Common questions about penicillin injections

Common questions about penicillin injections

Some answers to questions your child might have about their penicillin injections after they have had rheumatic fever.


Why does my child have to have injections for so long?

The injections protect your child from strep germs at the time in their life when they are in close contact with many people who could have a strep infection.

Why does my child need to have an injection every 28 days?

One injection gives your child enough penicillin to fight the strep germ for up to 28 days. Having an injection every 28 days means that there is enough penicillin in your child's body to help stop them from getting rheumatic fever again.

Is it true the injection can put weight on my child?

No - the injection won't cause your child to gain weight. Eating too much and not doing enough activity are the main causes of weight gain.

What if my child gets a sore throat?

Take your child to your doctor and get a throat swab. Your child will need an extra course of antibiotics to increase your protection.

Can my child have their injection early if we are going away?

Yes - it is better to be early than late. Talk to your nurse to arrange to have your child's injection early.

What happens if my child misses an injection?

It is very important that your child doesn't miss a penicillin injection. Missing one means that your child could get strep throat which can trigger rheumatic fever again.

If you forget an injection, ring your child's nurse to arrange to get your child's next injection as soon as possible.

Find out about an App to help get your bicillin on time every time

Check how to help make the penicillin injections more comfortable

See the page on rheumatic fever for information about causes, possible consequences, and treatment


The Paediatric Society of New Zealand is grateful to the Heart Foundation for providing the content for this page. The booklet 'Rheumatic fever and rheumatic heart disease' was revised in July 2019.

This page last reviewed 13 May 2020.

Call Healthline on 0800 611 116 any time of the day or night for free health advice when you need it