Gentamicin contaminated with endotoxin

Analysis of histamine and sisomicin in gentamicin: Search for the causative agents of adverse effects

In 1998, the aminoglycoside antibiotic gentamicin sulfate caused several cases of deaths in the United States, after the switch from twice- to once-daily application. Endotoxins were discussed as the cause for the adverse effects and sisomicin was identified as the lead impurity; batches containing sisomicin were contaminated with more impurities and were responsible for the fatalities. In 2016, anaphylactic reactions in horses, and later in humans with one fatality, were observed after application of gentamicin sulfate contaminated with histamine. To determine whether histamine was responsible for the 1990s death cases as well, histamine was quantified by means of liquid chromatography-tandem mass spectrometry (LC-MS/MS) in 30 samples of gentamicin sulfate analyzed in previous studies. Furthermore, a relative quantification of sisomicin was performed to check for a correlation between histamine and the lead impurity. A maximum amount of 11.52 ppm histamine was detected, which is below the limit for anaphylactic reactions of 16 ppm, and no correlation of the two impurities was observed. However, the European Medicines Agency recommends a stricter limit with regard to the maximum single dose of gentamicin sulfate to reach a greater gap between the maximum histamine exposition of 4.3 µg and the quantity known to cause hypotension of 7 µg. The low amounts of histamine and the fact that there is no connection with the contamination with sisomicin showed that histamine was not the cause for the death cases in the United States in 1998, and endotoxins remain the most probable explanation.

Endotoxin-like reactions with intravenous gentamicin: results from pharmacovigilance tools under investigation

OBJECTIVE

To apply two data mining algorithms (DMAs) to Food and Drug Administration (FDA) Adverse Event Reporting System (AERS) reports that involved endotoxin-like reactions with intravenous gentamicin to determine whether a signal of disproportionate reporting of these events would have been generated concurrently with surveillance based on clinical observation.

DESIGN

Multi-item gamma-Poisson shrinker (MGPS) and proportional reporting ratios (PRRs) were used. Data used for data mining consisted of an extract of the FDA AERS database. Previously published details of clusters of endotoxin-like reactions to intravenous gentamicin were used to select adverse events for data mining.

RESULTS

The first signal of disproportionate reporting with any relevant event occurred in 1998, the year in which the outbreak was identified and evaluated by the Centers for Disease Control and Prevention and the FDA. In 1997, there were only 6 reports of rigors in the AERS; this jumped to 68 in 1998. In 1998, a signal was generated for endotoxic shock with PRRs but not with MGPS, based on one case.

CONCLUSIONS

The two DMAs generated signals concurrently with the influx of reports. It would have been difficult for safety reviewers to ignore an increase in rigors by traditional methods of safety surveillance; therefore, DMAs might not have had a great deal to offer in this instance. If data mining were considered as a second-line defense to diligent clinical observations under similar circumstances, simple disproportionality methods such as PRRs might be more useful than DMAs such as MGPS when commonly cited thresholds are used.

Pyrogenic reactions associated with single daily dosing of intravenous gentamicin

OBJECTIVE

To identify risk factors associated with an unexpected outbreak of pyrogenic reactions (PR) following intravenous gentamicin.

DESIGN

We conducted two cohort studies. PRs were defined as chills, rigors, or shaking within 3 hours after initiating the gentamicin infusion during the preepidemic (December 1, 1997-January 15, 1998) or epidemic (May 1-June 15, 1998) periods. We tested gentamicin vials for endotoxin using the limulus amebocyte lysate assay.

SETTING

Inpatient services of a large community hospital in Los Angeles, California.

RESULTS

During the epidemic period, 22 (15%) of 152 patients developed documented PRs following intravenous gentamicin. PRs were more likely among patients receiving single daily dosing (SDD) than multiple daily dosing gentamicin (20/73 [27%] vs. 2/79 [3%]; relative risk, 10.8; 95% confidence interval, 2.6 44.7). Laboratory analysis of gentamicin vials found endotoxin levels that were higher among Fujisawa-brand gentamicin (implicated brand) than gentamicin used after the outbreak terminated (non-implicated brand). Although endotoxin levels in the vials did not exceed US Pharmacopeia limits (1.7 endotoxin units/mg gentamicin), the use of SDD gentamicin may place patients at greater risk of receiving doses of endotoxin above the threshold for PRs in humans.

CONCLUSIONS

Reassessment of the acceptable amounts of endotoxin in gentamicin and other parenteral products should be considered when dosing intervals used in clinical practice change.