Erythromycin: Uses, Dosage, Side Effects & Buying Tips
Erythromycin is a macrolide antibiotic you’ll often see for chest infections, skin infections, some STIs and acne. It kills bacteria by stopping their protein-making machinery. That makes it useful when penicillin isn’t an option or when a doctor prefers a macrolide.
It comes as tablets, capsules, liquid, topical gels and sometimes IV for severe infections. Which form you use depends on the infection type, how fast you need it to work, and tolerance for side effects.
How to take erythromycin and common doses
Adults commonly take 250–500 mg every 6–12 hours, depending on the infection. For kids, the dose is based on weight and given as a liquid or smaller tablets—your pediatrician will set the right amount. For acne, topical erythromycin gel or lotion is applied once or twice daily to the affected area.
Take oral erythromycin with food if it upsets your stomach, but some forms work better on an empty stomach—follow the label or your doctor’s instructions. Finish the full course even if you feel better, to avoid resistance.
Side effects, interactions and safety tips
The most common side effects are nausea, stomach cramps, vomiting and diarrhea. If you get severe diarrhea, dark urine, yellowing of the skin or persistent abdominal pain, contact your doctor—rare liver problems can occur.
Erythromycin can raise the levels of other drugs. Watch for interactions with certain statins, anti-arrhythmics, some antipsychotics and medications that lengthen the QT interval. Also avoid taking it with grapefruit juice—grapefruit can boost erythromycin levels and increase side effects.
Antacids can reduce absorption of some erythromycin forms. If you’re on other medicines, list them for your prescriber or pharmacist so they can check interactions. Pregnant or breastfeeding? Ask your healthcare provider before starting it.
Antibiotic resistance is a real issue. If a culture or test shows the bacteria are resistant, erythromycin may not work. Don’t use leftover antibiotics and don’t pressure clinicians for a prescription if it’s not needed.
To reduce stomach upset and lower the chance of antibiotic-related diarrhea, consider taking a probiotic during and for a week after the course—choose one with Lactobacillus or Saccharomyces boulardii and ask your pharmacist for a reliable brand.
Storage: keep tablets and liquids in a cool, dry place and check expiry dates. Liquids often need refrigeration after opening—read the label.
Buying & safety: erythromycin requires a prescription in most countries. If you’re considering an online pharmacy, use one that verifies prescriptions, shows contact information and has clear shipping and refund policies. Avoid suspiciously cheap offers, no-prescription sales, and sellers with poor reviews.
If you have questions about side effects, dosing for kids, or interactions with your current meds, call your doctor or pharmacist. Erythromycin can be very effective, but using it safely makes all the difference.