Case Summary:
A 60-year-old white woman presented to the hospital with community-acquired pneumonia and urinary tract infection. The antibiotic regimen included gentamicin and, after 5 doses, the patient reported profound bilateral hearing loss. A Pure Tone Audiogram suggested moderate to moderately severe sensorineural hearing loss bilaterally. The only risk factors present included her age, elevated temperature, and the use of furosemide.
Discussion:
Several risk factors may predispose a patient to developing aminoglycoside ototoxicity: the 1555 chromosomal mutation, preexisting disorders of hearing and balance, hypovolemia, bacteremia, liver and renal dysfunction, and the simultaneous administration of other ototoxic medications. The cumulative dose and duration of aminoglycoside therapy are more important than serum concentrations. Administration of an aminoglycoside followed by furosemide may increase the risk of ototoxicity. The aminoglycoside interacts with the cell membranes in the inner ear, increasing their permeability. This theoretically allows the loop diuretic to penetrate into the cells in higher concentrations, causing more severe damage.
Conclusions:
Auditory toxicity occurred after only 5 days of gentamicin therapy and 1 dose of furosemide. An aminoglycoside followed by furosemide may increase the risk for ototoxicity. Clinicians need to be aware of the synergistic potential of ototoxic medications.
Insights
This case study highlights how gentamicin and furosemide combination therapy can cause rapid hearing loss. Even short-term use of these ototoxic medications poses a significant risk for auditory damage.
Area of Science:
- Ototoxicity
- Pharmacology
- Nephrology
Background:
- Aminoglycoside antibiotics, like gentamicin, are crucial for treating severe infections.
- Furosemide is a loop diuretic commonly used for fluid management.
- Ototoxicity is a known adverse effect of certain medications, including aminoglycosides.
Observation:
- A 60-year-old woman developed profound bilateral hearing loss after five days of once-daily gentamicin therapy.
- The patient also received a single dose of furosemide during her hospital stay.
- Audiogram confirmed moderate to moderately severe sensorineural hearing loss.
Findings:
- The combination of gentamicin and furosemide led to rapid and severe ototoxicity.
- Risk factors such as age and elevated temperature may have contributed.
- The synergistic effect of these ototoxic medications is a critical concern.
Implications:
- Clinicians must exercise caution when co-administering gentamicin and furosemide.
- Awareness of potential synergistic ototoxicity is vital for patient safety.
- This case underscores the importance of monitoring hearing function during treatment with ototoxic agents.