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Erythromycin

Medication macrolide antibiotic antibiotic
Aka: Erythrocin
Brands seen in Singapore: Eryson, Erycyn, Ermycin, Retorin, Erysol
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Bacterial infections: chest, dental, sti, skin (NHS)
When to take
NHS: usually 2 to 4 times a day, doses spaced evenly
Take with
Water · NHS: the packet says if before or with food
Pros & cons
Pros
  • NHS: most adults and children can take it
  • SG: registered as tablets and as an oral suspension
  • NHS: courses usually run a few days or weeks
Cons
  • Nausea, vomiting, diarrhoea and bloating are common
  • SG label: not with domperidone, pimozide or cisapride
  • NHS: liver or gallbladder problems are a rare risk
Sources
  1. HSA — Listing of Registered Therapeutic Products (data.gov.sg open dataset, 5,511 rows, cached in full and filtered locally) · read 2026-08-27
    what it says
    “All 6 registered erythromycin products read 'Prescription Only' — SIN00578P ERYSON TABLETS 250 mg · SIN11952P ERYCYN-250 · SIN07545P ERMYCIN 250 · SIN11245P RETORIN · SIN00126P ERYSOL · SIN10446P ERYSON LOTION 2%”
  2. NHS Medicines A-Z — Erythromycin: what it is for · read 2026-08-27
    what it says
    “Erythromycin is mainly used to treat bacterial infections, including: chest infections, dental abscesses, sexually transmitted infections (STIs). It's also sometimes used to treat skin conditions such as acne and rosacea.”
  3. NHS Medicines A-Z — Erythromycin: how to take it · read 2026-08-27
    what it says
    “Most people need to take it 2 to 4 times a day for a few days or weeks … check the packet or leaflet to see if you need to take it before, or with, food”
  4. NHS Medicines A-Z — Side effects of erythromycin · read 2026-08-27
    what it says
    “Common side effects of erythromycin include: feeling sick (nausea) and being sick (vomiting), diarrhoea, not wanting to eat as much (loss of appetite), bloating and indigestion”
  5. NHS Medicines A-Z — Who can and cannot take erythromycin · read 2026-08-27
    what it says
    “Most adults and children can take erythromycin … it may not be suitable if: you've had an allergic reaction … you have liver or kidney problems, you have myasthenia gravis, you have a blood condition called porphyria”
  6. NHS Medicines A-Z — Taking erythromycin with other medicines, food and drink · read 2026-08-27
    what it says
    “domperidone … anticoagulants like warfarin or rivaroxaban … pimozide or amisulpride … statin medicines, such as simvastatin and lovastatin. Do not use the herbal supplement St John's wort when taking erythromycin.”
  7. National Drug Formulary (SG, MOH) — ERYCYN-250 TABLET 250 mg [SIN11952P]: dosage and contraindications · read 2026-08-27
    what it says
    “DOSAGE AND ADMINISTRATION: 250 mg 6 hrly; the dose may be doubled for severe infections … Syphilis: 1gm 6hrly for 10–15 days … contraindicated in patients taking astemizole, terfenadine, domperidone, cisapride or pimozide”
  8. US FDA label — erythromycin tablets (Zydus), DOSAGE AND ADMINISTRATION, via openFDA · read 2026-08-27
    what it says
    “The usual dosage of Erythromycin Tablets is one 250 mg tablet four times daily … Dosage may be increased up to 4 g per day according to the severity of the infection … should not exceed 4 g per day”
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Updated 2026-08-29. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.