Brands, Medical Use, Clinical Data
Drug Category
- Anti-bacterial Agents
- Penicillins
Dosage Forms
- Powder for solution
- Suspension
- Tablet
Brands / Synonyms
Abbocillin; Ayercillin; Benzopenicillin; Benzylpenicillin; Benzylpenicillin G; Benzylpenicillinic Acid; Bicillin; Bicillin CR; Bicillin L-A; Cillora; Cilloral; Cilopen; Compocillin G; Cosmopen; Crysticillin 300 A.S.; Dropcillin; Duracillin A.S.; Free Benzylpenicillin; Free Penicillin G; Free Penicillin Ii; Galofak; Gelacillin; Liquacillin; Megacillin; Pencillin G; Penicillin; Penicillin G; Penicillin G Potassium; Penicillin G Potassium in Plastic Container; Penicillin G Procaine; Penicillin G Sodium; Penicillin-G Potassium; Penicillinic Acid, Benzyl-; Pentids; Pentids '200'; Permapen; Pfizerpen; Pfizerpen G; Pfizerpen-As; Pharmacillin; Phenylacetamidopenicillanic Acid; Pradupen; Specilline G; Ursopen; Wycillin
Indications
For use in the treatment of severe infections caused by penicillin G-susceptible microorganisms when rapid and high penicillin levels are required.
Pharmacology
Penicillin G is a penicillin beta-lactam antibiotic used in the treatment of bacterial infections caused by susceptible, usually gram-positive, organisms. The name "penicillin" can either refer to several variants of penicillin available, or to the group of antibiotics derived from the penicillins. Penicillin G has in vitro activity against gram-positive and gram-negative aerobic and anaerobic bacteria. The bactericidal activity of penicillin G results from the inhibition of cell wall synthesis and is mediated through penicillin G binding to penicillin binding proteins (PBPs). Penicillin G is stable against hydrolysis by a variety of beta-lactamases, including penicillinases, and cephalosporinases and extended spectrum beta-lactamases.
Mechanism of Action
By binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, penicillin G inhibits the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins; it is possible that penicillin G interferes with an autolysin inhibitor.
Absorption
Rapidly absorbed following both intramuscular and subcutaneous injection. Initial blood levels following parenteral administration are high but transient.
Toxicity
Oral LD50 in rat is 8900 mk/kg. Neurological adverse reactions, including convulsions, may occur with the attainment of high CSF levels of beta-lactams.
Biotrnasformation / Drug Metabolism
Not Available
Contraindications
A history of a previous hypersensitivity reaction to any penicillin is a contraindication.
Drug Interactions
Concurrent administration of bacteriostatic antibiotics (e.g., erythromycin, tetracycline) may diminish the
bactericidal effects of penicillins by slowing the rate of bacterial growth. Bactericidal agents work most
effectively against the immature cell wall of rapidly proliferating microorganisms. This has been demonstrated in
vitro; however, the clinical significance of this interaction is not well documented. There are few clinical
situations in which the concurrent use of ''static'' and ''cidal '' antibiotics are indicated. However, in selected
circumstances in which such therapy is appropriate, using adequate doses of antibacterial agents and beginning
penicillin therapy first, should minimize the potential for interaction.
Penicillin blood levels may be prolonged by concurrent administration of probenecid which blocks the renal tubular
secretion of penicillins.
Displacement of penicillin from plasma protein binding sites will elevate the level of free penicillin in the
serum.
|
