Serum Penicillin G Levels Are Lower Than Expected in Adults within Two Weeks of Administration of 1.2 Million Units Penicillin G Levels over 4 Weeks
2011

Serum Penicillin G Levels After Injection

Sample size: 329 publication Evidence: moderate

Author Information

Author(s): Broderick Michael P., Hansen Christian J., Russell Kevin L., Kaplan Edward L., Blumer Jeffrey L., Faix Dennis J.

Primary Institution: Henry M. Jackson Foundation for the Advancement of Military Medicine, Naval Health Research Center, San Diego, California, United States of America

Hypothesis

How long do serum penicillin G levels remain adequate after administration of benzathine penicillin G?

Conclusion

Serum penicillin G levels fall below protective levels in healthy young adults within 2.5 weeks after injection.

Supporting Evidence

  • Serum penicillin G levels were measured at staggered time points over 4 weeks.
  • The half-life of serum penicillin G was found to be 4.1 days.
  • More than 50% of subjects had levels below protective thresholds by day 9.

Takeaway

When you get a shot of penicillin, it doesn't stay in your body long enough to help you after about two weeks.

Methodology

329 male military recruits received 1.2 million units of benzathine penicillin G and had their serum levels measured over 4 weeks.

Limitations

The study only included male military trainees and did not account for potential variations in penicillin bioavailability from different manufacturers.

Participant Demographics

All participants were male military trainees with a mean age of 20 years.

Statistical Information

Confidence Interval

95% confidence intervals were calculated for serum penicillin G levels.

Digital Object Identifier (DOI)

10.1371/journal.pone.0025308

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