Azithromycin 500 Biotech contains azithromycin 500 mg, a prescription antibiotic. It is used for chest and sinus infections, some sexually transmitted infections, and skin and throat infections. Biotech is the manufacturer. Its unusual feature is a very short course — often just three days.
What is Azithromycin 500 Biotech?
This product contains azithromycin 500 mg in tablet form and is Schedule 4 — prescription-only. “Biotech” is the manufacturer, Biotech Laboratories, not part of the medicine.
Azithromycin is widely available in South Africa under other names, including Azrotrin, Zithromax and various generics. Being dispensed one rather than another is ordinary generic substitution.
Azithromycin is a macrolide antibiotic. It binds to the bacterial ribosome — the machinery that assembles proteins — and blocks it, so the bacterium cannot make the proteins it needs to grow and divide. Human ribosomes are structured differently, which makes the effect selective.
What makes azithromycin distinctive is how it behaves in the body, and this explains almost everything unusual about how it is prescribed:
- It concentrates inside cells and in tissues, reaching levels in infected tissue far higher than in the blood. It is effectively carried to the site of infection by white blood cells.
- It has a very long half-life — it lingers in tissue for days after the last dose.
Together these mean a three-day course keeps working for around ten days. A short course that looks suspiciously brief is not an under-treatment; it is a property of the medicine. Finishing a three-day pack is completing the course, and this is a genuine and common source of confusion.
Macrolides are the standard alternative for people allergic to penicillin, since they are chemically unrelated — which is one of the main reasons azithromycin is prescribed.
It also covers “atypical” organisms — Mycoplasma, Chlamydia, Legionella — that penicillins miss entirely, making it useful in chest infections where these are likely.
What is Azithromycin 500 Biotech commonly used for?
A doctor may prescribe it for:
- Chest infections, including community-acquired pneumonia and infective exacerbations of COPD.
- Sinusitis, where symptoms are persistent or severe.
- Throat and tonsil infections, particularly in penicillin allergy.
- Middle ear infections.
- Chlamydia, as a single-dose or short-course treatment — a common use.
- Some other sexually transmitted infections, often alongside another antibiotic.
- Skin and soft-tissue infections.
- Whooping cough (pertussis), and preventing it in close contacts.
- Some gut infections, including travellers’ diarrhoea caused by susceptible bacteria.
- Trachoma, an eye infection, as a single dose.
It has no effect on viruses. Colds, flu, most sore throats, most coughs and most bronchitis are viral, and an antibiotic will not shorten them.
How Azithromycin 500 Biotech fits into this medicine category
| Group | Examples | Typical role |
|---|---|---|
| Macrolides | Azithromycin, clarithromycin, erythromycin | Chest infections, atypical organisms, penicillin allergy |
| Penicillins | Amoxicillin, flucloxacillin | Common first-line choices |
| Penicillin + inhibitor | Co-amoxiclav | Where resistance is likely |
| Cephalosporins | Cefalexin | Skin, throat, urinary infections |
| Tetracyclines | Doxycycline | Chest, skin, STIs, tick bite fever |
| Nitroimidazoles | Metronidazole | Anaerobic and some parasitic infections |
See the antibiotics and antimicrobials hub.
What to check before using Azithromycin 500 Biotech
Complete the course you were given, however short it looks. A three-day pack is a full course.
Take it at the same time each day. It can generally be taken with or without food, though food may reduce stomach upset.
Separate it from antacids containing aluminium or magnesium by at least two hours, as they reduce absorption.
Tell your doctor or pharmacist if you:
- Have any heart condition, particularly a rhythm disorder or prolonged QT interval, a slow heart rate, or heart failure. Azithromycin can affect heart rhythm, and this is its most important caution.
- Have low potassium or magnesium.
- Take other medicines affecting heart rhythm — some antipsychotics, antidepressants, antifungals, antimalarials and antiarrhythmics.
- Have liver disease. Azithromycin is cleared mainly by the liver.
- Have kidney disease.
- Have myasthenia gravis, which macrolides can worsen.
- Have had a reaction to any macrolide antibiotic before.
- Take warfarin, digoxin, ciclosporin, colchicine, or ergot medicines for migraine.
- Take statins, where muscle side effects can increase.
- Take antacids.
- Are pregnant or breastfeeding.
- Are being treated for a sexually transmitted infection, so partners can be tested and treated.
Possible cautions and when to ask a pharmacist or doctor
Common effects are nausea, diarrhoea, abdominal pain, vomiting and headache. Azithromycin is generally better tolerated than older macrolides such as erythromycin.
Stop and seek medical attention urgently if you develop:
- Palpitations, fainting, dizziness, or an irregular heartbeat — given the heart rhythm effect.
- Swelling of the face, lips, tongue or throat, difficulty breathing, or a widespread hives-like rash — a serious allergic reaction. Call emergency services.
- A rash, blistering or peeling skin, or sores in the mouth or eyes. Serious skin reactions are rare but recognised.
- Severe, watery or bloody diarrhoea, during or in the weeks after the course — possible C. difficile infection, where anti-diarrhoeal medicines should not be used.
- Yellowing of the eyes or skin, dark urine or pale stools — possible liver problems.
- Muscle weakness, particularly if you have myasthenia gravis.
- Hearing loss, ringing in the ears or dizziness, which have been reported with prolonged or high-dose use and usually reverse on stopping.
Contact your doctor if you are no better after two to three days of treatment, or if symptoms worsen at any point — the organism may not be susceptible.
If you were treated for a sexually transmitted infection, follow the advice given about avoiding sex until treatment is complete, and about partner testing. Reinfection is common when partners are not treated, and untreated chlamydia can cause lasting damage to fertility.
Never use antibiotics left over from a previous illness or prescribed for someone else.
Related medicine guides
- Browse Antibiotics, Antifungals & Antimicrobials guides
- Read: Azrotrin used for
- Read: Metronidazole used for
Frequently asked questions
What is Azithromycin 500 Biotech used for? Bacterial infections including chest and sinus infections, throat infections, chlamydia and other STIs, and skin infections. Each tablet contains azithromycin 500 mg.
What does “Biotech” mean on the pack? It is the manufacturer, Biotech Laboratories. The medicine is ordinary azithromycin 500 mg.
Why is the course only three days? Azithromycin concentrates in tissue and lingers for days after the last dose, so a three-day course keeps working for about ten. Finishing the pack is completing the course.
Will it help flu or a cold? No. Those are viral, and antibiotics have no effect on them.
Can I take it if I am allergic to penicillin? Macrolides are chemically unrelated to penicillins and are the usual alternative. Tell your doctor about any antibiotic allergy.
Can I take it with antacids? Separate them by at least two hours, as antacids reduce absorption.
Does it affect the heart? It can affect heart rhythm, which is its most important caution. Tell your doctor about any heart condition or medicines affecting rhythm.
Does my partner need treatment? For a sexually transmitted infection, yes — partners need testing and treatment, or reinfection is likely.