Erythroprim: An Effective Antibiotic for a Range of Infections

When it comes to treating bacterial infections, Erythroprim is a reliable and effective choice. This antibiotic medication contains a combination of erythromycin and trimethoprim, which broadens its antimicrobial spectrum and covers a wide range of gram-negative and gram-positive bacteria. Let’s explore the composition, indications, side effects, precautions, and dosage guidelines for Erythroprim.


Erythroprim is available in two formulations: film-coated tablets and dry suspension. The composition of each is as follows:

  • Film-coated tablets:
    • Erythromycin stearate equivalent to Erythromycin base: 250 mg
    • Trimethoprim: 80 mg
  • Dry suspension:
    • Erythromycin ethyl succinate equivalent to Erythromycin base: 200 mg
    • Trimethoprim: 40 mg


The combination of erythromycin and trimethoprim in Erythroprim offers the following properties:

  • Broad antimicrobial spectrum: Erythroprim covers a wide range of gram-negative and gram-positive bacteria, making it effective against respiratory tract infections, gastroenteritis, urinary tract infections, E.N.T. infections, chlamydial infections, anaerobic infections, and other systemic infections caused by sensitive bacteria.
  • Delayed emergence of resistant strains: The combination of erythromycin and trimethoprim helps to delay the development of resistant bacterial strains.
  • Absorption and excretion: Erythroprim is well absorbed after oral administration and metabolized in the liver. Erythromycin is primarily excreted in bile, while trimethoprim is mainly excreted in urine.

Indications & Usage

Erythroprim is indicated for the treatment of the following conditions caused by susceptible organisms:

  • Respiratory tract infections: Upper and lower respiratory tract infections caused by organisms such as Staphylococcus, Streptococcus, Neisseria, Bordetella, Haemophilus influenzae, Corynebacteria, Legionella, and Klebsiella.
  • Gastroenteritis
  • Urinary tract infections
  • E.N.T. infections: Sinusitis and otitis media
  • Other systemic infections caused by sensitive bacteria
  • Chlamydial infections
  • Anaerobic infections

Side Effects

While Erythroprim is generally well-tolerated, it is important to be aware of potential side effects, including:

  • Erythromycin:
  • Infrequent and mild gastrointestinal upset
  • Allergic reactions in the form of skin rash
  • Trimethoprim:
  • Dose and course-related side effects such as nausea, vomiting, allergies, and fixed drug eruption
  • Rare cases of megaloblastic anemia and reversible bone marrow depression
  • Very rare hypersensitivity reactions

Drug Interactions

Erythroprim may interact with other medications, and it is important to be cautious when using it in combination with the following:

  • Erythromycin:
  • Potentiation of the effects of carbamazepine, corticosteroids, and digoxin
  • Concurrent use with theophylline may result in high and potentially toxic concentrations of theophylline
  • Competitive inhibition may occur when used concurrently with lincomycin, clindamycin, or chloramphenicol
  • Erythromycin may interfere with the bactericidal effect of penicillin
  • Trimethoprim:
  • Potentiation of the effects of warfarin
  • Increased side effects when used with other folic acid antagonizers

Warnings and Precautions

Before using Erythroprim, it is important to consider the following warnings and precautions:

  • Hypersensitivity: Do not use Erythroprim if you have a known hypersensitivity to either of the drugs.
  • G6PD deficiency: Individuals with G6PD deficiency should not use Erythroprim.
  • Pregnancy: Erythroprim should be avoided during pregnancy.
  • Dosage and Administration: The dosage of Erythroprim varies based on age and condition. It is important to follow the dosage guidelines provided by a healthcare professional.

In Conclusion

Erythroprim is a broad-spectrum antibiotic that combines erythromycin and trimethoprim to effectively treat a range of bacterial infections. With its broad antimicrobial spectrum and delayed emergence of resistant strains, Erythroprim provides reliable relief for respiratory tract infections, urinary tract infections, E.N.T. infections, and more. However, it is important to be aware of potential side effects and drug interactions associated with this medication. Always consult your healthcare professional for proper guidance and adhere to the prescribed dosage and administration instructions.

Disclaimer: This blog post is for informational purposes only and should not be considered a substitute for professional medical advice. Always consult your healthcare provider before starting any medication or treatment.

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