Patient leaflets and SmPCs, drug interaction checker, official and paediatric dosages, pregnancy and breastfeeding guidance, and NHS pharmacy opening hours — all in one place.
Patient leaflets and SmPCs, drug interaction checker, official and paediatric dosages, pregnancy and breastfeeding guidance, and NHS pharmacy opening hours — all in one place.
Benzylpenicillin sodium 600 mg and 1200 mg powder for solution for injection or infusion is referred to as "Benzylpenicillin Injection" in this leaflet. It contains benzylpenicillin sodium, also known as penicillin G. Benzylpenicillin sodium is one of a group of medicines known as penicillins, which are antibiotics. Antibiotics are used to kill the bacteria (germs) which cause infections. Benzylpenicillin Injection is used to treat infections of the ear, nose, throat, chest, heart, bones and skin. It may also be used to treat:
• some sexually transmitted infections (gonorrhoea and syphilis), • meningitis, • brain abscesses, • gangrene (decay and death of tissue due to lack of blood supply), • blood infections, • anthrax (an infection from animals), • tetanus, • diphtheria (acute infections/disease of the respiratory tract), • listeria (a type of food poisoning), • leptospirosis (an infection from animals), • pasteurellosis (an infection following animal bites), • severe Lyme disease (an infection from tick bites), • actinomycosis (an infection caused by trauma/surgery) • some infections caused by rat bites. Benzylpenicillin Injection is also used for the prevention of infection in newborn babies (specifically group B streptococcal infection).
PACKAGE LEAFLET: INFORMATION FOR THE USER
The usual dose is 600 mg to 3,600 mg daily. For severe infections such as meningitis and gangrene, higher daily doses of up to 14,400 mg and 43,200 mg respectively may be used. Suspected Meningitis This medicine is sometimes given as a single injection in cases of suspected meningitis. The usual dose is 1,200mg for adults and children over 10 years. Meningitis The usual dose is 2,400mg every four hours for adults. Prevention of infection during labour If the injection is administered during labour for the prevention of infection in newborn babies (specifically group B streptococcal infection), 3,000mg should be given to the mother followed by 1,500mg every four hours until the baby is delivered. Adults with kidney problems Your doctor will carry out some tests to check this. You may then be given a lower dose of this Injection. Lower doses may also be given to some elderly patients. Children The dose for babies and children is based on their weight. The usual dose for newborn babies is 50 mg per kg of their body weight per day. For infants (1 to 4 weeks old), the usual dose is 75 mg per kg of their body weight per day. The usual dose for children is 100 mg per kg of their body weight per day although higher doses of up to 4,000 mg per day may be given. The daily dose may be divided into between two and six separate injections. Higher doses for severe infections are usually given by slow intravenous infusion (drip). Meningitis The usual dose is 180-300mg per kg per day (up to 12g per day) for children up to 12 years old, 150mg per kg per day for infants (1 to 4 weeks old) and 100mg per kg per day for newborn babies. Premature babies and neonates Lower doses may also be given to these groups. If you take more Benzylpenicillin Injection than you should Irritation of the brain and shaking fits (convulsion) have been seen in patients when very high doses of this medicine have been given by mistake, in particular to patients with poor kidney function.
Like all medicines, this medicine can cause side effects, although not everybody gets them. Tell your doctor immediately if you get any of the following side effects:
• skin rash or itchy skin • difficulty in breathing or tightness of the chest • puffiness of the eyelids, face or lips • swelling or redness of the tongue • fever • joint pains
• swollen lymph nodes. The following side effects have also been reported after either long-term use or with high doses of your medicine:
• reduction in blood cell count and anaemia, which might make you feel tired or dizzy • low levels of potassium in the blood • high levels of sodium in the blood • inflammation of the kidney • skin irritation, fever, headache, sore throat, sore muscles and fast heartbeat particularly in patients being treated for syphilis (a sexually transmitted disease) • diarrhoea, which may rarely have blood in it • thrush or other infections • fits (convulsions). Other side effects (it is not known how frequently these side effects may occur):
• AGEP – Acute Generalized Exanthematous Pustulosis with symptoms such as severe drug skin reactions with or without reddening of the skin, fever, pustules • maculo-papular rash (flat and red area on the skin) • rash morbilliform (rash that looks like measles), • itching • erythema (inflammatory reddening of the skin) • angioedema (swelling of the skin, mucosa and subcutaneous tissue, generally located on the face, mouth or tongue) • thrombocytopenia (reduced blood levels of platelets) • anaemia (reduced blood levels of red blood cells) • metabolic encephalopathy (neurological disorders with convulsions and loss of consciousness). Reporting of side effects If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects, you can help provide more information on the safety of this medicine.
Benzylpenicillin Injection is a white, crystalline powder supplied in two strengths (600 mg and 1200 mg) in a rubber stoppered glass vial. Pack sizes: 10 vials. Marketing Authorisation Holder and Manufacturer Istituto Biochimico Italiano G. Lorenzini S.p.A. Via Fossignano 2 04011 Aprilia (LT) Italy This leaflet was last revised in 11/2025. .
------------------------------------------------------------------------------------------------------------------------------------ The following information is intended for medical or healthcare professionals only Preparation of solutions: Only freshly prepared solutions should be used. Reconstituted solutions of benzylpenicillin sodium are intended for immediate administration. Intravenous Injection: 600mg vial: Dissolve 600 mg (1 mega unit) in 4 ml of Water for Injection or Sodium Chloride Injection (displacement value: approximately 0.4 ml). 1200mg vial: Dissolve 1200 mg (2 mega units) in at least 8 ml of Sodium Chloride Injection or Water for Injection (displacement value: approximately 0.8 ml). For lower concentrations, draw up the entire contents of the vial and dilute to 10 ml (600mg vial) or 20 ml (1200mg vial) with Water for Injection or Sodium Chloride Injection. Intravenous Infusion: 600mg vial: Dissolve 600 mg (1 mega unit) in at least 10 ml of Sodium Chloride Injection or Water for Injection. 1200mg vial: Dissolve 1200 mg (2 mega units) in at least 20 ml of Sodium Chloride Injection or Water for Injection. Intramuscular injection: 600mg vial: Dissolve 600 mg (1 mega unit) in 1.6 to 2.0 ml of Water for Injection.
Benzylpenicillin sodium 1200mg Powder for solution for injection/infusion vials comes as powder containing 1200mg. Always follow the dose your doctor or pharmacist has given you, and read the leaflet that comes with the medicine.
The active substance in Benzylpenicillin sodium 1200mg Powder for solution for injection/infusion vials is benzylpenicillin sodium.
Medicines with the same active substance include: Benzylpenicillin sodium 1200mg Powder for Injection, Benzylpenicillin sodium 600mg Powder for Injection. They are interchangeable only if your prescriber or pharmacist says so.
This leaflet reproduces the patient information leaflet approved for Benzylpenicillin sodium 1200mg Powder for solution for injection/infusion vials, as published on the electronic medicines compendium (emc). The version printed inside your medicine’s packaging is the one that applies to you.
Whether a medicine is available over the counter or on prescription only depends on its licence. Check the leaflet, or ask your pharmacist — they can tell you straight away.
The text above reproduces the patient information leaflet approved for this medicine, restructured for easier reading.
Benzylpenicillin is indicated for:
• most wound infections,
• pyogenic infections of the skin,
• soft tissue infections
• infections of the nose, throat, nasal sinuses, respiratory tract and middle ear, etc.
It is also indicated for the following infections caused by penicillin-sensitive microorganisms:
• Generalised infections, septicaemia and pyaemia from susceptible bacteria.
• Acute and chronic osteomyelitis, sub-acute bacterial endocarditis and meningitis caused by susceptible organisms.
• Suspected meningococcal disease.
• Gas gangrene, tetanus, actinomycosis, anthrax, leptospirosis, rat-bite fever, listeriosis, severe Lyme disease, and prevention of neonatal group B streptococcal infections.
• Complications secondary to gonorrhoea and syphilis (e.g. gonococcal arthritis or endocarditis, congenital syphilis and neurosyphilis).
• Diphtheria, brain abscesses and pasteurellosis.
Consideration should be given to official local guidance (e.g. national recommendations) on the appropriate use of antibacterial agents.
Susceptibility of the causative organism to the treatment should be tested (if possible), although therapy may be initiated before the results are available.
Posology
The following dosages apply.
Alternate sites should be used for repeated injections.
Adults
600 to 3,600 mg (1 to 6 mega units) daily, divided into 4 to 6 doses, depending on the indication. Higher doses (up to 14.4 g/day (24 mega units) in divided doses) may be given in serious infections such as adult meningitis by the intravenous route.
In bacterial endocarditis, 7.2 to 12 g (12 to 20 mega units) or more may be given daily in divided doses by the intravenous route, often by infusion.
Doses up to 43.2 g (72 mega units) per day may be necessary for patients with rapidly spreading gas gangrene.
High doses should be administered by intravenous injection or infusion, with intravenous doses in excess of 1.2g (2 mega units) being given slowly, taking at least one minute for each 300 mg (0.5 mega unit) to avoid high levels causing irritation of the central nervous system and/or electrolyte imbalance.
For the prevention of Group B Streptococcal disease of the newborn, a 3 g (5 mega units) loading dose should be given to the mother initially, followed by 1.5 g (2.5 mega units) every 4 hours until delivery.
Paediatric patients
Pediatric doses are generally determined on a weight basis and should be calculated for each patient individually.
Children aged 1 month to 12 years
100 mg/kg/day in 4 divided doses; not exceeding 4 g/day.
Infants aged 1-4 weeks
75 mg/kg/day in 3 divided doses.
Newborn Infants
50 mg/kg/day in 2 divided doses.
Meningococcal disease
| Children 1 month to 12 years: | 180-300 mg/kg/day in 4-6 divided doses, not exceeding 12 g/day. |
| Infants 1-4 weeks: | 150 mg/kg/day in 3 divided doses. |
| Newborn infants: | 100 mg/kg/day in 2 divided doses. |
| Adults and children over 12 years: | 2.4 g every 4 hours |
Suspected meningococcal disease
If meningococcal disease is suspected general practitioners should give a single dose of benzylpenicillin sodium, before transferring the patient to hospital, as follows:
| Adults and children over 10 years: | 1,200 mg IV (or IM) |
| Children 1-9 years: | 600 mg IV (or IM) |
| Children under 1 year: | 300 mg IV (or IM) |
Premature babies and neonates
Dosing should not be more frequent than every 8 or 12 hours in this age group, since renal clearance is reduced at this age and the mean half-life of benzylpenicillin may be as long as 3 hours.
Since infants have been found to develop severe local reactions to intramuscular injections, intravenous treatment should preferably be used.
Special populations
Patients with renal insufficiency
For doses of 0.6-1.2 g (1-2 mega units) the dosing interval should be no more frequent than every 8-10 hours.
For high doses e.g. 14.4 g (24 mega units) required for the treatment of serious infections such as meningitis, the dosage and dose interval of benzylpenicillin sodium should be adjusted in accordance with the following schedule:
| Creatinine clearance (ml per minute) | Dose (g) | Dose (mega units) | Dosing interval (hours) |
| 125 | 1.2 or 1.8 | 2 or 3 | 2
3 |
| 60 | 1.2 | 2 | 4 |
| 40 | 0.9 | 1.5 | 4 |
| 20 | 0.6 | 1.0 | 4 |
| 10 | 0.6 | 1.0 | 6 |
| Nil | 0.3 or 0.6 | 0.5 or 1.0 | 6 8 |
The dose in the above table should be further reduced to 300 mg (0.5 mega units) 8 hourly if advanced liver disease is associated with severe renal failure.
If haemodialysis is required, an additional dose of 300 mg (0.5 mega units) should be given 6 hourly during the procedure.
Elderly patients
Elimination may be delayed in elderly patients and dose reduction may be necessary.
Method of administration
For intravenous use.
For instructions on reconstitution of the medicinal product before administration, see section 6.6.
• Hypersensitivity to penicillins or any of the excipients.
• History of a severe immediate hypersensitivity reaction (e.g. anaphylaxis) to another beta lactam agent (e.g. a cephalosporin, carbapenem or monobactam).
There is reduced excretion of methotrexate (and therefore increased risk of methotrexate toxicity) when used with benzylpenicillin sodium.
Probenecid inhibits tubular secretion of benzylpenicillin sodium and so may be given to increase the plasma concentrations.
Penicillins may interfere with:
• Urinary glucose test
• Coomb's tests
• Tests for urinary or serum proteins
• Tests which use bacteria e.g. Guthrie test.
Pregnancy
Benzylpenicillin sodium has been taken by a large number of pregnant women and women of childbearing age without an increase in malformations or other direct or indirect harmful effects on the foetus having been observed.
Breast-feeding
Although it is not known if benzylpenicillin sodium may be excreted into the breast milk of nursing mothers, it is actively transported from the blood to milk in animals and trace amounts of other penicillins in human milk have been detected.
Fertility
Reproduction studies in mice, rats and rabbits have not produced evidence of any negative effects on male and female fertility.
None
Excessive blood levels of benzylpenicillin sodium can be corrected by haemodialysis.
Ask anything about Benzylpenicillin sodium 1200mg Powder for solution for injection/infusion vials. The assistant answers only from this leaflet — if the leaflet does not cover it, it will say so. It does not give medical advice.
Answers come from the patient leaflet published on the electronic medicines compendium (emc). They are not medical advice. Ask a pharmacist or your GP if you are unsure. For urgent help call NHS 111, or 999 in an emergency.
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