What are the risks of using expired antibiotics (Antibacterial medications)?

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Last updated: February 25, 2025 • View editorial policy

From the Guidelines

Using expired antibiotics is strongly discouraged due to potential reduced effectiveness and increased risk of harm, as their chemical composition can degrade over time, leading to decreased potency and possible treatment failure. The risks associated with using expired antibiotics include decreased efficacy, potential toxicity, and contribution to antibiotic resistance 1.

Key Risks of Expired Antibiotics

  • Decreased potency: Expired antibiotics may not effectively combat bacterial infections, potentially leading to prolonged illness or treatment failure.
  • Toxicity: Certain antibiotics, such as tetracyclines, can develop toxic byproducts as they break down, which may cause harm, including kidney damage 1.
  • Antibiotic resistance: Using partially effective antibiotics can expose bacteria to suboptimal drug levels, allowing resistant strains to develop and contributing to the growing problem of antibiotic resistance 1.

Recommendations for Handling Expired Antibiotics

  • Dispose of expired antibiotics properly through medication take-back programs or by mixing them with unpalatable substances like coffee grounds before throwing them away.
  • Always store current antibiotics according to package instructions to maintain their effectiveness until their expiration date.
  • Consult a healthcare provider for a new prescription instead of using expired medications, as they can provide guidance on the most effective and safe treatment options 1.

From the Research

Risks of Using Expired Antibiotics

  • The use of expired antibiotics can lead to increased antibiotic resistance and clinical treatment failure, as well as adverse drug reactions 2
  • Expired antibiotics may have reduced potency, which can result in decreased efficacy and increased risk of treatment failure 2, 3
  • The use of expired antibiotics can also lead to the development of multiple antibiotic resistance, making it more difficult to treat infections 2

Specific Risks Associated with Expired Antibiotics

  • Higher total resistance and multiple antibiotic resistance rates have been recorded against expired antibiotics compared to unexpired antibiotics 2
  • Expired antibiotics may exhibit higher resistance rates against certain types of bacteria, such as E. coli, Klebsiella pneumoniae, Proteus mirabilis, and Staphylococcus aureus 2
  • The use of expired antibiotics can also lead to increased risk of adverse events, such as allergic reactions and disruptions to the gut microbiome 4

Storage and Expiration Dates

  • The storage conditions of antibiotics can affect their potency and efficacy, and expired antibiotics may still be effective if stored properly 3, 5
  • The expiration date of antibiotics may be safely extended for at least one year for most solid antibiotics, as long as they are stored under the right conditions 3

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.