Phenoxymethylpenicillin

What is phenoxymethylpenicillin?

Phenoxymethylpenicillin is a type of prescription-only penicillin antibiotic used to treat and prevent bacterial infections[1]. 

What is phenoxymethylpenicillin used to treat?

Phenoxymethylpenicillin is commonly prescribed for[1][2]: 

• Throat infections (e.g., streptococcal pharyngitis, tonsillitis) 

• Chest infections 

• Ear infections 

• Skin infections (e.g., cellulitis) 

• Dental abscesses 

• Scarlet fever 

• Prevention of rheumatic fever  

• Prevention of infections in people with sickle cell disease or those without a spleen  

How does phenoxymethylpenicillin work?

Phenoxymethylpenicllin is an antibiotic that belongs to the penicillin family. It works by breaking down the bacteria’s protective cell wall, which helps your body fight off the infection and destroy the bacteria[1].  

Who can take phenoxymethylpenicillin?

Most adults and children can take phenoxymethylpenicillin, including during pregnancy and breastfeeding[1].  

Please tell your doctor or pharmacist about any conditions you may have before starting phenoxymethylpenicillin, and always follow the instructions in the Patient Information Leaflet[3]. 

Who may not be able to take phenoxymethylpenicillin?

Phenoxymethylpenicillin may not be suitable for everyone, and so to make sure it is safe for you, tell your doctor or pharmacist if you[3]: 

• Are allergic to penicillin 

• Have a history of asthma, eczema, or hay fever as there is a chance these may increase your risk of a reaction 

• Have kidney problems 

• Have any other known allergies 

How do you take phenoxymethylpenicillin?

Phenoxymethylpenicillin is available as tablets or liquid[1]. 

• Take it on an empty stomach, either one hour before food or two hours after 

• Try to space doses evenly throughout the day to keep a consistent level in your body. 

If you’re taking tablets: 

• Swallow them whole with water 

• Do not chew or break the tablets 

If you’re taking the liquid: 

• Use the syringe or measuring spoon provided to take the correct dose 

• Do not use a kitchen teaspoon, as this can lead to the wrong amount 

• If you don’t have a proper measuring device, ask your pharmacist for one. 

• Check the storage instructions as this may need to be kept in the fridge 

What is the typical dosage of phenoxymethylpenicillin?

The dose of phenoxymethylpenicillin depends on the condition being treated, age, weight if for a child, and how bad the infection is[1]: 

• Adults and children over 12 years: The typical dose for an active infection is 250mg to 500mg four times each day.  

• Children: Dose adjusted by weight and age 

• To prevent infections: Typically, 250mg twice daily.  

Always follow your doctor’s or pharmacist’s instructions and the instructions in the Patient Information Leaflet[3]. 

Can you stop taking phenoxymethylpenicillin?

No, you should not stop taking phenoxymethylpenicillin even if you feel better, you should always complete the full course. Stopping early can lead to the infection returning and bacteria becoming resistant[1]. 

What do you do if you take too much phenoxymethylpenicillin?

Taking an extra dose of Phenoxymethylpenicillin is unlikely to harm you. If you take more than 1 extra dose, it could cause nausea, vomiting, and diarrhoea. Speak to your pharmacist or doctor if you are worried[1]. 

What if you forget a dose of phenoxymethylpenicillin?

If you miss a dose, take it as soon as you remember. If it's almost time for your next dose, skip the missed dose and continue with your regular schedule. Never take 2 doses at the same time[1].  

It is important to try and remember every dose as taking the medication inconsistently could result in the infection getting worse. 

What are the side effects of phenoxymethylpenicillin?

The most common side effects are include[1][3]: 

• Nausea 

• Diarrhoea 

• A non-allergic penicillin rash  

Rare but serious side effects (seek immediate help)[1][3]: 

• Severe allergic reactions (swelling, difficulty breathing, rash). Call 999 or go to A&E 

• Severe watery and bloody diarrhoea, stomach pain and high temperature. Call 111 immediately or go to A&E if you are unwell 

A rash is a common side effect of penicillin, especially in children and doesn’t always mean you’re allergic. This type of rash is usually: 

• Mild, flat or slightly raised, and red 

• Appears a few days after starting treatment. Sometimes this can be up to 10 days later, which can be surprising if you have already finished the course 

• Most often seen on the trunk, back or limbs 

• Not itchy and doesn’t come with other symptoms 

This kind of rash is not dangerous and usually goes away on its own without the need for treatment. 

Medical advice should be sought if the rash: 

• Is widespread, itchy, or blistering 

• Accompanied with other symptoms such as difficulty breathing, swelling, or dizziness as this could be a sign of a true allergic reaction. This needs urgent care 

If you experience any side effects, including those not listed, you are encouraged to report them via the Yellow Card Scheme or contact your doctor, pharmacist, or nurse. This information is intended as a summary for general awareness and does not replace professional medical advice. 

The information provided in the side effects section is not a comprehensive list of all possible side effects associated with this medication. For a complete list of side effects, please refer to the Patient Information Leaflet (PIL) provided with your medication or consult your healthcare professional[3].  

Medicines you can’t take with phenoxymethylpenicillin

Some medications can affect how phenoxymethylpenicillin works or increase the risk of side effects. It’s important to let your doctor or pharmacist know about all medications, supplements, or herbal remedies you’re taking before starting this antibiotic[1][3]: 

• Methotrexate 

• Other antibiotics (e.g., tetracyclines may reduce effectiveness) 

• Warfarin 

Always inform your doctor or pharmacist about all medications and supplements you take before you start a new medicine, and follow the instructions in the Patient Information Leaflet[3]. 

Frequently asked questions about phenoxymethylpenicillin

Can I drink alcohol while taking phenoxymethylpenicillin? 

Yes, you can drink alcohol while taking phenoxymethylpenicillin however if you are already unwell, alcohol can increase the risk of dehydration. If you do choose to drink, always do so in moderation[1]. 

Is phenoxymethylpenicillin safe during pregnancy? 

Yes, phenoxymethylpenicillin is considered safe during pregnancy but always consult your doctor or pharmacist before taking it[1]. 

Is phenoxymethylpenicillin safe during breastfeeding? 

Yes, there is trace amounts in breast milk but it is safe to use. 

Can I drive while taking phenoxymethylpenicillin? 

Yes, you can, unless you feel dizzy or unwell[1]. 

Does phenoxymethylpenicillin affect birth control? 

Phenoxymethylpenicillin does not affect the contraceptive pill directly. However, if you experience vomiting or diarrhoea for more than 24 hours, whether caused by the medicine or the infection itself, the pill may not protect you from pregnancy. You should check the information leaflet that came with your contraceptive pill for guidance on what to do and when to use extra contraception[1]. 

Will phenoxymethylpenicillin give me thrush? 

Some people may get thrush after taking phenoxymethylpenicillin. This is because antibiotics kill the harmless bacteria as well as the bad bacteria allowing opportunistic yeast infections to establish. Talk to your doctor or pharmacist for advice on treatments[1]. 

For the official NHS guide to phenoxymethylpenicillin, visit their website.