Benzylpenicillin

Penicillin G

Systematic (IUPAC) name
(2S,5R,6R)-3,3-dimethyl-7-oxo-6-(2-phenylacetamido)-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid
Clinical data
AHFS/Drugs.com	Micromedex Detailed Consumer Information
MedlinePlus	a685013
Pregnancy cat.	B(US)
Legal status	℞ Prescription only
Routes	parenteral
Pharmacokinetic data
Protein binding	60 %
Metabolism	hepatic
Half-life	30 min
Excretion	renal
Identifiers
CAS number	61-33-6 Y (free acid) 69-57-8 (sodium salt)
ATC code	J01CE01 S01AA14 QJ51CE01
PubChem	CID 5904
DrugBank	DB01053
ChemSpider	5693 Y
UNII	Q42T66VG0C Y
KEGG	D02336 N
ChEBI	CHEBI:18208 N
ChEMBL	CHEMBL29 N
Chemical data
Formula	C16H18N2O4S
Mol. mass	334.4 g/mol
SMILES	eMolecules & PubChem
InChI InChI=1S/C16H18N2O4S/c1-16(2)12(15(21)22)18-13(20)11(14(18)23-16)17-10(19)8-9-6-4-3-5-7-9/h3-7,11-12,14H,8H2,1-2H3,(H,17,19)(H,21,22)/t11-,12+,14-/m1/s1 Y Key:JGSARLDLIJGVTE-MBNYWOFBSA-N Y
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Benzylpenicillin, commonly known as penicillin G, is the gold standard type of penicillin. 'G' in the name 'Penicillin G' refers to 'Gold Standard'. Penicillin G is typically given by a parenteral route of administration (not orally) because it is unstable in the hydrochloric acid of the stomach. Because the drug is given parenterally, higher tissue concentrations of penicillin G can be achieved than is possible with phenoxymethylpenicillin. These higher concentrations translate to increased antibacterial activity.

Medical uses

Specific indications for benzylpenicillin include:^[1]

• Cellulitis
• Bacterial endocarditis
• Gonorrhea
• Meningitis
• Aspiration pneumonia, lung abscess
• Community-acquired pneumonia
• Syphilis
• Septicemia in children
• Septic Arthritis
• Galactic Diarrhoea
• Gangrene

Adverse effects

Adverse affect can include hypersensitivity reactions including urticaria, fever, joint pains, rashes, angioedema, anaphylaxis, serum sickness-like reaction. Rarely CNS toxicity including convulsions (especially with high doses or in severe renal impairment), interstitial nephritis, haemolytic anaemia, leucopenia, thrombocytopenia, and coagulation disorders. Also reported diarrhoea (including antibiotic-associated colitis).

Toxicology

Benzylpenicillin serum concentrations can be monitored either by traditional microbiological assay or by more modern chromatographic techniques. Such measurements can be useful to avoid central nervous system toxicity in any patient receiving large doses of the drug on a chronic basis, but they are especially relevant to patients with renal failure, who may accumulate the drug due to reduced urinary excretion rates.^[2][3]

Compendial status

• British Pharmacopoeia ^[4]

References

1. ^ Rossi S, editor, ed (2006). Australian Medicines Handbook. Adelaide: Australian Medicines Handbook. ISBN 0-9757919-2-3. 
2. ^ Fossieck B Jr, Parker RH. Neurotoxicity during intravenous infusion of penicillin. A review. J. Clin. Pharmacol. 14: 504- 512, 1974.
3. ^ R. Baselt, Disposition of Toxic Drugs and Chemicals in Man, 8th edition, Biomedical Publications, Foster City, CA, 2008, pp. 1195-1196.
4. ^ British Pharmacopoeia Commission Secretariat. "Index (BP 2009)". http://www.pharmacopoeia.co.uk/pdf/2009_index.pdf. Retrieved 26 March 2010.