What is Crystapen (Benzylpenicillin)?

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Last updated: April 17, 2025View editorial policy

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From the Guidelines

Crystapen is a brand name for benzylpenicillin (also known as penicillin G), an antibiotic used to treat various bacterial infections, and its use is supported by guidelines for the treatment of group A streptococcal pharyngitis, as seen in the recommendations from the American Heart Association 1.

Key Points About Crystapen

  • It is typically administered by injection, either intramuscularly or intravenously, and is not available in oral form because stomach acid would destroy it.
  • Crystapen is effective against many gram-positive bacteria and some gram-negative bacteria, making it useful for treating conditions like pneumonia, meningitis, endocarditis, and severe skin infections.
  • The typical adult dose ranges from 1.2 to 2.4 grams daily, divided into 4-6 doses, though this varies based on infection severity and type, with specific dosing recommendations provided for the treatment of streptococcal pharyngitis, such as 600,000 U for patients ≤27 kg and 1,200,000 U for patients >27 kg for benzathine penicillin G 1.
  • Treatment duration typically ranges from 5-14 days depending on the condition being treated.
  • Crystapen works by interfering with bacterial cell wall synthesis, causing the bacteria to rupture and die.

Important Considerations

  • Some patients may be allergic to penicillin, and a thorough allergy history should be taken before administration, with alternative treatments available for those with penicillin allergy, such as narrow-spectrum cephalosporins or clindamycin 1.
  • Kidney function should be monitored during treatment as the medication is primarily excreted through the kidneys.
  • The choice of antibiotic should consider factors such as bacteriologic and clinical efficacy, ease of adherence, cost, spectrum of activity, and potential side effects, with benzathine penicillin G and oral penicillin V being recommended for the treatment of group A streptococcal pharyngitis, except in individuals with histories of penicillin allergy 1.

From the Research

Definition of Crystapen

  • There is no direct information available in the provided studies to define what Crystapen is.
  • The studies primarily focus on antibiotic treatments, resistance, and effectiveness against various bacterial infections, including those caused by Group A Streptococcus 2, 3, 4, 5, 6.
  • Without specific details or context about Crystapen from the given evidence, it's challenging to provide a precise definition or description of what it might be.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Erythromycin in the treatment of streptococcal infections.

Pediatric infectious disease, 1986

Research

Antibiotic use: present and future.

The new microbiologica, 2007

Research

Different antibiotic treatments for group A streptococcal pharyngitis.

The Cochrane database of systematic reviews, 2021

Research

Patterns of Antibiotic Nonsusceptibility Among Invasive Group A Streptococcus Infections-United States, 2006-2017.

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2021

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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