Formulary
Benzylpenicillin sodium: Indications, Dosing, Side Effects and Interactions
The penicillins are bactericidal and act by interfering with bacterial cell wall synthesis.
MedNext Academy | 6 min read
Benzylpenicillin sodium: Indications, Dosing, Side Effects and Interactions
The penicillins are bactericidal and act by interfering with bacterial cell wall synthesis.
Drug action
The penicillins are bactericidal and act by interfering with bacterial cell wall synthesis. They diffuse well into body tissues and fluids, but penetration into the cerebrospinal fluid is poor except when the meninges are inflamed. They are excreted in the urine in therapeutic concentrations.
Indications and dose
**Mild to moderate susceptible infections,Throat infections,Otitis media,Pneumonia,Cellulitis**
- **Adult** (By Intramuscular Injection): 0.6-1.2 g every 6 hours.
- **Adult** (By Slow Intravenous Injection, Or By Intravenous Infusion): 0.6-1.2 g every 6 hours, dose may be increased if necessary in more serious infections (consult product literature).
**Endocarditis (in combination with other antibacterial if necessary)**
- **Adult** (By Slow Intravenous Injection, Or By Intravenous Infusion): 1.2 g every 4 hours, increased if necessary to 2.4 g every 4 hours, dose may be increased in infections such as enterococcal endocarditis.
**Anthrax (in combination with other antibacterials)**
- **Adult** (By Slow Intravenous Injection, Or By Intravenous Infusion): 2.4 g every 4 hours.
**Intrapartum prophylaxis against group B streptococcal infection**
- **Adult** (By Slow Intravenous Injection, Or By Intravenous Infusion): Initially 3 g for 1 dose, then 1.5 g every 4 hours until delivery.
**Meningitis,Meningococcal disease**
- **Adult** (By Slow Intravenous Injection, Or By Intravenous Infusion): 2.4 g every 4 hours.
- **Neonate** (By Intravenous Infusion): 7 days to 28 days 50 mg/kg every 8 hours.
- **Child** (By Intravenous Infusion): 50 mg/kg every 4-6 hours (max. per dose 2.4 g).
**Suspected meningococcal disease [pre-hospital treatment]**
- **Neonate** (By Intravenous Injection, Or By Intramuscular Injection): 300 mg for 1 dose, administer prior to urgent transfer to hospital unless this will delay transfer.
- **Child** (By Intravenous Injection, Or By Intramuscular Injection): 10-17 years 1.2 g for 1 dose, administer prior to urgent transfer to hospital unless this will delay transfer.
- **Adult** (By Intravenous Injection, Or By Intramuscular Injection): 1.2 g for 1 dose, administer prior to urgent transfer to hospital unless this will delay transfer.
**Suspected bacterial meningitis [pre-hospital treatment where there is likely to be a clinically significant delay in transfer to hospital]**
- **Child** (By Intravenous Injection, Or By Intramuscular Injection): 10-17 years 1.2 g for 1 dose, administer prior to transfer to hospital.
- **Adult** (By Intravenous Injection, Or By Intramuscular Injection): 1.2 g for 1 dose, administer prior to transfer to hospital.
**Severe diphtheria [confirmed or probable] (in combination with a macrolide)**
- **Adult** (By Slow Intravenous Injection, Or By Intravenous Infusion): 1.2-2.4 g every 6 hours for 14 days.
**Mild to moderate susceptible infections, Throat infections, Otitis media, Pneumonia, Cellulitis for benzylpenicillin sodium**
- **Neonate up to 7 days** (By intramuscular injection, or by slow intravenous injection, or by intravenous infusion): 25 mg/kg every 12 hours; increased if necessary to 25 mg/kg every 8 hours, intravenous route recommended in neonates.
- **Neonate 7 days to 28 days** (By intramuscular injection, or by slow intravenous injection, or by intravenous infusion): 25 mg/kg every 8 hours; increased if necessary to 50 mg/kg every 8 hours in severe infection, intravenous route recommended in neonates.
- **Child** (By intramuscular injection, or by slow intravenous injection, or by intravenous infusion): 25 mg/kg every 6 hours; increased if necessary to 50 mg/kg every 4-6 hours (max. per dose 2.4 g) in severe infection, intravenous route recommended in infants.
**Endocarditis (in combination with other antibacterial if necessary) for benzylpenicillin sodium**
- **Child** (By slow intravenous injection, or by intravenous infusion): 25 mg/kg every 4 hours; increased if necessary to 50 mg/kg every 4 hours (max. per dose 2.4 g).
**Meningitis, Meningococcal disease for benzylpenicillin sodium**
- **Neonate up to 7 days** (By intravenous infusion): 50 mg/kg every 12 hours.
- **Neonate 7 days to 28 days** (By intravenous infusion): 50 mg/kg every 8 hours.
- **Child** (By intravenous infusion): 50 mg/kg every 4-6 hours (max. per dose 2.4 g).
**Suspected meningococcal disease [pre-hospital treatment] for benzylpenicillin sodium**
- **Neonate** (By intravenous injection, or by intramuscular injection): 300 mg for 1 dose, administer prior to urgent transfer to hospital unless this will delay transfer.
- **Child 1-11 months** (By intravenous injection, or by intramuscular injection): 300 mg for 1 dose, administer prior to urgent transfer to hospital unless this will delay transfer.
- **Child 1-9 years** (By intravenous injection, or by intramuscular injection): 600 mg for 1 dose, administer prior to urgent transfer to hospital unless this will delay transfer.
- **Child 10-17 years** (By intravenous injection, or by intramuscular injection): 1.2 g for 1 dose, administer prior to urgent transfer to hospital unless this will delay transfer.
**Suspected bacterial meningitis [pre-hospital treatment where there is likely to be a clinically significant delay in transfer to hospital] for benzylpenicillin sodium**
- **Child 1-11 months** (By intravenous injection, or by intramuscular injection): 300 mg for 1 dose, administer prior to transfer to hospital.
- **Child 1-9 years** (By intravenous injection, or by intramuscular injection): 600 mg for 1 dose, administer prior to transfer to hospital.
- **Child 10-17 years** (By intravenous injection, or by intramuscular injection): 1.2 g for 1 dose, administer prior to transfer to hospital.
**Neonatal sepsis for benzylpenicillin sodium**
- **Neonate up to 7 days** (By intramuscular injection, or by slow intravenous injection, or by intravenous infusion): 25 mg/kg every 12 hours; increased if necessary to 25 mg/kg every 8 hours, intravenous route recommended in neonates.
- **Neonate 7 days to 28 days** (By intramuscular injection, or by slow intravenous injection, or by intravenous infusion): 25 mg/kg every 8 hours; increased if necessary to 50 mg/kg every 8 hours in severe infection, intravenous route recommended in neonates.
**Severe diphtheria [confirmed or probable] (in combination with a macrolide) for benzylpenicillin sodium**
- **Child** (By slow intravenous injection, or by intravenous infusion): 25 mg/kg every 6 hours for 14 days; increased if necessary to 50 mg/kg every 4-6 hours (max. per dose 2.4 g).
Cautions
History of allergy Cautions For benzylpenicillin sodium Accumulation of sodium from injection can occur with high doses
Side effects
Common or very common Diarrhoea; hypersensitivity; nausea; skin reactions; thrombocytopenia; vomiting Uncommon Arthralgia; leucopenia Rare or very rare Agranulocytosis; angioedema; haemolytic anaemia; hepatic disorders; nephritis tubulointerstitial; neutropenia; pseudomembranous enterocolitis; seizure; severe cutaneous adverse reactions (SCARs) Side-effects, further information Diarrhoea frequently occurs during oral penicillin therapy. It is most common with broad-spectrum penicillins, which can cause antibiotic-associated colitis. Side-effects For benzylpenicillin sodium Common or very common Fever; Jarisch-Herxheimer reaction Rare or very rare Neurotoxicity Frequency not known Coma
Interactions
**Other interactions (2):**
- There is reduced excretion of methotrexate (and therefore increased risk of methotrexate toxicity) when used with benzylpenicillin sodium.
- Penicillins may interfere with: Urinary glucose test Coomb's tests Tests for urinary or serum proteins Tests which use bacteria e.g.
Pregnancy
Not known to be harmful.
Breast feeding
Trace amounts in milk, but appropriate to use.
Renal impairment
Accumulation of sodium from injection can occur in renal failure. High doses may cause neurotoxicity, including cerebral irritation, convulsions, or coma. Dose adjustments In adults: Reduce dose (consult product literature). M In children: Expert sources advise use normal dose every 8-12 hours if estimated glomerular filtration rate 10-50 mL/minute/1.73 m 2 ; use normal dose every 12 hours if estimated glomerular filtration rate less than 10 mL/minute/1.73 m 2 . See Prescribing in renal impairment .
Medicinal forms
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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