What antibiotic is used for Diphtheria?

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From the Guidelines

Benzathine penicillin or erythromycin are used to treat Diphtheria.

Treatment Options

  • Benzathine penicillin is administered as an IM injection of 600,000 units for persons less than 6 years old and 1,200,000 units for those greater than or equal to 6 years old 1
  • Erythromycin is given as a 7- to 10-day course of oral medication, with children receiving 40 mg/kg/day and adults receiving 1 g/day 1

Rationale

Erythromycin may be slightly more effective, but IM benzathine penicillin may be preferred due to avoiding possible noncompliance with a multi-day oral drug regimen 1.

Additional Considerations

In cases where the patient is infected with toxigenic Corynebacterium ulcerans, antibiotic treatment should follow clinical guidelines for patients infected with C. diphtheriae 1.

From the Research

Antibiotic Treatment for Diphtheria

The recommended first-line antibiotics for the treatment of diphtheria are:

  • Penicillin
  • Erythromycin 2, 3 These antibiotics are used in conjunction with diphtheria antitoxin to limit morbidity and reduce the duration of infection 4, 5.

Antibiotic Susceptibility

Studies have shown that the susceptibility pattern of Corynebacterium diphtheriae to erythromycin is better than that to penicillin 3.

  • 85.2% of isolates were susceptible to erythromycin, with a MIC range of <0.016 to >256 μg/L
  • 68.52% of isolates were susceptible to penicillin, with a MIC range of <0.016 to 2 μg/L 3

Importance of Antibiotic Treatment

Antibiotic treatment, in combination with diphtheria antitoxin, is essential for reducing the duration of infection and limiting morbidity 4, 5. The use of antibiotics, such as penicillin and erythromycin, can help to reduce the transmission of diphtheria and prevent outbreaks 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Clinical and Epidemiological Aspects of Diphtheria: A Systematic Review and Pooled Analysis.

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2020

Research

Access to diphtheria antitoxin for therapy and diagnostics.

Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin, 2014

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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