benzylpenicillin

Action and Spectrum

Actions and Spectrum   

Action: 

It is effective against bacteria as it has a killing action on bacteria commonly termed as bactericidal. This is achieved through inhibiting enzymes necessary for formation of a bacterial cell wall, lead to rupture of bacterial cell wall and death of the bacterial cell.
It is a beta-lactam antibiotic, which works through the interaction of enzymes known as specified penicillin-binding proteins (PBPs) in bacterial cells. PBPs are enzymes which are related to cell wall synthesis therefore, compounds that affect this enzyme slow the process of cell wall formation. Thus, this action makes the bacterial cell wall less permeable and makes it more susceptible to osmotic pressure and cell lysis. 

Spectrum:
Benzylpenicillin effectiveness is limited to Gram-positive and certain Gram-negative bacteria. 

Drug Interaction

Adverse Reaction

Frequency not defined  

Nausea  

Black or hairy tongue  

Serum-like sickness  

Vomiting  

Stomatitis  

Convulsions  

Rash  

Fever  

Interstitial nephritis  

Leucopenia  

Thrombocytopenia haemolytic anemia  

Granulocytopenia  

Agranulocytosis  

Black Box Warning

Black Box Warning   

None  

Contraindication / Caution

Contraindication/Caution:  

Contraindications:  

Allergy to penicillins  

Hypersensitivity  

Cautions:  

Renal impairment  

Hepatic impairment  

Individual sensitivity  

Gastrointestinal disorders  

Pregnancy  

Lactation  

Pregnancy / Lactation

Pregnancy/Lactation   

Pregnancy consideration:   

Pregnancy Category: B  

Breastfeeding warnings:   

No data is available.  

Pregnancy category:  

Category A: Satisfactory and well-controlled studies show no risk to the fetus in the first or later trimester.  

Category B: No evidence of risk to the fetus is found in animal reproduction studies, and there are not enough studies on pregnant women.  

Category C: Adverse effects on the fetus found with evidence in animal reproduction studies and no adequate evidence for a human product; Pregnant women must take care of the potential risks.  

Category D: There is adequate data with sufficient evidence of human fetal risk from various platforms. However, despite potential dangers may be used only in emergencies for potential benefits.  

Category X: Drugs listed in this category outweigh the risks over benefits. The drug is not for pregnant women.  

Category N: No data for the drug under this category is available.  

Pharmacology

Pharmacology   

The mechanism of action of benzylpenicillin is to interfere with the synthesis of cell wall in bacteria. It is specific to the enzymes known as penicillin-binding proteins which are located on the bacterial cell wall. 

Pharmacodynamics:  

Certain bacteria develop beta-lactamase enzymes, which can break down benzylpenicillin. 

These enzymes can hydrolyze the beta-lactam ring of penicillins thus becoming ineffective to the bacteria. This resistance mechanism is often addressed through the co-administration of beta-lactamase inhibitors such as clavulanic acid in combination with benzylpenicillin within products like amoxicillin/clavulanate.  

The beta-lactamase enzyme is rendered inactive by the beta-lactamase inhibitor, maintaining the efficacy of benzylpenicillin.  

Pharmacokinetics:  

Absorption
Benzylpenicillin can be administered through the intramuscular and intravenous route because it has poor bio availability through the oral route. 

Distribution
In the bloodstream benzylpenicillin distributes to all parts of the body including the cerebrospinal fluid area which is useful in treating central nervous system infections.
Metabolism
Benzylpenicillin undergo minimal metabolism. 

Excretion and Elimination
Benzylpenicillin is filtered in urine by the kidneys, and possess short biological half-life, ranging from 0.5 to 1 hour in a person with normal renal function. 

Adminstartion

Administration   

Benzylpenicillin is typically administered parenterally through intramuscular or intravenous injection.  

Patient Information Leaflet

Patient information leaflet  

Generic Name: benzylpenicillin  

Why do we use benzylpenicillin?  

Benzylpenicillin commonly called as Penicillin G, its wide usage and effectiveness in treating most types of bacterial infections. This was among the oldest of the discovered antibiotics and it is now one of the required antibiotics in the therapeutic area.