Beta Lactamase Inhibitors and Adverse effects of Penicillins

Beta Lactamase Inhibitors and Adverse effects of Penicillins


       β-Lactamase inhibitors

       Adverse effects of penicillins

       Drug interactions of penicillins

At the end of this lecture, the student will be able to:

       Describe the mechanism of action of β-Lactamase inhibitors

       Discuss the adverse effects of penicillins

       Explain the drug reactions of penicillins

β-Lactamase Inhibitor

       Resembles β-Lactam antibiotics in structure

       No significant antimicrobial action

       Binds irreversibly to catalytic site of β-lactamase

       Prevent hydrolysis of penicillins

       Inhibit plasmid mediated β-lactamase

       Also called as “suicidal inhibitors”

Development of Penicillin Resistance by β-Lactamase

Mechanism of Action of β-Lactamase Inhibitor 

β-Lactamase Inhibitor

       Unable to inhibit chromosomally mediated β-Lactamase found in Enterobacter, pseudomonos aeruginosa, Citrobacter, Serratia


       Clavulanic acid (derived from Streptomyces clavligerus)

       Sulbactam (semisynthetic)

       Tazobactam (structural analogue of sulbactam)

       Clavulanic acid – orally absorbed

       Clavulanic acid is combined with amoxycillin

       Sulbactam with ampicillin

       Tazobactam with piperacillin

       Addition of clavulinic acid to amoxycillin – extends antimicrobial spectrum of amoxycillin

Adverse Effects of Penicillin

Hypersensitivity reaction

       Penicilloic acid and benzyl penicillin contribute to hypersensitivity

       Classified as immediate, accelerated and late hypersensitivity reactions

Immediate hypersensitivity

       Occurs within 20 min of administration of penicillin injection

       Characterised by the presence of IgE Abs

       Formed against benzyl penicillin

       Manifestation – Urticaria, rashes, pruritis, wheezing and rhinitis and anaphylactic shock

Accelerated hypersensitivity

       Formation of IgE Ab against penicilloic acid

       Occurs in 72 h of administration

       Rarely fatal

       Rashes, itching, Fever. No much respiratory depression

Late hypersensitivity

       Occurs after 72 h

       Presence of IgE and IgM Ab against penicilloic acid

Symptoms include local inflammatory reactions like



       Serum sickness

       Haemolytic anemia

GIT effects




       Abnormal taste sensation


       β-lactamase inhibitor resembles β-Lactam antibiotics in structure that binds irreversibly to catalytic site of β-lactamase and prevent hydrolysis of penicillins

       They do not show any  significant antimicrobial action

       Includes clavulinic acid, Sulbactam and tazobactam

       Penicillin is associated with a no. of adverse effects hypersensitivity being the major one


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