Erythromycin: Uses, Dosage, Side Effects & Precautions

Erythromycin is a macrolide antibiotic used to treat a variety of bacterial infections, including respiratory tract infections, skin infections, and certain sexually transmitted infections. It works by stopping bacteria from producing the proteins they need to grow and survive.

At a Glance

When to Use Erythromycin

• Respiratory Infections: Erythromycin may be used for certain bacterial respiratory tract infections, such as some cases of pneumonia, bronchitis, or sinusitis, when a doctor determines it is appropriate based on the suspected organism, the clinical situation, and local resistance patterns. Many cases of bronchitis and sinusitis are viral and do not need antibiotics.
• Skin Infections: Erythromycin may be an option for selected bacterial skin infections, such as certain cases of cellulitis or impetigo, or for specific dermatological conditions like acne, but only when prescribed as appropriate by a doctor. It is not automatically the first-choice treatment for these conditions.
• Certain STIs: Chlamydia, in specific situations such as penicillin allergy or where preferred first-line antibiotics cannot be used, as directed by a doctor. Erythromycin is no longer recommended by current guidance as a treatment for chlamydial infection during pregnancy; a doctor will select a more appropriate option in that situation.

Erythromycin is not a recommended treatment for gonorrhea, due to widespread antibiotic resistance in the bacteria that cause it. Gonorrhea is treated with other antibiotics chosen by a doctor based on current resistance patterns.

Take erythromycin for the duration prescribed by your doctor. Do not skip doses or stop treatment early unless your doctor advises you to do so. Never use leftover or someone else’s antibiotics.

How Erythromycin Works

Erythromycin binds to bacterial ribosomes, blocking the production of proteins that bacteria need to grow and survive. By stopping this protein production, it helps the body clear the infection.

Dosage

Erythromycin dosing depends on the type and severity of infection, age, kidney and liver function, and the specific product being used. Only a doctor can determine the correct dose for a given patient — the figures below are general reference information, not a self-treatment guide.

• Adults: Oral doses are typically divided across the day, commonly ranging from 250 mg to 500 mg per dose, depending on the infection. A doctor sets both the dose and the maximum daily amount for a given case.
• Children: Pediatric oral dosing is weight-based and calculated by a doctor according to the child’s weight, age, and the infection being treated.
• Intravenous erythromycin is given only in a hospital or clinical setting, under direct medical supervision = it is not used at home.

Do not start, stop, or change the dose without medical guidance.

Common Side Effects

• Nausea
• Vomiting
• Stomach upset, cramping, or diarrhea

Serious side effects

• Heart rhythm changes (QT prolongation): Erythromycin can affect the heart’s electrical activity and, in rare cases, lead to a serious irregular heartbeat. The risk is higher in older adults, people with existing heart conditions, low potassium or magnesium levels, or those taking other medicines that affect heart rhythm.
• Liver problems: Erythromycin has been linked to liver injury, including a reversible form of liver inflammation with jaundice. Seek medical attention for yellowing of the skin or eyes, dark urine, or persistent abdominal pain.
• Infants under 2 weeks old: Erythromycin use in early infancy has been associated with an increased risk of infantile hypertrophic pyloric stenosis, a condition that causes forceful vomiting and requires prompt medical evaluation. Parents should contact a doctor if a treated infant develops persistent vomiting or feeding difficulty.

Contraindications

Do not use erythromycin if you:

• Are allergic to erythromycin or other macrolide antibiotics
• Are taking pimozide, astemizole, cisapride, or terfenadine
• Are taking simvastatin or lovastatin (statins metabolized the same way as erythromycin), due to an increased risk of serious muscle injury
• Are taking ergotamine or dihydroergotamine, due to the risk of a serious interaction (ergot toxicity, including reduced blood flow to the extremities)

Precautions

Talk to your doctor before using erythromycin if you have:

• Liver disease
• A heart rhythm condition, or are taking other medicines known to affect heart rhythm
• Myasthenia gravis, as macrolides may worsen muscle weakness
• Low potassium or magnesium levels

Erythromycin should be used cautiously, and only when clearly needed, in infants younger than 2 weeks old, with close monitoring for feeding problems or vomiting.

Drug Interactions

Erythromycin inhibits an enzyme (CYP3A4) involved in breaking down many other medicines, which can raise their levels in the body.

• Statins (simvastatin, lovastatin): Combined use is contraindicated due to a higher risk of serious muscle damage.
• Ergotamine and dihydroergotamine: Must not be combined with erythromycin due to the risk of serious ergot toxicity.
• Certain calcium-channel blockers (such as verapamil or diltiazem): Erythromycin can increase their levels or effects, which may contribute to low blood pressure or other adverse effects.
• Other QT-prolonging medicines (certain heart, antipsychotic, or antifungal drugs): may add to the risk of heart rhythm problems.
• Warfarin: erythromycin may increase its blood-thinning effect.
• Theophylline, digoxin, colchicine, phenytoin, and valproate: erythromycin can raise blood levels of these drugs, increasing the risk of side effects.

Tell your doctor about all prescription medicines, over-the-counter medicines, and supplements you take. This list is not complete.

Pregnancy and Breastfeeding

Pregnancy

Erythromycin may be used in pregnancy in specific situations when a doctor determines it is needed, but the estolate salt form of erythromycin should be avoided in pregnancy because of a higher risk of liver problems in the mother. It is no longer the recommended choice for treating chlamydial infection in pregnancy under current guidance. Some studies have suggested a possible small increase in certain heart-related birth differences with early pregnancy exposure to erythromycin-containing products; the evidence is not conclusive. Use in pregnancy should be guided by a doctor.

Breastfeeding

Erythromycin passes into breast milk in small amounts and is generally considered compatible with breastfeeding, but you should still discuss use with your doctor, particularly when breastfeeding a very young infant.

Approximate Price in India

• Erythrocin 250 mg Tablet (strip of 10): approximately ₹40–₹65
• Erythrocin 500 mg Tablet (strip of 10): approximately ₹75–₹125

Prices may vary by brand, strength, formulation, pack size, pharmacy, location, and available discounts.

How HealthPil Can Help

Erythromycin should be started, adjusted, or stopped only under the guidance of a qualified healthcare professional. If you have questions about this medicine, its side effects, or your treatment plan, you can consult a doctor through HealthPil.