Penicillin G Overview and Mechanism

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Questions and Answers

What could be a consequence of accidental injection into an artery?

Infection at the injection site

Skin irritation

Gangrene or tissue necrosis (correct)

Nerve damage

Clients with a history of PCN allergy should particularly avoid which type of medication due to cross-sensitivity?

Cephalosporins (correct)

Macrolides

Aminoglycosides

Tetracyclines

Which anticonvulsant effect may occur due to neurotoxicity from PCNs?

Increased appetite

Hallucinations (correct)

Fatigue

Nausea

What is a consideration for clients on sodium-restricted diets when using Sodium PCN G?

Sodium content may be problematic Signup and view all the answers

How frequently is the recommended dosing interval for adults taking PCN G?

Every 4 hours Signup and view all the answers

Which laboratory test should be monitored to assess renal function in clients using PCNs?

Basic Metabolic Panel (BMP) Signup and view all the answers

What should clients be instructed about regarding the full course of PCN treatment?

The entire course must be completed Signup and view all the answers

What is the reason concurrent use of bacteriostatic agents should be avoided with PCNs?

It reduces the effectiveness of PCN Signup and view all the answers

Which type of bacteria is penicillin G primarily active against?

Gram-positive cocci Signup and view all the answers

What is the primary mechanism of action for penicillin G?

Weakening the bacterial cell wall Signup and view all the answers

For which infection is penicillin G NOT considered the drug of choice?

Meningitis caused by Escherichia coli Signup and view all the answers

Which of the following uses of penicillin G involves prophylactic treatment?

Prevention of syphilis in exposed partners Signup and view all the answers

What is a common side effect associated with the administration of penicillin G?

Hypersensitivity reactions Signup and view all the answers

Which statement about penicillin G is true?

It is the preferred treatment for non-penicillinase producing N.gonorrhoeae. Signup and view all the answers

What is true about the effectiveness of penicillin G?

Only active against bacteria growing and dividing. Signup and view all the answers

What is one of the unique features of penicillin G?

It remains the drug of choice for many infections. Signup and view all the answers

Signup and view all the answers

Study Notes

Penicillin G (Benzylpenicillin) Overview

Category: Narrow-spectrum penicillin
Primary Function: Active against gram-positive bacteria, gram-negative cocci, anaerobic bacteria, and spirochetes. First-line treatment for gram-positive cocci infections.
Unique Features: First available penicillin, remains a drug of choice for many infections.

Mechanism of Action

Weaken bacterial cell wall, leading to excessive water uptake and rupture.
Achieved via inhibition of transpeptidases and disinhibition of autolysins, resulting in cell lysis and death.
Effective only against bacteria undergoing growth and division.

Indications and Therapeutic Uses

Gram-Positive Cocci Infections: Treatment of infections caused by Streptococcus pneumoniae, Streptococcus pyogenes (pharyngitis), and Streptococcus viridans (infectious endocarditis).
Gram-Positive Bacilli Infections: Preferred for infections like gas gangrene, tetanus, and anthrax.
Meningitis: Effective against N. meningitidis
Gonorrhea: Effective against non-penicillinase producing strains of N. gonorrhoeae.
Syphilis: Treatment for T. pallidum and prevention in exposed partners.
Rheumatic Fever: Prophylaxis and treatment of recurrent rheumatic fever.
Bacterial Endocarditis: Used in prophylaxis for individuals with prosthetic heart valves, congenital heart disease, acquired valvular heart disease, mitral valve prolapse, and those with a history of bacterial endocarditis.

Side Effects and Adverse Reactions

Hypersensitivity: Most concerning adverse reaction.
Injection Site Reaction: Pain at injection site; risk of gangrene or tissue necrosis with arterial injection; peripheral nerve dysfunction with accidental nerve injection.
Neurotoxicity: Seizures, confusion, or hallucinations with toxicity.

Precautions and Contraindications

Penicillin Allergy: Consider clients with a penicillin allergy allergic to all penicillin agents.
Cross-sensitivity to Cephalosporins: Risk of low (1%) cross-sensitivity to cephalosporins, particularly in those with severe/immediate (anaphylactic) immune responses.
Sodium Restriction: Use sodium-containing penicillin (e.g., sodium PCN G) with caution in clients with sodium-restricted diets.

Drug Interactions

Concurrent use of bacteriostatic agents (e.g., tetracyclines) may reduce penicillin's bactericidal effects and should be avoided.

Dosing, Administration, & Client Teaching

Dosing: Varies based on condition, severity, and client response; check drug dosing guidelines.
Administration: Intravenous (IV) or intramuscular (IM) administration; different salts affect absorption rate.
Client Education: Emphasize completing the full course of treatment. Educate clients regarding potential side effects and monitoring parameters, and when to report to a healthcare provider.

Labs to Monitor

Basic Metabolic Panel (BMP): Monitor renal function (BUN/Creatinine, Creatine Clearance) as renal impairment dramatically increases PCN half-life and may necessitate dosage reduction.

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Description

This quiz provides an overview of Penicillin G, including its classification as a narrow-spectrum penicillin and its mechanism of action against bacterial infections. It covers therapeutic uses primarily against gram-positive bacteria, detailing its effectiveness and the conditions treated. Test your knowledge on this essential antibiotic!