Erythromycin; Uses, Dosage, Side Effects, Drug Interactions

Last updated: February 7, 2026Reviewed date: February 7, 2026Reading time: 8 min read
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Erythromycin is a broad-spectrum, macrolide antibiotic with antibacterial activity. Erythromycin diffuses through the bacterial cell membrane and reversibly binds to the 50S subunit of the bacterial ribosome. This prevents bacterial protein synthesis. Erythromycin may be bacteriostatic or bactericidal in action, depending on the concentration of the drug at the site...

For severe symptoms, danger signs, pregnancy, child illness, or sudden worsening, seek urgent medical care.

বাংলা রোগী নোট এখনো যোগ করা হয়নি। পোস্ট এডিটরে “RX Bangla Patient Mode” বক্স থেকে সহজ বাংলা সারাংশ যোগ করুন।

এই তথ্য শিক্ষা ও সচেতনতার জন্য। এটি ডাক্তারি পরীক্ষা, রোগ নির্ণয় বা প্রেসক্রিপশনের বিকল্প নয়।

Article Summary

Erythromycin is a broad-spectrum, macrolide antibiotic with antibacterial activity. Erythromycin diffuses through the bacterial cell membrane and reversibly binds to the 50S subunit of the bacterial ribosome. This prevents bacterial protein synthesis. Erythromycin may be bacteriostatic or bactericidal in action, depending on the concentration of the drug at the site of infection and the susceptibility of the organism involved. Erythromycin is a bacteriostatic antibiotic macrolide produced by Streptomyces erythreus. Erythromycin...

Key Takeaways

  • This article explains Mechanism of Action of Erythromycin  in simple medical language.
  • This article explains Indications of Erythromycin  in simple medical language.
  • This article explains Contra-Indications of Erythromycin  in simple medical language.
  • This article explains Dosage of Erythromycin  in simple medical language.
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Emergency safety firstUrgent warning signs are highlighted below.

Seek urgent medical care if you notice

These warning signs are general safety guidance. Local emergency numbers and clinical judgment should always come first.

  • Severe symptoms, breathing difficulty, fainting, confusion, or rapidly worsening illness.
  • New weakness, severe pain, high fever, or symptoms after a serious injury.
  • Any symptom that feels urgent, unusual, or unsafe for the patient.
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Definition

Erythromycin is a broad-spectrum, macrolide bacterial infections. সহজ বাংলা: ব্যাকটেরিয়ার সংক্রমণের ওষুধ।" data-rx-term="antibiotic" data-rx-definition="An antibiotic is a medicine used to treat bacterial infections. সহজ বাংলা: ব্যাকটেরিয়ার সংক্রমণের ওষুধ।">antibiotic with antibacterial activity. Erythromycin diffuses through the bacterial cell membrane and reversibly binds to the 50S subunit of the bacterial ribosome. This prevents bacterial protein synthesis. Erythromycin may be bacteriostatic or bactericidal in action, depending on the concentration of the drug at the site of infection and the susceptibility of the organism involved.

Erythromycin is a bacteriostatic bacterial infections. সহজ বাংলা: ব্যাকটেরিয়ার সংক্রমণের ওষুধ।" data-rx-term="antibiotic" data-rx-definition="An antibiotic is a medicine used to treat bacterial infections. সহজ বাংলা: ব্যাকটেরিয়ার সংক্রমণের ওষুধ।">antibiotic macrolide produced by Streptomyces erythreus. Erythromycin A is considered its major active component. Insensitive organisms, it inhibits protein synthesis by binding to 50S ribosomal subunits. This binding process inhibits peptidyl transferase activity and interferes with translocation of amino acids during translation and assembly of proteins.

It inhibits bacterial protein synthesis by binding to bacterial 50S ribosomal subunits; binding inhibits peptidyl transferase activity and interferes with translocation of amino acids during translation and assembly of proteins. Erythromycin may be bacteriostatic or bactericidal depending on the organism and drug concentration.

Mechanism of Action of Erythromycin 

Erythromycin acts by penetrating the bacterial cell membrane and reversibly binding to the 50 S subunit of bacterial ribosomes or near the “P” or donor site so that binding of tRNA (transfer RNA) to the donor site is blocked. Translocation of peptides from the “A” or acceptor site to the “P” or donor site is prevented, and subsequent protein synthesis is inhibited. Erythromycin is effective only against actively dividing organisms. The exact mechanism by which erythmromycin reduces lesions of acne vulgaris is not fully known: however, the effect appears to be due in part to the antibacterial activity of the drug.

Indications of Erythromycin 

  • Acne vulgaris
  • Bacterial infections
  • Upper respiratory tract infection
  • Dental abscess
  • Bacterial endocarditis prevention
  • Skin or soft tissue infection
  • Bartonellosis
  • Bowel preparation
  • Bronchitis
  • Bullous pemphigoid
  • Campylobacter gastroenteritis
  • Legionella pneumonia
  • Lymphogranuloma venereum
  • Mycoplasma pneumonia
  • Nongonococcal urethritis
  • Ocular rosacea
  • Otitis media
  • Pemphigoid
  • Pertussis
  • Pharyngitis
  • Pneumonia
  • Rheumatic fever prophylaxis
  • Strep throat
  • Chlamydial ophthalmia neonatorum
  • Community acquired pneumonia
  • Gastroparesis
  • Granuloma inguinale
  • Intestinal amebiasis caused by entamoeba histolytica
  • Legionella pneumophila infections
  • Lower respiratory tract infection
  • Lymphogranuloma venereum
  • Ophthalmia neonatorum (gonococcal)
  • Postoperative Infections
  • Primary syphilis
  • Staphylococcal skin Infections
  • Ureaplasma urethritis
  • Skin and subcutaneous tissue bacterial infections caused by streptococcus pyogenes
  • Superficial ocular infections

Contra-Indications of Erythromycin 

  • Clostridium difficile infection
  • Myasthenia gravis
  • Hearing loss
  • Very rapid heartbeat – torsades de Pointes
  • prolonged QT interval on EKG
  • Abnormal EKG with QT changes from birth
  • Liver problems
  • Abnormal liver function tests
  • infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">Inflammation of the liver with stoppage of bile flow

Dosage of Erythromycin 

Campylobacter Gastroenteritis

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.
  • Severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

Chancroid

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.
  • Severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

Lymphogranuloma Venereum

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.
  • Severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

Mycoplasma Pneumonia

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.
  • Severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

Mycoplasma Pneumonia

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.
  • Severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

Nongonococcal Urethritis

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.
  • Severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

Otitis Media

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.

Severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

 Pharyngitis

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.
  • Severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

Pneumonia

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.
  • Severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

Soft Tissue Infection

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.
  • Severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

Syphilis – Early

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.
  • Severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

Upper Respiratory Tract Infection

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.
  • severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

Bronchitis

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.
  • Severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

Chlamydia Infection

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.
  • Severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

Lyme Disease

  • Mild to moderate infection: 250 to 500 mg (base, estolate, stearate) or 400 to 800 mg (ethylsuccinate) orally every 6 hours.
  • Severe infection: 1 to 4 g/day IV in divided doses every 6 hours or by continuous infusion.

Legionella Pneumonia

  • Although the dosage has not been established, clinical trials have used 1 to 4 g/day orally or IV in divided doses every 6 hours or by continuous infusion.

Pediatric Bacterial Endocarditis

  • 20 mg/kg (ethylsuccinate or stearate) orally two hours before the procedure, then one-half the amount six hours after initial dose.

Side Effects of Erythromycin 

The most common

More common

Rare

Drug interactions of Erythromycin 

Erythromycin may interact with following drugs,supplements & may change the efficacy of drugs

Pregnancy & Lactation

FDA pregnancy category B

Pregnancy

There is no evidence of hazard from erythromycin in human pregnancy. It has been in widespread use for a number of years without apparent ill consequence. Animal studies have shown no hazard.Erythromycin has been reported to cross the placental barrier in humans, but foetal plasma levels are generally low.

Lactation

This medication passes into breast milk. If you are a breast-feeding mother and are taking erythromycin, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

  • Azithromycin
  • Carbomycin
  • Cethromycin
  • Clarithromycin
  • Dirithromycin
  • Mitemcinal
  • Oleandomycin
  • Roxithromycin
  • Spiramycin
  • Telithromycin
  • Tylosin

References

 

Erythromycin; Uses, Dosage, Side Effects, Drug Interactions

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Start with a registered doctor or the nearest qualified health center.

What to tell the doctor

  • Write when the problem started and how it changed.
  • Bring old prescriptions, investigation reports, and current medicines.
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Questions to ask

  • What is the most likely cause of my symptoms?
  • Which danger signs mean I should go to hospital quickly?
  • Which tests are necessary now, and which can wait?
  • How should I take medicines safely and what side effects should I watch for?
  • When should I come for follow-up?

Tests to discuss

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  • Basic physical examination by a clinician
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Avoid these mistakes

  • Do not use antibiotics, steroid tablets/injections, or strong painkillers without proper medical advice.
  • Do not hide pregnancy, kidney disease, ulcer, allergy, or blood thinner use.
  • Do not delay emergency care when danger signs are present.

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Safe first steps

  • Avoid heavy lifting, sudden bending, and prolonged bed rest.
  • Use comfortable posture and gentle movement as tolerated.
  • Discuss physiotherapy, X-ray, or MRI only when clinically needed.

OTC medicine safety

  • For mild back pain, pain-relief medicine may be discussed with a doctor or pharmacist.
  • Avoid repeated painkiller use if you have kidney disease, stomach ulcer, uncontrolled blood pressure, or are taking blood thinners.

Avoid these mistakes

  • Do not start antibiotics without a proper medical decision.
  • Do not use steroid tablets or injections casually for quick relief.
  • Do not delay emergency care because of home remedies.

Get urgent help if

  • Back pain with leg weakness, numbness around private area, loss of urine/stool control, fever, cancer history, or major injury needs urgent care.
Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

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Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Orthopedic / spine specialist, physical medicine doctor, or qualified clinician
Tests to discuss with doctor
  • Neurological examination for leg power, sensation, reflexes, and straight leg raise
  • X-ray only if injury, deformity, long-lasting pain, or doctor suspects bone problem
  • MRI discussion if severe nerve symptoms, weakness, bladder/bowel problem, or persistent symptoms
Questions to ask
  • What is the most likely cause of my symptoms?
  • Which warning signs mean I should go to emergency care?
  • Which tests are really needed now?
  • Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?
  • Is physiotherapy, posture correction, or activity modification needed?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Safe pathway to proper treatment

Care roadmap for: Erythromycin; Uses, Dosage, Side Effects, Drug Interactions

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

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Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

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