Erythromycin: Patient Information for Australia
Basic Product Information
| International Non-Proprietary Name (INN) | Erythromycin |
| Australia Brand Names | Eryc, Erythrocin, E-mycin, Erythroped, Erythromycin Sandoz, Erythromycin APOTEX |
| ATC Code | J01FA01 |
| Available Forms & Strengths | Tablets/capsules: 250 mg, 400 mg, 500 mg Oral suspension: 125 mg/5 mL, 250 mg/5 mL Intravenous (IV) injection: 500 mg/vial |
| Manufacturers | Pfizer, Sandoz, Apotex, Beta Pharmaceuticals |
| Prescription Status (Australia) | Prescription Only (Schedule 4, PBS subsidised in some uses) |
Mechanism of Action
For patients: Erythromycin is an antibiotic. It works by stopping the growth of certain bacteria that cause infections. It does this by interfering with the ability of bacteria to make proteins needed for their survival.
For specialists: Erythromycin is a macrolide antibiotic that binds to the 50S subunit of bacterial ribosomes, inhibiting protein synthesis by blocking translocation. It is mainly bacteriostatic but may be bactericidal at higher concentrations or against highly-susceptible organisms.
Pharmacokinetics
- Absorption: Absorbed in the upper small intestine; bioavailability is variable (25–60%) due to acid lability.
- Distribution: Well-distributed throughout most tissues; poor cerebrospinal fluid penetration.
- Metabolism: Primarily metabolised by the liver (CYP3A4 enzyme); significant first-pass metabolism.
- Elimination: Mainly excreted in bile; a small amount via urine.
- Duration of Action: Dosing generally every 6 hours; effect duration approximately 6–12 hours depending on formulation.
Use in Everyday Life and Best Practices
Common Uses: Erythromycin is used to treat a wide range of bacterial infections, including:
- Respiratory tract infections (such as pneumonia, bronchitis, and pertussis)
- Skin and soft tissue infections (including acne in adolescents and adults)
- Ear, nose, and throat infections
- Prevention and treatment of certain sexually transmitted infections (such as chlamydia during pregnancy)
- Gastroparesis (off-label use, as a promotility agent)
Typical Doses: For adults, the usual range is 250–500 mg every 6–12 hours, depending on the infection and the form prescribed. For children, dosing is typically based on weight.
How to use: Take Erythromycin exactly as prescribed by your doctor. Swallow tablets or capsules whole with a glass of water. If you are using the oral suspension, measure the dose carefully using the provided device.
In the English context: Patients are encouraged to complete the full course of antibiotics even if they begin to feel better before finishing the medication, to prevent the development of antibiotic resistance.
Dosing in the Morning vs Evening
- Advantages of Morning Dosing: May improve adherence by fitting into morning routines; may reduce risk of forgetting doses before sleep.
- Advantages of Evening Dosing: Spacing doses evenly over 24 hours may be required for divided dosing.
- Tips: Try to take your doses at the same times each day. Setting alarms or reminders can help ensure regularity.
If prescribed more than once daily (e.g. every 6 hours), take at evenly spaced times, including morning and bedtime.
Taking with Food or on an Empty Stomach
Erythromycin can be taken with or without food. Taking it on an empty stomach (1 hour before or 2 hours after a meal) improves absorption, especially for the standard base form. However, some people experience stomach upset, in which case it is acceptable to take it with food to help with tolerability. In typical Australian diets, high dairy or fatty meals may delay absorption slightly but do not significantly affect efficacy.
Interaction Warnings
| Substance or Class | Effect | Recommendation |
|---|---|---|
| Certain Statins (simvastatin, atorvastatin, lovastatin) | Increased risk of muscle toxicity (myopathy/rhabdomyolysis) | Avoid combination; alternative statins (pravastatin, rosuvastatin) preferred |
| Warfarin | May increase bleeding risk | Monitor INR closely, adjust warfarin dose as needed |
| Theophylline | May increase theophylline blood levels | Monitor for toxicity, adjust dosage if required |
| Antacids (aluminium/magnesium compounds) | May delay absorption of erythromycin | Take antacids at least 2 hours apart from erythromycin |
| Alcohol | No direct dangerous interaction, but may worsen side effects (stomach upset) | Best to avoid excessive alcohol use during antibiotic treatment |
| Other antibiotics (clindamycin, chloramphenicol, lincomycin) | Possible antagonism | Use with caution and only if prescribed together |
| Food (high fat/heavy meals) | May delay absorption | Take on an empty stomach if possible, unless stomach upset occurs |
| St John’s Wort / Herbal Medicines | May affect erythromycin metabolism | Inform your doctor/pharmacist of all supplements and herbal products |
Indications
| Condition/Use | Officially Approved | Off-label |
|---|---|---|
| Respiratory tract infections | Yes | No |
| Skin and soft tissue infections | Yes | No |
| Pertussis (whooping cough) & prophylaxis | Yes | No |
| Acne vulgaris, moderate | Yes (oral and topical forms) | No |
| Chlamydia (in pregnancy) | Yes | No |
| Gastroparesis/motility disorders | No | Yes (as prokinetic agent, specialist use only) |
| Helicobacter pylori eradication | No | Yes (rarely used, not first-line in Australia) |
Dosing According to Clinical Indications
| Indication | Adults | Children | Elderly |
|---|---|---|---|
| Respiratory tract infections | 250–500 mg every 6 hours | 30–50 mg/kg/day divided every 6 hours | As per adult dosing; monitor for hepatic function |
| Skin/soft tissue infections | 250–500 mg every 6 hours | 30–50 mg/kg/day divided every 6 hours | As above |
| Pertussis | 500 mg every 6 hours for 7–14 days | 10 mg/kg every 6 hours for 7–14 days (max 2 g/day) | As per adult |
| Acne | 250–500 mg twice daily for 1–3 months | As directed by specialist | As above |
| Chlamydia (pregnancy) | 500 mg four times daily for 7 days | Not routinely given | As above |
| Gastroparesis (off-label) | 100–250 mg three or four times daily before meals | As directed by specialist | As above |
Safety Profile and Side Effects
| Frequency | Side Effect | Signs to Watch For | Action |
|---|---|---|---|
| Common (>1%) | Stomach upset, diarrhoea, abdominal pain, nausea, vomiting, loss of appetite | Feeling sick, loose stools | Usually mild; take with food if needed |
| Moderate | Rash, mild allergic reactions, headache, altered taste | Skin rash, itching | Inform your doctor if persistent |
| Rare (<1%) | Severe allergic reaction (anaphylaxis), jaundice or hepatitis, heart rhythm changes (QT prolongation), hearing changes (at very high doses or renal failure), Stevens-Johnson syndrome | Swelling, severe rash, yellowing eyes/skin, palpitations, fainting | Seek urgent medical attention |
| Other | Superinfection (thrush, C. difficile diarrhoea) | White patches, persistent diarrhoea | Contact your doctor if symptoms appear |
Guidelines for Proper Use (Pharmacist and Clinic Advice)
- Always finish the entire course of antibiotics, even if you feel better earlier.
- Take your medicine at the same times daily to maintain consistent antibiotic levels.
- If you miss a dose, take it as soon as you remember. Do not double up on doses.
- Store tablets/capsules below 25°C in the original packaging; liquid form may require refrigeration. Check Australian storage guidance on your package.
- Only use for your current infection; do not share with others.
- If you develop severe diarrhoea, skin rash, yellowing of eyes/skin, or difficulty breathing, seek urgent medical attention.
- Pharmacists can provide a medication summary and reminders on safe use. Consult your local GP or pharmacist with any concerns.
Alternative Treatment Options
- Clarithromycin, Azithromycin (other macrolides): Often preferred for better gastrointestinal tolerability, once-daily dosing (azithromycin), and similar spectrum. Both PBS-listed for select indications. Risk of interacting with certain medications is similar.
- Doxycycline (tetracyclines): Effective for respiratory and some sexually transmitted infections in non-pregnant adults; not suitable in pregnancy or for young children due to dental effects. PBS-listed, relatively inexpensive.
- Penicillins/Cephalosporins: Where bacterial resistance is not an issue, pencillins (amoxicillin, flucloxacillin) commonly used. Avoid in true penicillin allergy. PBS-listed.
- Clindamycin: Used for skin and bone infections, or when macrolide allergy exists. More risk of C. difficile diarrhoea.
- Pros/Cons: Erythromycin has the benefit of being safe in pregnancy (when needed) but more likely to cause stomach upset compared to newer macrolides.
Legal, Registration, and Reimbursement Status in Australia
- Legal Status: Prescription-only medicine (Schedule 4 under the Poisons Standard)
- ARTG Registration: Erythromycin and its marketed products registered on the Australian Register of Therapeutic Goods (ARTG)
- Reimbursement: PBS-subsidised for listed indications such as certain respiratory tract infections and pertussis. A Medicare Benefits Schedule (MBS) item applies for relevant diagnostic codes.
- Prescriber Restrictions: General practitioners, specialists, and nurse practitioners (with arrangement) can prescribe.
Latest Research and Clinical Guidance (2022–2025)
- Macrolides and Heart Risk: Recent guidance from NPS MedicineWise and the Therapeutic Guidelines (Antibiotic, 17th ed, 2024) highlights rare cardiac risks (QT prolongation, arrhythmia) with macrolide antibiotics, especially in those with existing heart conditions or on other QT-prolonging drugs.
- Efficacy in Whooping Cough: RANZCOG and RACGP endorse Erythromycin as the first-line treatment for pertussis contacts under 6 months or where macrolide alternative allergy exists. Still effective as prophylaxis.
- Use in Gastroparesis: Off-label erythromycin remains in use as a promotility agent but should be carefully monitored due to declining efficacy with long-term use.
- Antibiotic Stewardship: The Australian Commission on Safety and Quality in Health Care (ACSQHC) includes erythromycin in their national antibiotic stewardship guidelines, emphasising its appropriate, case-based use to avoid resistance.
- Citations: Recent reviews in the Medical Journal of Australia (MJA 2023), and official TGA advisories.
Availability and Delivery
| Pack Size (Tablets/Capsules) | Oral Suspension | Average Retail Price (AUD) | Delivery Time (Metropolitan) | Delivery Time (Regional/Remote) |
|---|---|---|---|---|
| 25, 100 tablets/caps | 100 mL, 200 mL bottles | $13–$30 (PBS patient co-payment usually applies, approx $7 for general, $5 for concession) | Next business day (Sydney, Melbourne, Brisbane) | 2–3 business days (Darwin, Perth, Hobart, regional NSW/VIC) |
Availability is generally good in all major cities and towns. IV formulations may be limited to hospital supply only. Speak to your pharmacist for up-to-date stock information.
Frequently Asked Questions (FAQ)
- Can I drink alcohol while taking erythromycin?
It is best to avoid excessive alcohol use with antibiotics, as alcohol can worsen stomach side effects. Occasional moderate alcohol (for example, a glass of wine with dinner) is unlikely to interact but may increase stomach upset. Always check with your doctor or pharmacist. - What should I do if I miss a dose?
If you miss a dose, take it as soon as possible unless it is almost time for your next dose. Do not double the next dose. - Can I use erythromycin if I am pregnant or breastfeeding?
Erythromycin is considered one of the safer antibiotics for use in pregnancy and breastfeeding, but it should only be used under direct medical supervision. Inform your doctor if you are pregnant, planning pregnancy, or breastfeeding. - How soon should I feel better?
For most infections, symptoms start improving within 2–3 days of starting antibiotics. However, some conditions (like severe or persistent infections) may require longer. If you do not feel better after several days, contact your GP. - Can erythromycin cause allergies?
Allergy is uncommon but can occur. Seek medical help immediately if you develop swelling, difficulty breathing, or a widespread rash.
