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The effects of paracetamol on frusemide ototoxicity
Abstract:
Paracetamol (acetaminophen) is currently one of the most widely used drugs. In large doses, paracetamol is both nephrotoxic and hepatotoxic, and this toxicity may arise through the production of free radicals. Recently, there has been a revival of interest in the hypothesis that aminoglycoside antibiotics are ototoxic because they facilitate free-radical production. Aminoglycosides interact strongly with loop diuretics, producing enhanced ototoxicity. The object of the present study was to determine whether paracetamol would also interact with a loop diuretic. Pigmented guinea pigs received a dose of 500 or 1000 mg/kg paracetamol via an intragastric cannula. Compound action potentials (CAP) were recorded every 10 min for 2 h. Paracetamol alone had no effect on CAP thresholds, but significantly enhanced the CAP decrement induced by frusemide given intraperitoneally 1 h after paracetamol. This enhancement was larger in animals receiving 1000 mg/kg paracetamol. Repetition of these drug doses in recovery experiments indicated that all threshold shifts recovered within 7 days.
Insights
Paracetamol (acetaminophen) alone does not affect hearing. However, it significantly worsens hearing loss caused by the loop diuretic frusemide, suggesting a potential drug interaction.
Area of Science:
- Pharmacology
- Toxicology
- Ototoxicology
Background:
- Paracetamol (acetaminophen) is a widely used analgesic and antipyretic.
- High doses of paracetamol can cause nephrotoxicity and hepatotoxicity, potentially via free radical production.
- Aminoglycoside antibiotics are known to be ototoxic, possibly due to free radical generation, and their ototoxicity is enhanced by loop diuretics.
Purpose of the Study:
- To investigate the potential interaction between paracetamol and a loop diuretic.
- To determine if paracetamol enhances the ototoxicity induced by loop diuretics.
Main Methods:
- Pigmented guinea pigs were administered paracetamol (500 or 1000 mg/kg) via intragastric cannula.
- Compound action potentials (CAP) were recorded to assess auditory function.
- The effect of paracetamol alone and in combination with intraperitoneally administered frusemide was evaluated.
Main Results:
- Paracetamol administered alone did not affect CAP thresholds.
- Paracetamol significantly enhanced the CAP decrement induced by frusemide.
- This enhancement of frusemide-induced ototoxicity was dose-dependent, being greater with 1000 mg/kg paracetamol.
- Auditory threshold shifts recovered within 7 days in recovery experiments.
Conclusions:
- Paracetamol interacts with the loop diuretic frusemide to enhance ototoxicity.
- This interaction may be relevant in clinical settings where patients are prescribed both paracetamol and loop diuretics.
- Further research is warranted to elucidate the mechanisms underlying this interaction, possibly involving free radical pathways.