PURBAC is a Schedule 4 (prescription-only) antibiotic used to treat a wide range of bacterial infections. It contains two active ingredients—sulfamethoxazole and trimethoprim—which work together to stop bacteria from multiplying and help your body clear infections effectively.
It is commonly prescribed in South Africa for infections affecting the lungs, urinary tract, digestive system, skin, and more. PURBAC is available as tablets and a paediatric liquid suspension.
What it is and what it is used for
Active ingredients and class
PURBAC contains:
- Trimethoprim
- Sulfamethoxazole
These belong to a group of medicines called antimicrobial agents, which are used to treat bacterial infections.
Understanding the infections PURBAC treats (brief descriptions)
Respiratory tract infections
These affect breathing passages and lungs:
- Bronchitis: Causes cough and mucus due to inflamed airways
- Sinusitis: Leads to facial pain and nasal congestion
- Tonsillitis: Causes sore throat and swollen tonsils
- Pneumonia: A serious lung infection causing fever, cough, and breathing difficulty
- Otitis media: Infection of the middle ear, often in children
Urinary and kidney infections
These affect the urinary system:
- Cystitis: Bladder infection causing burning urination
- Pyelonephritis: Kidney infection with fever and back pain
- Urethritis: Pain or irritation during urination
- Prostatitis: Infection of the prostate gland
Gastrointestinal infections
These affect the gut:
- Enteritis: Inflammation causing diarrhoea
- Typhoid/paratyphoid: Severe infections with high fever
- Bacillary dysentery: Bloody diarrhoea
- Cholera: Severe watery diarrhoea and dehydration
Genital infections
- Gonorrhoea: A sexually transmitted infection
- Other bacterial genital infections
Skin and soft tissue infections
- Boils and abscesses: Painful pus-filled swellings
- Pyoderma: Skin infection with sores
Other infections
- Brucellosis: Infection from animals or contaminated dairy
- Nocardiosis: Rare infection affecting lungs or skin
- Osteomyelitis: Bone infection
How it works
PURBAC blocks the production of folinic acid in bacteria—a substance they need to grow. Because it contains two medicines, it attacks bacteria at two stages, making it more effective at killing them.
Who should NOT use this medicine
Do not use PURBAC if you have:
- Allergy to sulphonamides or trimethoprim
- Severe liver or kidney disease
- Porphyria
- Megaloblastic anaemia
- Pregnancy or breastfeeding
- Premature or newborn infants
Warnings and precautions (Read before use)
- Higher risk of side effects in immunocompromised patients
- Caution in elderly individuals
- Risk of serious allergic reactions
- Possible blood disorders
- Kidney monitoring may be required
- Drink enough fluids
Driving: May cause dizziness or weakness
Pregnancy, planning pregnancy, and breastfeeding
- Pregnancy: Do not use
- Breastfeeding: Do not use
Interactions
May interact with:
- Warfarin
- Methotrexate
- Phenytoin
- Diuretics
- Diabetes medicines
- Digoxin and others
How to take (Step-by-step)
- Take every 12 hours
- Complete full course
Adults
- 2 ADULT tablets or 1 DOUBLE STRENGTH tablet
Children (6–12 years)
- 1 ADULT tablet
Suspension
- 10 ml twice daily
Duration
- Minimum 5 days
- Continue 2 days after symptoms improve
Dosing table
| Age/Condition | Dose | Frequency |
|---|---|---|
| Children (6–12 yrs) | 1 ADULT tablet | Every 12 hours |
| Adults | 2 ADULT or 1 DOUBLE STRENGTH | Every 12 hours |
| Severe cases | Higher dose | Every 12 hours |
| Suspension | 10 ml | Twice daily |
Possible side effects
Like all medicines, PURBAC can cause side effects. Some are mild and go away on their own, while others may be serious and require urgent medical attention.
Common side effects
These are more likely to occur and are usually mild:
- Skin rash:
A mild rash may appear as redness or small bumps. It often settles after stopping the medicine but should still be reported. - Nausea and vomiting:
Feeling sick or vomiting may occur, especially when starting treatment. - Diarrhoea:
Loose stools can happen as the medicine affects gut bacteria. - Headache:
Mild to moderate headaches may occur. - Dizziness:
You may feel light-headed or unsteady. - Insomnia (difficulty sleeping):
Some people may struggle to fall or stay asleep. - Fatigue (tiredness):
A general feeling of weakness or low energy.
What to do:
These effects are usually manageable. If they persist or worsen, contact your healthcare provider.
Less common side effects
Not specified in the source.
Serious side effects (seek urgent help)
These are rare but potentially life-threatening:
Severe allergic reactions
- Symptoms: swelling of face/throat, difficulty breathing, severe rash
- Conditions include:
- Anaphylaxis (severe allergic reaction)
- Stevens-Johnson syndrome
- Toxic epidermal necrolysis
Action: Stop the medicine immediately and go to a hospital.
Severe skin reactions
- Skin peeling, blistering, or painful rash
- May start with flu-like symptoms
Action: Urgent medical attention is required.
Blood disorders
- Aplastic anaemia: Reduced blood cell production
- Agranulocytosis: Low white blood cells, increasing infection risk
- Thrombocytopenia: Low platelets causing easy bruising or bleeding
Warning signs:
- Unusual bruising
- Persistent sore throat
- Fever
Kidney problems
- Crystalluria: Crystals forming in urine
- Kidney failure
Symptoms:
- Reduced urine output
- Pain in the lower back
- Swelling
Nervous system effects
- Peripheral neuritis: Tingling or numbness in hands/feet
- Optic neuropathy: Vision problems
Severe gastrointestinal conditions
- Pancreatitis: Severe abdominal pain
- Pseudomembranous colitis: Severe diarrhoea due to gut infection
Important safety advice
- Always report unusual symptoms early
- Do not ignore skin rashes
- Stay well hydrated
- Attend follow-up appointments if required
Storage and disposal
- Store below 25°C
- Protect from moisture and light
- Keep out of reach of children
What the medicine contains
Active ingredients
- Trimethoprim
- Sulfamethoxazole
Additional notes
- Tablets are sugar-free
- Suspension contains sucrose
Pack information and appearance
Available as:
- Adult tablets
- Double strength tablets
- Paediatric suspension
Practical FAQs
Can I stop early?
No, complete the full course.
What if I get a rash?
Stop the medicine and contact your doctor immediately.
Do I need to drink more water?
Yes, to protect your kidneys.
What if I feel dizzy?
Avoid driving and rest.
Can children take PURBAC?
Yes, with correct dosing.
Plain-language summary
PURBAC is a powerful antibiotic used to treat many types of bacterial infections. It works by stopping bacteria from growing and helps your body recover.
While many people tolerate it well, it can cause side effects ranging from mild stomach upset to serious allergic reactions. Always take it exactly as prescribed, stay hydrated, and seek medical help immediately if you notice severe symptoms such as rash, breathing difficulty, or unusual bruising.
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