Benzylpenicillin (Penicillin G)

SPC §4.2. Other regimens stated: bacterial endocarditis — 7.2 to 12 g (12 to 20 mega units) or more daily in divided doses by the intravenous route, often by infusion. Meningococcal disease, adults and children over 12 years — 2.4 g every 4 hours. Suspected meningococcal disease (single pre-hospital dose given by the GP before transfer): 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. Prevention of Group B streptococcal disease of the newborn — a 3 g (5 mega units) loading dose to the mother initially, followed by 1.5 g (2.5 mega units) every 4 hours until delivery. ADMINISTRATION: the stated doses apply to both intramuscular and intravenous injection; alternate sites for repeated injections. High doses should be given by intravenous injection or infusion, with intravenous doses in excess of 1.2 g (2 mega units) 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. RECONSTITUTION (1200 mg vial): IV injection — dissolve in at least 8 mL Sodium Chloride Injection BP or Water for Injections BP; IV infusion — dissolve in at least 20 mL. Only freshly prepared solutions should be used; reconstituted solutions are intended for immediate administration. In renal failure and/or heart failure do not reconstitute in sodium-containing liquids such as Sodium Chloride Injection BP or Ringer's solution (sodium overload and/or heart failure may occur). High dosage may result in hypernatraemia and hypokalaemia unless the sodium content is taken into account. ELDERLY: elimination may be delayed and dose reduction may be necessary. SOURCE SCOPE: the SPC used is the general Benzylpenicillin sodium 1200 mg Powder for Injection label; it contains no ENT-specific posology, so dose is by indication and severity as above. SPC §4.5 (interactions) was truncated at the source-fetch limit and was not retrieved — interactions are therefore not recorded in this draft.

SPC §4.2 age bands as stated: children 1 month to 12 years — 100 mg/kg/day in 4 divided doses, not exceeding 4 g/day; infants 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. SUSPECTED MENINGOCOCCAL DISEASE (single dose before transfer to hospital): 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. Verify all paediatric doses against a children's formulary before prescribing.