Varimax is azithromycin 250 mg, a macrolide antibiotic. It treats chest, throat, sinus, ear, skin and some sexually transmitted infections. Its distinguishing feature is that a short course — often three or five days — keeps working for days after the last capsule.
What is Varimax?
Varimax contains azithromycin 250 mg. The South African Medicine Price Registry lists it as a Schedule 4 capsule (prescription-only).
Azithromycin is a macrolide. It works by binding to the bacterial ribosome — the machinery bacteria use to build proteins — and stopping protein production. Without new proteins the bacteria cannot multiply, and the immune system clears them.
What makes azithromycin unusual is not how it kills bacteria but how it behaves in the body. It concentrates inside cells and in infected tissue, reaching levels far higher there than in the bloodstream, and it leaves very slowly — with a half-life of around 68 hours.
Two practical consequences follow:
Courses are short. Three days or five days is typical, where most antibiotics need seven to ten. A common pattern is a larger dose on day one followed by smaller daily doses.
It keeps working after you stop. Effective levels persist in tissue for several days after the final capsule. So finishing a three-day course and still feeling unwell on day four does not mean the antibiotic has stopped — it is still there.
That short course improves the odds people complete treatment, which is a real advantage. It also means the dosing looks different from other antibiotics, and it should be followed exactly rather than adjusted to seem more familiar.
Azithromycin is sold in South Africa under many names, including Azrotrin. Being given one instead of another is ordinary substitution.
What is Varimax commonly used for?
- Chest infections — bronchitis and community-acquired pneumonia, including the “atypical” organisms such as Mycoplasma, Chlamydophila and Legionella that penicillins do not cover.
- Sinusitis and middle ear infection, particularly in penicillin allergy.
- Throat and tonsil infection, as an alternative where penicillin cannot be used.
- Skin and soft tissue infections.
- Chlamydia and some other sexually transmitted infections, often as a single larger dose. Where an STI is treated, partners need treating too, or reinfection follows.
- Whooping cough (pertussis), both treatment and protecting close contacts.
- Travellers’ diarrhoea caused by certain bacteria.
- Preventing infection in people with weakened immunity, and in some chronic lung conditions where it is used long-term at low dose for its anti-inflammatory effect as much as its antibacterial one.
It does not treat colds, flu or most coughs and sore throats, which are viral. Azithromycin is prescribed for viral illness more often than almost any other antibiotic, and it does no good in that setting — only side effects and resistance.
Azithromycin resistance is a growing problem in South Africa and worldwide, which is one reason it is not a first choice for every infection.
How Varimax fits into this medicine category
| Group | Examples | Typical role |
|---|---|---|
| Macrolides | Azithromycin (Varimax, Azrotrin), clarithromycin, erythromycin | Atypical chest infections; penicillin allergy; some STIs |
| Aminopenicillins | Amoxicillin | Broad first-line cover |
| Penicillin + inhibitor | Co-amoxiclav | Where resistance defeats amoxicillin |
| Nitroimidazoles | Metronidazole | Anaerobic and dental infections, some parasites |
| Tetracyclines | Doxycycline | Atypical infections, acne, some STIs |
| Quinolones | Ciprofloxacin | Reserved for specific infections |
Azithromycin is often the answer to “what can this person have instead of penicillin?” See the antibiotics and antimicrobials hub.
What to check before using Varimax
Tell your doctor or pharmacist if you:
- Have a heart rhythm problem, particularly a long QT interval, or a family history of sudden cardiac death. This is the most important check with azithromycin — it can prolong the QT interval and, rarely, cause dangerous rhythm disturbances.
- Take other QT-prolonging medicines — some antipsychotics, antidepressants, antiarrhythmics, antifungals, and certain antimalarials. The risks add up.
- Have low potassium or magnesium, or are taking a diuretic that lowers them.
- Have liver disease. Azithromycin is cleared mainly by the liver.
- Have kidney disease or myasthenia gravis, which macrolides can worsen.
- Take warfarin, digoxin, ciclosporin, colchicine or ergot medicines for migraine.
- Take antacids containing aluminium or magnesium — separate them from azithromycin by about two hours.
- Have had a reaction to any macrolide before.
- Are pregnant or breastfeeding.
Practical points:
- Take it at the same time each day, with or without food. Food may reduce stomach upset.
- Follow the exact course, including a different dose on day one if that is what was prescribed.
- Complete it, even if you feel better after a day or two.
- Do not worry if symptoms take a few more days to settle after the last dose — the medicine is still in your tissues.
Possible cautions and when to ask a pharmacist or doctor
The most common effects are nausea, diarrhoea, abdominal pain and vomiting. Most are mild.
Get emergency help for:
- Palpitations, fainting, dizziness, or a very fast or irregular heartbeat — possible heart rhythm disturbance.
- Swelling of the face, lips or tongue, difficulty breathing, widespread hives, or a rash with blistering or peeling — serious allergic and skin reactions have been reported. Stop taking it.
- Severe, watery or bloody diarrhoea, especially with fever or cramping, during or in the weeks after the course — possible Clostridioides difficile infection.
- Yellowing of the skin or eyes, dark urine, pale stools, or severe abdominal pain — possible liver injury.
Contact your doctor if:
- The infection is not improving after three to four days, or is worsening.
- You develop breathlessness, chest pain, high fever or confusion.
- You are treating an STI and symptoms persist, or your partner has not been treated.
- Hearing changes or ringing in the ears develop — uncommon, usually with long-term use, and generally reversible.
- You develop thrush after the course.
Related medicine guides
Frequently asked questions
What is Varimax 250 mg used for? Bacterial infections of the chest, sinuses, ears, throat and skin, and some sexually transmitted infections including chlamydia. It contains azithromycin.
Why is the course only three or five days? Azithromycin concentrates in tissue and leaves the body very slowly, so a short course keeps working for several days after the last capsule.
I finished the course and still feel unwell — has it failed? Not necessarily. The medicine remains active in your tissues for days afterwards. But if you are not improving after three to four days, or are getting worse, see your doctor.
Is it a strong antibiotic? It is effective for the infections it covers, particularly atypical chest infections. Strength is less useful a question than whether it matches the organism.
Can I take it if I am allergic to penicillin? Usually yes — that is one of its main roles. Tell your prescriber about the allergy so they can confirm.
Will it treat a cold or flu? No. Those are viral and antibiotics have no effect on them.
Can I take it with an antacid? Separate them by about two hours. Aluminium and magnesium antacids reduce absorption.
Is it safe with heart problems? Tell your doctor. Azithromycin can affect heart rhythm, which matters if you have a QT abnormality or take other medicines that do the same.