Penicillin G Treatment in Infective Endocarditis Patients - Does Standard Dosing Result in Therapeutic Plasma Concentrations?

Abstract

Penicillin G is frequently used to treat infective endocarditis (IE) caused by streptococci, penicillin-susceptible staphylococci and enterococci. Appropriate antibiotic exposure is essential for survival and reduces the risk of complications and drug resistance development. We determined penicillin G plasma concentration [p-penicillin] once weekly in 46 IE patients. The aim was to evaluate whether penicillin G 3 g every 6 hr (q6 h) resulted in therapeutic concentrations and to analyse potential factors that influence inter- and intra-individual variability, using linear regression and a random coefficient model. [P-penicillin] at 3 hr and at 6 hr was compared with the minimal inhibitory concentration (MIC) of the bacteria isolated from blood cultures to evaluate the following PK/PD targets: 50% fT > MIC and 100% fT > MIC. [P-penicillin] varied notably between patients and was associated with age, weight, p-creatinine and estimated creatinine clearance (eCLcr). Additionally, an increase in [p-penicillin] during the treatment period showed strong correlation with age, a low eCLcr, a low weight and a low p-albumin. Of the 46 patients, 96% had [p-penicillin] that resulted in 50% fT > MIC, while 71% had [p-penicillin] resulting in 100% fT > MIC. The majority of patients not achieving the 100% fT > MIC target were infected with enterococci. Streptococci and staphylococci isolated from blood cultures were highly susceptible to penicillin G. Our results suggest that penicillin G 3 g q6 h is suitable to treat IE caused by streptococci and penicillin-susceptible staphylococci, but caution must be taken when the infection is caused by enterococci. When treating enterococci, therapeutic drug monitoring should be applied to optimize penicillin G dosing and exposure.

• Authors: Kristina Öbrink-Hansen, Henrik Wiggers, Bo Martin Bibby, Tore Forsingdal Hardlei, Kaare Jensen, Marianne Kragh Thomsen, Birgitte Brock, Eskild Petersen
• Journal: Basic & clinical pharmacology & toxicology (Basic Clin Pharmacol Toxicol) Vol. 120 Issue 2 Pg. 179-186 (Feb 2017) ISSN: 1742-7843 [Electronic] England
• PMID: 27565458 (Publication Type: Journal Article, Observational Study)
• Copyright: © 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

Chemical References

• Anti-Bacterial Agents
• Penicillin G

Topics

• Aged
• Anti-Bacterial Agents (administration & dosage, blood, pharmacokinetics)
• Drug Administration Schedule
• Drug Dosage Calculations
• Drug Monitoring (methods)
• Endocarditis, Bacterial (blood, drug therapy, microbiology)
• Female
• Humans
• Linear Models
• Male
• Microbial Sensitivity Tests
• Middle Aged
• Penicillin G (administration & dosage, blood, pharmacokinetics)
• Prospective Studies
• Recurrence
• Staphylococcal Infections (blood, drug therapy, microbiology)
• Streptococcal Infections (blood, drug therapy, microbiology)
• Treatment Outcome