Answer the side-effect intent for flucloxacillin without diagnosing; distinguish common from serious reactions and give safe next-step/reporting guidance.
Source
Clinical statements on this page are taken from the SAHPRA-approved patient information leaflet (approved 11/09/2023) and professional information (approved 11/09/2023) for this product: patient information leaflet, professional information. Retrieved 2026-09-03. Where this page and the approved leaflet differ, the leaflet is correct.
What is flucloxacillin?
Which leaflet this comes from
There is no approved leaflet for Flucloxacillin in SAHPRA’s public repository. The information below is from the approved leaflet for Sandoz Flucloxacillin, another South African product containing Flucloxacillin. Products with the same active ingredient can still differ in strength, formulation and approved uses, so check the leaflet in your own pack.
Flucloxacillin contains the active ingredient Flucloxacillin.
- Active ingredient — Flucloxacillin
- Registration number — T/20.1.2/33
- Registration holder — Sandoz SA (Pty) Ltd
It is approved for:
- Infections caused by penicillinase producing staphylococci
Common side effects of flucloxacillin
Not everyone gets side effects. The effects below are those listed in the South African approved leaflet, grouped using the leaflet’s own frequency wording.
About these frequency terms
This leaflet groups effects as “Frequent” and “Less frequent” rather than the very common/common/uncommon scale used in some other markets.
Frequent side effects
- Feeling sick (nausea)
- Diarrhoea
- Minor gastrointestinal disturbances Less-frequent side effects:
- Changes in numbers of different blood cells (causing unexplained bleeding, bruising or skin discolouration, and seen in blood tests)
- Rapid swelling (angioneurotic oedema)
- Allergic skin reactions that can cause swelling, itching and a rash (urticaria)
- Purpura (brownish-red spots on the skin)
- Arthralgia (pain in a joint) and myalgia (pain in the muscles)
- Interstitial nephritis (inflammation of the kidneys)
- Fever
- Very rare cases of increased acid production in the body (high anion gap metabolic acidosis), causing the blood to become more acidic (confirmed with a test), which may occur when SANDOZ FLUCLOXACILLIN is used together with paracetamol, generally in the presence of risk factors
Serious side effects and warning signs
This leaflet does not set out a separate list of serious side effects. The general warning signs below apply to any medicine.
General warning signs that apply to any medicine
Call for emergency help now if any of these happen
- Difficulty breathing, wheezing, or tightness in the throat or chest
- Swelling of the face, lips, tongue or throat
- A widespread rash with blistering or peeling skin, or sores in the mouth, eyes or genitals
- Fainting, collapse, or a sudden severe drop in alertness
- Chest pain, or sudden weakness or numbness on one side of the body
- A fit (seizure), or confusion that comes on suddenly
In South Africa call 10177 for an ambulance, or 112 from a mobile phone. Go to your nearest emergency department if it is faster. Do not wait to see whether the symptom settles.
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.
Evidence required before publish — source the following for flucloxacillin from the SAHPRA-approved patient information leaflet or professional information, and cite what you actually used.
- Anything the approved information for flucloxacillin says about how long specific effects last
- Whether the source describes any effect as usually temporary, or as needing review if it persists
- Whether any effect is described as continuing after the product is stopped
Factors that may affect side effects
The approved leaflet identifies the following cautions and factors.
Use with care, and tell your doctor, if
- Cross allergy between penicillin and cephalosporins may occur
- If you take SANDOZ FLUCLOXACILLIN by mouth, you may experience diarrhoea, feeling sick (nausea), heartburn and colic, pruritus ani, and disturbances of electrolyte balance
- If you have or develop diarrhoea
- If you suffer from liver problems, as this medicine could cause them to worsen
- If you are 50 years of age or older
- If you have been taking this medicine for a long time, as regular tests of liver and kidney function are advised
- If you suffer from kidney problems, as you may require a lower dose than normal (convulsions may occur very rarely in patients with kidney problems who take high doses). : : : Each capsule contains 250 mg flucloxacillin
- If you take SANDOZ FLUCLOXACILLIN over a long period, as you may experience an overgrowth of the natural organisms in your body, which may cause thrush infections
- If you are taking or will be taking paracetamol
- If you see signs and symptoms of severe skin reaction please inform you doctor or pharmacist Taking paracetamol at the same time as SANDOZ FLUCLOXACILLIN may result in a condition called high anion gap metabolic acidosis, which occurs when your body creates more acid and your blood becomes more acidic particularly in certain groups of patients at risk, e.g. patients with severe kidney problems, sepsis (a life threatening condition which occurs when the body reacts to an infection) or malnutrition, especially if the maximum daily doses of paracetamol are used. If you have taken paracetamol at the same time as SANDOZ FLUCLOXACILLIN, it is recommended that you are closely monitored to ensure that you do not develop high anion gap metabolic acidosis. High anion gap metabolic acidosis is a serious condition, which will require urgent medical treatment. Skin contact with the contents of the capsules should be avoided, as SANDOZ FLUCLOXACILLIN may irritate the skin. Children and adolescents SANDOZ FLUCLOXACILLIN is not recommended for use in children
Pregnancy and breastfeeding
- If you are pregnant or breastfeeding, think you may be pregnant or are planning to have a baby, please consult your doctor, pharmacist or other health care provider for advice before taking this medicine
- The safety of SANDOZ FLUCLOXACILLIN during pregnancy has not been established
- Do not use SANDOZ FLUCLOXACILLIN if you are pregnant
Interactions and medicines to check
The approved leaflet names these interactions.
- Methotrexate (a chemotherapy medicine used to treat certain cancers)
- Warfarin (medicine to prevent blood clotting) : : : Each capsule contains 250 mg flucloxacillin
- Probenecid or sulfinpyrazone (used to treat gout)
- Piperacillin (an antibiotic used to treat infections)
- Oral typhoid vaccine (antibiotics can make this less effective)
- Sugammadex (used with general anaesthetics)
- Other antibiotics (used to treat infections)
- Paracetamol
- Voriconazole (used to treat fungal infections)
Bring the actual products to the conversation
A pharmacist can check for interactions much faster from the packaging than from remembered names.
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
Do not stop a prescribed treatment on your own
Stopping some treatments suddenly causes its own problems, and the condition being treated may get worse. If you want to stop, ask a pharmacist or doctor how to do it safely — they can usually offer an alternative.
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.
Call for emergency help now if any of these happen
- Difficulty breathing, wheezing, or tightness in the throat or chest
- Swelling of the face, lips, tongue or throat
- A widespread rash with blistering or peeling skin, or sores in the mouth, eyes or genitals
- Fainting, collapse, or a sudden severe drop in alertness
- Chest pain, or sudden weakness or numbness on one side of the body
- A fit (seizure), or confusion that comes on suddenly
In South Africa call 10177 for an ambulance, or 112 from a mobile phone. Go to your nearest emergency department if it is faster. Do not wait to see whether the symptom settles.
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
If you are having thoughts of harming yourself
Help is available in South Africa. The SADAG helpline is 0800 567 567, or you can go to your nearest emergency department. You do not have to wait until it feels like an emergency.
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
Reporting is not a substitute for medical care
If someone is unwell now, get medical help first and report afterwards. Urgent symptoms always take precedence over paperwork.
For a fuller walkthrough see how to report an adverse drug reaction.
Related pages
← Back to more medicine side effects.
Report a side effect
If you think you have had a side effect, you can report a suspected side effect in South Africa. Report a suspected side effect through the appropriate SAHPRA pathway where relevant.
Information only
This page gives general medicine-safety information for people in South Africa. It is not a diagnosis and not personalised medical advice. It cannot tell you whether a symptom you are having is caused by a particular product. Speak to a pharmacist or doctor about your own situation, and do not stop or change a prescribed treatment on the basis of a web page.
Editorial status: draft — not for publication
Brief SE-00368 · build rank 368 · Phase 2 · Tier 2. Every evidence slot on this page must be completed from the SAHPRA-approved source and the page signed off by a qualified clinical or pharmacy reviewer before it is published. Target length 1,300–2,000 words.