Dosage and strength
The amount of phenoxymethylpenicillin you need depends on your age and how bad the infection is, and whether you're taking it to treat or prevent an infection.
Phenoxymethylpenicillin comes as 250mg tablets and as a liquid.
There are 2 strengths of liquid available. The lower strength is 125mg/5ml and the higher strength is 250mg/5ml. Both strengths can also come as a sugar free liquid.
Adults and children 12 years old and over will usually take:
- 500mg 4 times a day for treating infections
- 500mg 2 times a day for preventing infections
The dose for children under 12 years old depends on their age and weight.
The usual dose for treating infections in younger children is:
- children aged 1 month to 11 months have 62.5mg, taken 4 times a day
- children aged 1 to 5 years have 125mg, taken 4 times a day
- children aged 6 to 11 years have 250mg, taken 4 times a day
The dose for preventing infections is usually taken twice a day. The strength depends on which infection is being prevented.
How to take it
Try to space the doses evenly throughout the day. If you take phenoxymethylpenicillin 4 times a day, this could be first thing in the morning, around midday, late afternoon and at bedtime.
If you're taking it twice a day, leave 12 hours between each dose. For example you could take it at 8am and 8pm.
It's best not to take phenoxymethylpenicillin at mealtimes because food can stop it from working well. Take it 30 minutes before a meal or at least 2 hours after you have eaten.
Swallow phenoxymethylpenicillin tablets whole. Do not chew or break them.
If you or your child are taking phenoxymethylpenicillin as a liquid, your pharmacist will make it up for you.
The medicine will come with a plastic syringe or spoon to help you measure out the right dose. If you do not have one, ask your pharmacist for one. Do not use a kitchen teaspoon as it will not measure the right amount.
How long to take it for
How long you take it for depends on the type of infection you have.
The usual course of phenoxymethylpenicillin lasts for 5 to 10 days.
If you're taking phenoxymethylpenicillin to prevent infection (for example, if you have sickle cell disease or have had chorea, rheumatic fever or your spleen removed), you may have to take it for the rest of your life.
Important
Carry on taking this medicine until you have completed the course, even if you feel better. If you stop your treatment early, the infection could come back.
If you forget to take it
If you forget to take a dose, take it as soon as you remember, unless it's nearly time for your next dose. In this case, just leave out the missed dose and take your next dose at the usual time.
Never take 2 doses at the same time. Never take an extra dose to make up for a forgotten one.
If you forget doses often, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.
If you take too much
Taking an extra dose of phenoxymethylpenicillin is unlikely to harm you or your child.
Taking more than 1 extra dose could make you feel sick and cause vomiting and diarrhoea. Rest and take it easy until these side effects get better. Speak to your pharmacist or doctor if you're worried.