Ranceph is a prescription antibiotic containing cefalexin, a first-generation cephalosporin. It is used for bacterial infections of the skin, throat, ears, urinary tract and bone. It comes as 250 mg and 500 mg capsules and as paediatric suspensions. It has no effect on colds, flu or any other virus.
What is Ranceph?
Ranceph contains cefalexin (also spelled cephalexin) and is Schedule 4 — prescription-only:
| Product | Contains |
|---|---|
| Ranceph capsule | Cefalexin 250 mg |
| Ranceph capsule | Cefalexin 500 mg |
| Ranceph suspension | Cefalexin 125 mg/5 ml |
| Ranceph suspension | Cefalexin 250 mg/5 ml |
The suspensions are the paediatric forms, dosed by a child’s weight.
Cefalexin is a first-generation cephalosporin. Cephalosporins are closely related to penicillins — both are beta-lactam antibiotics, sharing the same core chemical structure and the same mechanism. They kill bacteria by blocking the enzymes that build the cell wall. Without an intact wall, the bacterium cannot withstand its own internal pressure and bursts.
“First-generation” describes what it covers, not how old or weak it is. Cephalosporins are grouped into generations by their spectrum:
- First generation (cefalexin): strong against Gram-positive bacteria — staphylococci and streptococci, the organisms behind most skin and throat infections. Limited Gram-negative cover.
- Later generations: progressively more Gram-negative cover, generally at the cost of some Gram-positive activity.
That focus is why cefalexin is a mainstay for skin infections. Most are caused by staph and strep, which it covers well, and using a narrow, targeted antibiotic is preferable to a broad one when the likely organism is known.
The relationship to penicillin matters clinically. Because the structures are related, someone allergic to penicillin may also react to a cephalosporin — though the overlap is smaller than was once believed. This must be a medical judgement, not an assumption.
What is Ranceph commonly used for?
A doctor may prescribe it for:
- Skin and soft-tissue infections — cellulitis, infected wounds, impetigo, boils and infected eczema. A common and well-suited use.
- Streptococcal throat infections, including tonsillitis, particularly where penicillin is unsuitable.
- Middle ear infections.
- Urinary tract infections.
- Bone and joint infections, in some cases.
- Respiratory infections caused by susceptible organisms.
- Dental infections, sometimes, alongside dental treatment.
- Preventing infection before certain procedures.
It has no effect on viruses. Colds, flu, most sore throats, most coughs and most bronchitis are viral. An antibiotic will not shorten them or prevent complications — and most sore throats do not need one.
How Ranceph fits into this medicine category
| Group | Examples | Typical role |
|---|---|---|
| Penicillins | Amoxicillin, flucloxacillin | Common first-line choices |
| Cephalosporins | Cefalexin (Ranceph), cefuroxime | Skin, throat, urinary infections |
| Penicillin + inhibitor | Amoxicillin/clavulanic acid | Where resistance is likely |
| Macrolides | Azithromycin | Chest infections, penicillin allergy |
| Fluoroquinolones | Ciprofloxacin | Urinary, gut and bone infections; reserved |
| Nitroimidazoles | Metronidazole | Anaerobic and some parasitic infections |
Which antibiotic is right depends on the likely organism, the site, local resistance patterns and your history. See the antibiotics and antimicrobials hub.
What to check before using Ranceph
Tell your doctor about any penicillin or antibiotic allergy before you start. This is the most important check, because of the structural relationship between cephalosporins and penicillins. Describe what actually happened — a mild rash years ago is a very different matter from swelling or difficulty breathing, and the distinction changes what can safely be prescribed.
Complete the full course, even once you feel better. Stopping early can allow the infection to return and encourages resistant bacteria.
Tell your doctor or pharmacist if you:
- Have had any reaction to a penicillin or cephalosporin, especially swelling, difficulty breathing or a severe rash.
- Have kidney disease, which usually means a lower dose or longer intervals.
- Have colitis or inflammatory bowel disease, or have had antibiotic-associated diarrhoea before.
- Have diabetes. Cefalexin can interfere with some older urine glucose tests.
- Are pregnant or breastfeeding.
- Take warfarin, metformin or probenecid.
- Use the combined oral contraceptive pill. Antibiotics do not generally reduce its effectiveness, but severe vomiting or diarrhoea can — ask a pharmacist.
Cefalexin can be taken with or without food, though food may reduce stomach upset. Take doses at evenly spaced intervals.
Shake suspensions well before each dose, use the measuring device supplied rather than a kitchen spoon, and check storage — most reconstituted suspensions must be refrigerated and discarded after a set number of days.
Possible cautions and when to ask a pharmacist or doctor
Common effects are diarrhoea, nausea, abdominal discomfort, and thrush (oral or vaginal). Cefalexin is generally well tolerated.
Stop and seek medical attention urgently if you develop:
- Swelling of the face, lips, tongue or throat, difficulty breathing, or a widespread hives-like rash — a serious allergic reaction. Call emergency services.
- Any rash, which should be assessed rather than ignored.
- Blistering or peeling skin, or sores in the mouth or eyes.
- Severe, watery or bloody diarrhoea, during or in the weeks after the course. This may indicate a C. difficile infection, and anti-diarrhoeal medicines such as loperamide should not be used in that situation.
- Yellowing of the eyes or skin, or dark urine.
- Fever, sore throat or mouth ulcers, which may indicate a blood problem.
- Unusual bruising or bleeding.
- Much less urine than usual.
- Seizures, which are rare and more likely with kidney impairment.
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 and a different antibiotic may be needed.
For a skin infection, watch the edge. If redness is spreading, the area is increasingly painful or swollen, red streaks appear, or you develop fever or feel generally unwell, seek medical attention promptly rather than waiting to finish the course.
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 are Ranceph capsules used for? Bacterial infections of the skin, throat, ears, urinary tract and bone. Ranceph contains cefalexin and is prescription-only.
What is Ranceph 250 used for? The lower capsule strength, used for the same infections. Your doctor chooses the strength based on the infection and your kidney function.
What is Ranceph 500 used for? The higher capsule strength, commonly used in adults for skin and other infections.
What is Ranceph suspension used for? The paediatric liquid form, dosed by a child’s weight, for the same range of infections.
Is Ranceph a penicillin? No, but it is closely related — a cephalosporin. Tell your doctor about any penicillin allergy, as reactions can overlap.
Can I take it if I am allergic to penicillin? Sometimes, but only your doctor can judge that. Describe exactly what happened during the previous reaction.
Will it help flu or a cold? No. Those are viral, and antibiotics have no effect on them.
Can I stop when I feel better? No. Finish the prescribed course unless your doctor tells you otherwise.