Diphtheria Medication

Updated: Aug 17, 2022
  • Author: Bruce M Lo, MD, MBA, RDMS, FACEP, FAAEM, FACHE, FAAPL, CPE; Chief Editor: Jeter (Jay) Pritchard Taylor, III, MD  more...
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Medication Summary

Patients with active disease as well as all close contacts should be treated with antibiotics. Treatment is most effective in the early stages of disease and decreases the transmissibility and improves the course of diphtheria. Additionally, close contacts, such as family members, household contacts, and potential carriers, must receive chemoprophylaxis regardless of immunization status or age. This entails treatment with erythromycin or penicillin for 14 days and post treatment cultures to confirm eradication. [4]

The CDC has approved macrolides such as erythromycin as first-line agents for patients older than 6 months of age. However, macrolide therapy has been associated with an increase in pyloric stenosis in children younger than 6 months, especially treatment with erythromycin. Intramuscular penicillin is recommended for patients who will be noncompliant or intolerant to an erythromycin course.

The horse serum antitoxin is given to anyone suspected to have diphtheria and can be administered without confirmation from cultures, as it is most efficacious early during the course of the disease.

Diphtheria antitoxin can be obtained only from the CDC. For more information regarding acquisition, see the CDC website for diphtheria antitoxin.



Class Summary

Diphtheria antitoxin was first used in the United States in 1891, derived from a horse serum, it neutralizes unbound exotoxin. It is to be administered as soon as diphtheria suspected. It can only be obtained from the CDC and is not available internationally. Administer immunization toxoid booster, as the antitoxin does not influence immunity.

Diphtheria antitoxin

Neutralizes toxin before it enters cells. Dose given depends on site of infection and length of time patient is symptomatic. In United States, diphtheria antitoxin (DAT) is available from the CDC. Contact a diphtheria duty officer through CDC’s Emergency Operations Center at 770-488-7100. Report all suspected cases of diphtheria to local and state health departments.



Class Summary

Erythromycin and penicillin are both recommended for the treatment of diphtheria. Some studies suggest that erythromycin may be better at eradication of the carrier state. Penicillin is recommended in household contacts who may not comply with the duration of erythromycin treatment. An increased incidence of pyloric stenosis is associated with administration of erythromycin to infants younger than 6 months. It is believed that azithromycin may be a better macrolide treatment in this population, though there are a few case reports describing pyloric stenosis in infants treated with azithromycin for pertussis infections.

The treatment of endocarditis requires the addition of an aminoglycoside.

Erythromycin (E-Mycin, Ery-Tab)

Inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes causing RNA-dependent protein synthesis to arrest. For treatment of staphylococcal and streptococcal infections.

Age, weight, and severity of infection determine proper dosage in children. When bid dosing is desired, one half the total daily dose may be taken q12h. Double the dose for more severe infections.

Has the added advantage of being a good anti-inflammatory agent by inhibiting migration of polymorphonuclear leukocytes.


Antibiotic, Penicillin

Class Summary

Penicillin may be used for treatment, prophylaxis, and eradication of diphtheria in carriers. However, resistant strains and transmission from penicillin-treated carriers has been reported.

Penicillin G benzathine (Bicillin L-A, Permapen)

Interferes with synthesis of cell wall mucopeptides during active multiplication, which results in bactericidal activity. Effective treatment for systemic diphtheria.