Penicillin Side Effects

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Answer the side-effect intent for penicillin without diagnosing; distinguish common from serious reactions and give safe next-step/reporting guidance.

What is penicillin?

Penicillin antibiotics covers several products registered in South Africa, not one. They work in a similar way, and their approved leaflets do not list identical side effects.

The medicines covered here, and the leaflet used for each:

• benzylpenicillin — BENZATHINE Benzylpenicillin 1.2 & 2.4 MU Ando, Ando Pharma (Pty) Ltd (Powder for Suspension for Injection)
• amoxicillin — Mymox 250 / 500, Unichem SA (Pty) Ltd (Capsules, hard.)
• phenoxymethylpenicillin — METPEN 125/250, Austell Laboratories (Pty) Ltd (Powder for oral solution)
• flucloxacillin — MACROPEN, Viatris South Africa (Pty) Ltd (Capsules and Macropen powder for suspension)

Common side effects of penicillin

Each medicine in this group has its own approved leaflet, and the effects below are the ones that leaflet lists. They are shown separately rather than combined, because the leaflets do not agree on what to list or how to word it.

Benzylpenicillin (BENZATHINE Benzylpenicillin 1.2 & 2.4 MU Ando)

• fungal infection (candidiasis)
• diarrhoea
• nausea
• inflammation of the lining of the mouth (stomatitis) and of the tongue (glossitis)
• being sick (vomiting)
• changes in certain test and investigation results performed by your doctor
• kidney inflammation (interstitial nephritis)
• inflammation of the blood vessels
• certain blood disorders (so called leukopenia, thrombocytopenia, agranulocytosis)
• prolongation of bleeding time, defective platelet function
• allergic reactions including hives, swelling, skin reactions, fever, painful joints, anaphylactic shock with collapse and asthma, skin bleeding (purpura) and gastrointestinal complaints (anaphylactoid reactions)
• sore mouth or tongue and black, hairy tongue

The leaflet lists 12 more. Read the full leaflet.

Amoxicillin (Mymox 250 / 500)

• Inflammation of the vagina, causing itching, burning, pain and discharge
• Abnormal taste, headache, dizziness
• Hot flushes
• Feeling tired
• Diarrhoea, nausea (feeling sick), vomiting (being sick), indigestion, stomach pain, black ‘hairy’ tongue
• Gastritis (pain, nausea, vomiting, vomiting blood, blood in the stool), inflammation of the mouth or tongue
• Anaemia (fatigue, loss of energy, pale skin, cramps in your legs, difficulty with concentration)
• Low number of cells involved with blood clotting; blood may take longer to clot than it normally would
• Convulsions (fits)
• Hyperactivity. Side effects with an unknown frequency:
• Thrush (a yeast infection of the vagina, mouth or skin folds)

Phenoxymethylpenicillin (METPEN 125/250)

• pins and needles or numbness
• nausea, vomiting
• infections or fever (may be caused by low white blood cells)
• anaemia (may cause lack of energy or tiredness) jaundice (yellowing of skin or whites of the eyes)
• kidney problems, which might cause blood in the urine or reduced amounts of urine Side effects with frequency unknown:
• problems with blood clotting (unusual bleeding or bruising)
• sore mouth
• sore throat
• black hairy tongue
• rash with blisters arranged in a circle with central crusting or like a string of pearls (linear IgA disease)
• Chest pain in the context of allergic reactions, which may be a symptom of allergy triggered heart disease (Kounis syndrome)

Flucloxacillin (MACROPEN)

• Swelling of the hands, feet, ankles, face, lips, mouth or throat, which may cause difficulty in swallowing or breathing
• Rash or itching
• Fainting
• Inflammation of the protective membrane surrounding the brain (aseptic meningitis)
• These are all very serious side effects. If you have them, you may have had a serious reaction to MACROPEN. You may need urgent medical attention or hospitalisation. Tell your doctor immediately or go to the casualty department at your nearest hospital if you notice any of the following:
• A widespread rash with blisters and peeling skin, particularly around the mouth, nose, eyes and genitals (Stevens-Johnson syndrome), and a more severe form, causing extensive peeling of the skin (more than 30 % of the body surface – toxic epidermal necrolysis)
• Widespread red skin rash with small pus-containing blisters (bullous exfoliative dermatitis)
• A red, scaly rash with bumps under the skin and blisters (exanthematous pustulosis)
• Flu-like symptoms with a rash, fever, swollen glands and abnormal blood test results (including increased white blood cells (eosinophilia) and liver enzymes) (drug reaction with eosinophilia and systemic symptoms (DRESS))
• Skin rash, which may blister, and looks like small targets (central dark spots surrounded by a paler area, with a dark ring around the edge – erythema multiforme)
• Chest pain which can be a sign of a potentially serious allergic reaction called Kounis syndrome
• Rash with blisters arranged in a circle with central crusting or like a string of pearls (linear IgA disease)

The leaflet lists 28 more. Read the full leaflet.

Serious side effects and warning signs

None of the leaflets reviewed set out a separate serious-effects list.

General warning signs that apply to any medicine

How long can side effects last?

How long a side effect lasts depends on the effect, the product, how long it has been used, and the person. Some effects ease within days as the body adjusts. Others continue for as long as the product is used. A few can persist after stopping, and some need review rather than waiting.

• Settling effects — mild effects that ease over the first days or weeks of use
• Ongoing effects — effects that continue while the product is being used and improve after stopping
• Persistent effects — effects that continue after stopping and need medical review
• Delayed effects — effects that appear after weeks or months rather than immediately

Which of these applies to a particular effect is a clinical question. If a side effect is not settling, is getting worse, or is affecting your daily life, that is worth a conversation with a pharmacist or doctor regardless of how long it has been going on.

Factors that may affect side effects

Cautions from each medicine’s approved leaflet.

Benzylpenicillin (BENZATHINE Benzylpenicillin 1.2 & 2.4 MU Ando)

Do not use it at all if:

• You have a hypersensitivity (allergic) reaction to penicillin or cephalosporins or any of the other ingredients of Benzathine Benzylpenicillin Ando (listed in section 6)
• Benzathine Benzylpenicillin Ando must not be given to babies, born to mothers who are allergic to penicillin during the neonatal period
• You have an inflammation of the inner layer of the heart (endocarditis), inflammation of the peritoneum, the thin tissue that lines the inner wall of the abdomen and covers most of the abdominal organs (peritonitis), an acute inflammation of the protective membranes covering the brain and spinal cord (meningitis). Benzathine Benzylpenicillin Ando should not be injected into any of your veins

Use with care, and tell your doctor, if:

• you have ever had an allergic reaction to other antibiotics like penicillin or other beta-lactam antibiotics
• you have kidney problems (your doctor may need to adapt the dose of this medicine)
• you have liver problems. If allergic symptoms occur (e.g., skin rash, itching, shortness of breath), tell a doctor immediately. Before treatment, a hypersensitivity test should be performed if possible. If an allergic reaction occurs, your doctor will stop your treatment and, if necessary, start appropriate therapy. As a possible cross-allergy should be considered in patients with hypersensitivity to cephalosporins, please tell your doctor if you have already had a previous allergic reaction to certain antibiotics (cephalosporins). If you have already been diagnosed with an allergy and/or allergic asthma or hay fever, you should tell your doctor. Severe immediate allergic reactions are possible even when the drug is administered for the first time. Based on general principles, in some cases you will remain under observation for at least half an hour after the medicine has been administered in case an acute allergic reaction should occur. If an allergy occurs, the doctor will take appropriate measures. Treatment with benzylpenicillin benzathine must be stopped immediately. When treating syphilis, a reaction to the bacterial toxins may occur, which lasts up to several days (Jarisch- Herxheimer reaction, Typical symptoms are sudden fever (sometimes with chills), pale skin; followed by skin redness, headache, painful muscles and joints or tiredness. To suppress or alleviate a Jarisch- Herxheimer reaction, your doctor will start appropriate therapy. In long-term treatment (more than a single dose), your doctor may arrange for checks on your blood count and liver and kidney function tests. Please make sure that you attend the check-ups prescribed by the doctor

Amoxicillin (Mymox 250 / 500)

Do not use it at all if:

• If you are hypersensitive (allergic) to amoxicillin trihydrate, penicillins, cephalosporins or any of the other ingredients of MYMOX (listed in section 6)
• If you have ever had an allergic reaction to any antibiotic, which can include a skin rash or swelling of the face or throat

Use with care, and tell your doctor, if:

• If you have epilepsy or meningeal disorders (inflammation of the membranes and fluid surrounding the brain and spinal cord), as MYMOX may increase the risk of convulsions (fits) when taken at high doses
• If you have kidney problems or are not urinating frequently
• If you have liver problems
• If you have been diagnosed with infectious mononucleosis, also called glandular fever (fever, sore throat, swollen glands and extreme tiredness)
• If you have been diagnosed with lymphatic leukaemia
• If you develop diarrhoea and stomach cramps, which may happen while you are taking MYMOX or a few months after you have stopped taking MYMOX

Phenoxymethylpenicillin (METPEN 125/250)

Do not use it at all if:

• if you are hypersensitive (allergic) to phenoxymethylpenicillin potassium, cephalosporin or any of the other ingredients of METPEN (listed in section 6)
• if you have ever had a skin rash or swelling of the face or neck or shortness of breath when taking any antibiotic

Use with care, and tell your doctor, if:

• If you suffer from any stomach problems e.g. vomiting
• If you suffer from any kidney problems
• If you suffer from allergies and/or asthma

Flucloxacillin (MACROPEN)

Do not use it at all if:

• If you or your child are hypersensitive (allergic) to amoxicillin, flucloxacillin, any other penicillins or any of the other ingredients of MACROPEN (listed in section 6)
• If you or your child have had a serious allergic reaction to any antibiotics. Some of the symptoms of an allergic reaction may include asthma, wheezing, shortness of breath, swelling of the face, lips or tongue which may cause difficulty in swallowing or breathing, skin rash, itching or hives
• If you or your child previously had jaundice (a medical condition with yellowing of the skin or whites of the eyes)
• Do not give MACROPEN to neonates

Use with care, and tell your doctor, if:

• If you or your child have a known allergy to penicillins as this could lead to an allergic reaction with collapse and sometimes death
• If you or your child have kidney problems
• If you or your child have glandular fever (fever, sore throat, swollen glands and extreme tiredness)
• If you or your child are not urinating regularly
• If you are breastfeeding or intend to breastfeed
• MACROPEN passes into breast milk and can be used only with caution during breastfeeding. However, breastfeeding must be stopped if gastrointestinal disorders (diarrhoea, candidiasis or skin rash) occur in the newborn

What to do if you experience side effects

If you think you are having a side effect, the response depends on how severe it is. Use the warning signs above first — if any of those apply, treat it as urgent.

If the symptom is severe or frightening

Get medical help immediately. Call 10177 for an ambulance, or 112 from a mobile phone, or go to the nearest emergency department. Take the product and its packaging with you if you can.

If the symptom is mild but bothering you

• Write down what the symptom is, when it started, and how it relates to when you take the product
• Check the leaflet that came with the product to see whether the symptom is listed
• Speak to your pharmacist — for many questions this is the fastest route to a useful answer
• Contact the prescriber if the symptom is affecting your daily life or is not settling

You can also report a suspected side effect in South Africa. Reporting does not replace getting medical advice, and you do not need to be certain the product was the cause.

When to seek urgent medical help

Some symptoms need medical attention straight away rather than an appointment in a few days. Do not wait to see whether they settle.

Get same-day medical advice if you have

• A high fever, or a rash together with feeling generally unwell
• Yellowing of the eyes or skin, or unusually dark urine
• Unusual bruising or bleeding that you cannot explain
• Severe or persistent vomiting or diarrhoea, especially if you cannot keep fluids down
• A sudden change in mood, or thoughts of harming yourself
• Any symptom that is rapidly getting worse

How to report a suspected side effect in South Africa

South Africa has an official system for reporting suspected side effects, run by the South African Health Products Regulatory Authority (SAHPRA). Reports from the public and from healthcare professionals are how safety signals get detected after a product is already in use.

Who can report

Anyone can report — you do not have to be a healthcare professional, and you do not need to prove that the product caused the problem. A suspicion is enough. Patients, caregivers and family members can all submit a report.

What to have ready

• The name of the product, its strength and form, and the batch number if you have it
• Why it was being used, and when it was started and stopped
• What the suspected reaction was, when it began, and how long it lasted
• Any other medicines, supplements or remedies being used at the same time
• Basic details about the person affected — age and sex are usually enough

How to report

SAHPRA accepts adverse reaction reports through its e-Services reporting system and through the Med Safety mobile app. Healthcare professionals can also report through the same routes. Current forms and access points are published on the SAHPRA site.

• SAHPRA Health Products Vigilance — the main vigilance and reporting hub
• SAHPRA e-Services — current adverse reaction reporting access

For a fuller walkthrough see how to report an adverse drug reaction.

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