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Benzylpenicillin parenteral


Powder for solution for injection containing benzylpenicillin sodium

Drugs List

  • benzylpenicillin 1.2g powder for solution for injection
  • benzylpenicillin 600mg powder for solution for injection
  • Therapeutic Indications


    Anthrax: treatment
    Bacterial endocarditis
    Bacterial meningitis
    Infections sensitive to penicillin
    Meningococcal disease
    Neonatal group B streptococcal infections (intrapartum): prophylaxis
    Suspected meningococcal disease or meningitis

    Treatment of most wound infections, pyogenic infections of the skin, soft tissue infections and infections of the nose, throat, nasal sinuses, respiratory tract and middle ear.

    It is effective against many streptococcal (including pneumococcal), gonococcal and meningococcal infections.

    It is also indicated for treating the following infections caused by penicillin-sensitive organisms:
    Generalised infections
    Osteomyelitis (acute and chronic)
    Bacterial endocarditis (sub-acute)
    Suspected meningococcal disease or meningitis
    Gas gangrene
    Rat-bite fever
    Severe Lyme disease
    Brain abscesses
    Complications secondary to gonorrhoea and syphilis (e.g. gonococcal arthritis or endocarditis, and neurosyphilis)

    Prophylaxis of neonatal group B streptococcal infections (intrapartum)

    Treatment of congenital syphilis and neurosyphilis


    Susceptibility of the causative organism to the treatment should be tested, if possible, although therapy may be initiated before the results are available.


    Usually 600 to 3600 mg daily divided into 4 to 6 doses, depending on the infection.

    Serious infections including meningitis
    Up to 14.4 g per day in divided doses may be given by the intravenous route.

    Meningococcal disease
    2.4 g every 4 hours

    Suspected meningococcal disease
    1200 mg as a single dose, then immediately transport the patient to hospital.

    Bacterial endocarditis
    7.2 to 12 g or more daily in divided doses by the intravenous route, often by infusion.

    Gas gangrene
    Up to 43.2 g per day may be necessary for patients with rapidly spreading gas gangrene

    Anthrax (in combination with other antibacterials)
    2.4 g every 4 hours

    Prophylaxis of neonatal group B streptococcal infections (intrapartum)
    3 g loading dose to be administered to the mother, followed by 1.5 g every 4 hours until delivery.


    (See Dosage; Adult)


    Over 12 years
    (See Dosage; Adult)

    1 month to 12 years
    100 mg/kg/day in four divided doses, not exceeding 4 g/day.

    Bacterial endocarditis
    25 mg/kg every 4 hours.
    This may be increased if necessary to 50 mg/kg (maximum 2.4 g) every 4 hours.

    Meningococcal disease
    180 to 300 mg/kg/day in 4 to 6 divided doses. Not exceeding 12 g/day.

    Suspected meningococcal disease
    Administer a single dose as follows then immediately transport the patient to hospital.
    10 years and over: 1200 mg
    1 to 9 years: 600 mg
    1 month to 1 year: 300 mg


    Due to the reduced renal clearance in premature babies and neonates, there should be an interval of at least 8 to 12 hours between doses.

    Infants aged 1 to 4 weeks
    75 mg/kg/day in three divided doses.

    Meningococcal disease
    150 mg/kg/day in three divided doses.

    Suspected meningococcal disease
    300 mg as a single dose then immediately transport the patient to hospital.

    Neonates less than 7 days
    50 mg/kg/day in two divided doses.

    Meningococcal disease
    100 mg/kg/day in two divided doses.

    Suspected meningococcal disease
    300 mg as a single dose then immediately transport the patient to hospital.

    Patients with Renal Impairment

    For doses of 600 to 1200 mg, there should be an interval of at least 8 to 10 hours between doses.

    For higher doses required for treating more severe infection such as meningitis the dose and interval should be adjusted according to creatinine clearance:
    Creatinine clearance 125 ml/minute: 1.2 g every 2 hours or 1.8 g every 3 hours
    Creatinine clearance 60 ml/minute: 1.2 g every 4 hours
    Creatinine clearance 40 ml/minute: 900 mg every 4 hours
    Creatinine clearance 20 ml/minute: 600 mg every 4 hours
    Creatinine clearance 10 ml/minute: 600 mg every 6 hours
    Creatinine clearance nil: 300 mg every 6 hours or 600 mg every 8 hours

    Patients undergoing haemodialysis should receive an additional 300 mg dose every 6 hours during the dialysis session.

    If the patient has advanced hepatic disease with severe renal failure the dose should be reduced to 300 mg every 8 hours.

    Large doses of penicillin in the presence of impaired renal function, can cause cerebral irritation, convulsions and coma.

    Patients with Hepatic Impairment

    If the patients has advanced hepatic disease with severe renal failure the dose should be reduced to 300 mg every 8 hours.


    For intramuscular injection or intravenous injection or infusion.

    Only freshly prepared solutions should be used. Once reconstituted, solutions of benzylpenicillin sodium should be used immediately.

    Intravenous treatment is preferable in infants. This is because there is an increased risk of severe local reactions to intramuscular injections in these patients.

    For repeated injections, alternative sites should be used.

    Higher doses should be administered intravenously. Intravenous doses in excess of 1.2 grams should be given slowly, taking at least one minute for each 300 mg to avoid high levels causing irritation of the central nervous system and/or electrolyte imbalance.

    Take into account the sodium content of the injection as high doses of benzylpenicillin sodium may result in hypernatraemia and hypokalaemia.

    Benzylpenicillin should not be reconstituted in sodium-containing liquids (such as Sodium Chloride Injection BP or Ringer's solution) for patients with renal impairment or cardiac failure. This is because the excess sodium may lead to sodium overload or cardiac failure in these patients.


    None known

    Precautions and Warnings

    Allergic disposition
    Restricted sodium intake
    Diabetes mellitus
    Renal impairment
    Severe hepato-renal syndrome

    Contains more than 1 mmol (23 mg) sodium per dose
    Reduce dose and/or alter dose interval in patients with renal impairment
    Before initiating therapy enquire about previous hypersensitivity reactions
    Consult national/regional policy on the use of anti-infectives
    Avoid contact with skin or eyes
    Consider pseudomembranous colitis if patient presents with severe diarrhoea
    Monitor electrolyte balance when treatment exceeds 5 days
    Monitor for signs of superinfection with non-susceptible organisms
    Monitor haematological parameters when treatment exceeds 5 days
    Monitor patient for 30 minutes after administration
    Monitor renal function when treatment exceeds 5 days
    Prolonged use may result in superinfection with non-susceptible organisms
    May affect results of some laboratory tests
    Discontinue if drug-related rash or other hypersensitivity reactions occur
    Discontinue if severe and persistent diarrhoea develops

    Diabetic patients may experience delayed absorption following intramuscular injection.

    600 mg of benzylpenicillin sodium contains 1.68 mmol of sodium. Take into account the sodium content of the injection as high doses of benzylpenicillin sodium may result in hypernatraemia and hypokalaemia.
    Potassium-sparing diuretics may be beneficial. Where high doses are administered for more than 5 days, electrolyte balances, renal function and blood counts should be monitored.

    Pregnancy and Lactation


    Benzylpenicillin sodium is considered safe for use during 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.

    Reproduction studies in mice, rats and rabbits revealed no evidence of impaired fertility or foetal harm.

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).


    Benzylpenicillin sodium is considered safe for use in breastfeeding.

    Administration during breastfeeding is not known to be harmful, but Briggs suggests the following problems may exist for the nursing infant, modification of bowel flora, allergic response and interference with the interpretation of culture results if fever workup is required.

    It is not known whether benzylpenicillin sodium is excreted in human breast milk. However, it has been present in the milk of animals and trace amounts of other penicillins have been detected in human breast milk.

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at

    Side Effects

    Antibiotic-associated colitis
    CNS toxicity
    Coagulation disorders
    Haemolytic anaemia
    Hypersensitivity reactions
    Interstitial nephritis
    Jarisch-Herxheimer reaction
    Joint pain
    Overgrowth by non-susceptible organisms
    Pseudomembranous colitis
    Serum sickness-like reactions

    Effects on Laboratory Tests

    Benzylpenicillin administration may interfere with the following tests:
    Urinary glucose tests (false positive results if testing for reducing substances)
    Coomb's test
    Urinary or serum protein tests
    Tests that use bacteria (e.g. Guthrie test)


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: October 2014

    Reference Sources

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 9th edition (2011) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.

    Joint Formulary Committee. British National Formulary(online) London: BMJ Group and Pharmaceutical Press [Accessed on 9 October, 2014].

    Summary of Product Characteristics: Benzylpenicillin sodium powder for injection. Genus Pharmaceuticals. Revised June 2014.

    Paediatric Formulary Committee. BNF for Children (online) London: BMJ Group, Pharmaceutical Press, and RCPCH Publications [Accessed on 9 October, 2014].

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