Co-amoxiclav (Augmentin): uses, side effects and cautions

The NHS describes co-amoxiclav as a penicillin-based antibiotic, and the name tells you it is built on amoxicillin with a second ingredient added.

The infections named by the NHS include ear and sinus infections, throat, airway and lung infections, skin infections and dental infections .

Tablets are swallowed whole with water; the liquid is measured with the syringe or spoon in the pack. Because it can unsettle the stomach, the NHS recommends taking each dose with a meal. Doses should be spaced evenly through the day and at least 4 hours apart.

Most people take it three times a day for a few days or weeks, as set by the prescriber. Finish the whole course even if you feel better.

• Missed dose: take it when you remember, then leave at least 4 hours before the next. Skip it if the next dose is nearly due. Do not double up.

• If you think you have taken too much, ask a pharmacist or NHS 111.

The NHS lists several reasons to avoid co-amoxiclav: an allergic reaction to it or to other antibiotics, previous liver problems or jaundice caused by an antibiotic, suspected or confirmed glandular fever, and kidney problems that need assessment.

The liver point is the distinctive one. A person who developed jaundice after co-amoxiclav or a related antibiotic should tell every prescriber, since a different antibiotic is the usual answer.

Common side effects are diarrhoea, feeling or being sick and thrush. Taking doses with meals helps with nausea, and thrush, which can show up as white patches in the mouth or irritation in the genital area, can be treated once a pharmacist or doctor has confirmed it.

The serious reactions below are rare, but they are the reason the leaflet is worth reading before the first dose. Some of them, such as liver effects, can appear after the course has finished, so keep the warning signs in mind for a while afterwards.

• Call 999 for anaphylaxis: swollen throat or tongue, rash, trouble breathing.

• Seek urgent advice for skin reactions with blisters or peeling.

• Seek advice quickly if you develop pale stools, dark urine or yellowing of the skin or eyes, which can mean a liver problem.

• Severe pain in the stomach that spreads to the back can signal acute pancreatitis and needs urgent assessment.

The NHS says you can usually take co-amoxiclav in pregnancy and that it is generally safe in breastfeeding. A baby should be watched for diarrhoea, oral thrush, rash, feeding changes or unusual sleepiness.

Allopurinol and probenecid (gout medicines), warfarin and methotrexate are named as medicines to review with the prescriber.

The NHS page lists no alcohol restriction, and driving is fine unless the medicine makes you dizzy. Check the leaflet for details.

If co-amoxiclav is unsuitable, the prescriber will choose a different antibiotic. You can report suspected side effects to the MHRA Yellow Card scheme.

Co-amoxiclav is prescription only. Tell whoever prescribes it about every other medicine you take, including anything bought over the counter, and keep the patient information leaflet from the pack, which lists the full set of warnings.