TL;DR:
- Co‑Amoxiclav is a combo antibiotic of amoxicillin + clavulanic acid, used for many bacterial infections.
- Typical adult dose: 625mg (500mg amoxicillin + 125mg clavulanic acid) three times daily for 7‑10days.
- Take it with food to reduce stomach upset; finish the whole course even if you feel better.
- Common side effects: nausea, diarrhoea, skin rash; severe reactions are rare but need immediate medical help.
- Ask your doctor about allergies, liver disease, or pregnancy before starting.
What Is Co‑Amoxiclav and How It Works?
Co‑Amoxiclav is the brand‑name or generic term for a fixed‑dose combination of two active ingredients: amoxicillin, a penicillin‑type antibiotic, and clavulanic acid, a beta‑lactamase inhibitor. Amoxicillin attacks the bacterial cell wall, preventing it from building a sturdy structure and ultimately causing the cell to burst. Some bacteria produce an enzyme called beta‑lactamase that destroys amoxicillin before it can work. That’s where clavulanic acid steps in - it binds to the enzyme and neutralises it, allowing amoxicillin to do its job.
This partnership expands the range of bacteria the drug can beat, making Co‑Amoxiclav a go‑to for infections that might be resistant to plain amoxicillin. In Australia, you’ll see it prescribed for ear infections, sinusitis, pneumonia, skin‑soft tissue infections, urinary tract infections, and dental abscesses, among others.
Because it hits a broad spectrum of both gram‑positive and gram‑negative bacteria, doctors often use it when they suspect a mixed infection or when culture results aren’t yet available. The trade‑off is a slightly higher chance of side effects compared with a single‑agent antibiotic, which is why it’s reserved for cases where the added coverage is genuinely needed.
When and How to Take Co‑Amoxiclav
Getting the dosing right is crucial for two reasons: you want the infection cleared quickly, and you want to minimise the chance of resistance developing.
Below is a quick‑reference table that covers the most common prescribing scenarios in Australia for adults and children over 12kg. Doses are expressed in the standard fixed‑dose tablets (e.g., 250mg/125mg, 500mg/125mg, 625mg/125mg).
| Infection Type | Typical Adult Dose | Typical Paediatric Dose (kg) | Duration |
|---|---|---|---|
| Acute otitis media | 500mg/125mg q8h | 25mg/kg amoxicillin + 5mg/kg clavulanic acid q8h | 5‑7days |
| Sinusitis (moderate‑severe) | 625mg/125mg q8h | 30mg/kg amoxicillin + 6mg/kg clavulanic acid q8h | 7‑10days |
| Pneumonia (community‑acquired) | 500mg/125mg q8h | 40mg/kg amoxicillin + 8mg/kg clavulanic acid q8h | 7‑10days |
| Skin & soft‑tissue infection | 625mg/125mg q8h | 35mg/kg amoxicillin + 7mg/kg clavulanic acid q8h | 7‑14days |
| Uncomplicated UTI (female) | 500mg/125mg q8h | Not routinely used in children | 5‑7days |
Key points to remember when you take the medication:
- Take with food or a full glass of milk. This helps reduce nausea and protects the stomach lining.
- Swallow tablets whole; crushing or chewing can release the drug too quickly, increasing side‑effects.
- If you miss a dose, take it as soon as you remember-unless it’s almost time for the next one. Don’t double up.
- Finish the entire prescribed course, even if symptoms improve after a couple of days. Stopping early encourages resistant bugs.
- Store tablets at room temperature, away from moisture and direct sunlight.
For children under 12kg, doctors usually pick a child‑specific formulation (e.g., paediatric oral suspension) rather than fixed‑dose tablets. Always follow the exact weight‑based instructions on the label.
If you’re on a prolonged regimen (more than two weeks), your doctor may order liver function tests periodically because clavulanic acid can strain the liver in rare cases.
Safety, Side Effects & Frequently Asked Questions
Like any medication, Co‑Amoxiclav isn’t risk‑free. Understanding what to watch for can keep you safe.
Common side effects (1‑10% of users)
- Nausea, vomiting, or mild stomach upset.
- Diarrhoea - often watery, sometimes with abdominal cramps.
- Skin rash or mild itching.
- Headache.
Most of these settle on their own within a few days. Taking the drug with food and staying hydrated usually eases gastrointestinal upset.
Less common but serious reactions
- Severe skin reactions (Stevens‑Johnson syndrome, toxic epidermal necrolysis). Look for blistering, widespread rash, or peeling skin.
- Signs of anaphylaxis: swelling of lips or throat, difficulty breathing, rapid heartbeat. This requires emergency care.
- Hepatotoxicity: yellowing of the eyes or skin, dark urine, persistent fatigue. Report these right away.
Who should avoid Co‑Amoxiclav?
- Anyone with a known allergy to penicillins, amoxicillin or clavulanic acid.
- Patients with a history of severe liver disease (e.g., cirrhosis) should discuss risks with their GP.
- Pregnant or breastfeeding women need a doctor’s approval; although the drug is classified as Category B2 in Australia (generally safe), individual circumstances differ.
Drug interactions you need to know
- Warfarin: Co‑Amoxiclav can increase INR values, raising bleeding risk. Monitor blood work closely.
- Allopurinol: may heighten rash risk.
- Oral contraceptives: antibiotics can slightly lower effectiveness. Use a backup method during treatment.
FAQ
- Can I take Co‑Amoxiclav for a viral infection? No. It only works against bacteria. Using it for a cold or flu won’t help and can promote resistance.
- What should I do if I develop diarrhoea? Stay hydrated and consider a probiotic. If stools become watery, contain blood, or persist beyond five days, call your doctor.
- Is it okay to drink alcohol while on this antibiotic? Moderate alcohol isn’t a direct contraindication, but both can upset the stomach. If you’re already feeling nauseous, skip the nightcap.
- Can I switch to a single‑agent antibiotic mid‑course? Only under medical advice. The doctor may de‑escalate based on lab results, but you shouldn’t decide on your own.
- What if I forget to take a dose before bedtime? Take it as soon as you remember, unless it’s close to the next scheduled dose; then skip the missed one and continue as normal.
Checklist before you start
- Confirm you’re not allergic to penicillin.
- Inform your GP about any liver issues or current medications.
- Ask if a short‑course (5‑7days) is appropriate for your infection.
- Plan to take the tablets with meals for the whole treatment period.
- Keep a log of any side effects and notify your doctor if they worsen.
By understanding what Co‑Amoxiclav does, how to use it correctly, and what signs to watch for, you can get the most benefit while keeping risks low. If anything feels off, don’t hesitate to get medical advice - antibiotics work best when you and your doctor stay on the same page.
