166. Reduced Serum Penicillin (PCN-G) Levels Following Recommended Doses of Intramuscular Benzathine Penicillin G (BPG) in Active Adults: Clinical Implications
Session: Oral Abstract Session: Infectious Diseases Practice Challenges
Friday, October 21, 2011: 12:00 PM
Room: 151AB
Background: The likely extended absence of an approved and cost-effective group A streptococcal (GAS) vaccine means both primary and secondary prophylaxis for GAS infections will largely remain dependent on the widely recommended BPG. Additionally, published data confirm reduced eradication efficacy of GAS from the throat following BPG administration. Further concern is the possible effect of a recent change in BPG manufacturers in the US. We therefore measured serum PCN-G levels during a 4 week period after BPG administration.

Methods: Military consented basic trainees received 1,200,000 units of intramuscular BPG (Monarch/Pfizer Pharmaceuticals). Sera were obtained on staggered days from each subject 3 times during the 4 week follow-up. Serum samples were analyzed (blinded) by liquid chromatography/mass spectrometry analysis controlling for study cohort, BPG lot number, and body size (M2).

Results: 329 subjects [two cohorts (n=164 and 165)] were enrolled. Mean age was 20 years. Mean body weight was 75 kg. Serum PCN-G levels were <0.03, <0.02 and <0.01 µg/ml by days 9, 11 and 15 respectively.  50% of subjects had [serum] <0.03, <0.02 and <0.01 µg/ml by days 6, 9 and 16 respectively. There were no significant differences associated with cohort, BPG lot number, or body size. The half-life for serum PCN-G was 4.1 days.

Conclusion: In active young adults serum PCN-G levels were well below published (0.012, 0.016 µg/ml)and currently accepted PCN-G MIC90 values in less than 2.5 weeks. These data, along with recently published results reporting that currently recommended doses of BPG are associated with almost 40% failure to eradicate GAS from the throat, require serious reconsideration for future medical and public health recommendations/guidelines for GAS treatment and secondary prophylaxis for GAS infections in older adolescents/adults. Additional studies are needed in children and also for therapy of syphilis/yaws in adults.

Subject Category: J. Clinical practice issues

Michael Broderick, Ph.D.1, Christian Hansen, B.S.1, Kevin Russell, MD, MPH2,3, Edward Kaplan, MD, FIDSA4, Jeffrey Blumer, M.D., Ph.D.5 and Dennis Faix, MD MPH3, (1)Respiratory Diseases, Jackson Foundation at Naval Health Research Center, San Diego, CA, (2)GEIS, Armed Forces Health Surveillance Center, Silver Spring, MD, (3)Naval Health Research Center, San Diego, CA, (4)University of Minnnesota Medical School, Minneapolis, MN, (5)Department of Pediatrics, University of Toledo, Toledo, OH


M. Broderick, None

C. Hansen, None

K. Russell, None

E. Kaplan, None

J. Blumer, None

D. Faix, None

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