Anaphylaxis induced by fosfomycin

Adverse Events Associated with Fosfomycin Use: Review of the Literature and Analyses of the FDA Adverse Event Reporting System Database

Introduction

The growing problem of antibacterial resistance resulted in an increased interest in fosfomycin, especially its parenteral formulation. We reviewed fosfomycin safety profile using the Food and Drug Administration Adverse Event (AE) Reporting System (FAERS) and published literature.

Methods

We conducted a FAERS search and disproportionality analysis of all fosfomycin-associated AEs. We also conducted a FAERS search for AEs implicating fosfomycin as the primary suspect and a search of reports of fosfomycin-associated bone marrow toxicity. We then review the literature for publications reporting AEs associated with fosfomycin by conducting PubMed searches.

Results

The disproportionality analysis of all FAERS reports of fosfomycin-associated AEs produced a higher than expected frequency of agranulocytosis, liver injury, severe skin reactions, and pseudomembranous colitis. Subsequent search for AEs where fosfomycin was the primary suspect and the literature review did not suggest a higher association of fosfomycin with these AEs. The search of bone marrow toxicity reports did not demonstrate an association between aplastic anemia and fosfomycin. The literature review selected 23 trials of parenteral administration of fosfomycin in 1242 patients including 8 comparative and 15 non-comparative trials. For oral fosfomycin, only prospective comparative trials (n = 28) in 2743 patients were included. The most frequent AEs associated with parenteral fosfomycin included rash, peripheral phlebitis, hypokalemia, and gastrointestinal disorders. Serious AEs such as aplastic anemia, anaphylaxis, and liver toxicities were reported infrequently. Gastrointestinal disorders were the most common AEs associated with oral fosfomycin.

Conclusion

The identified AEs were consistent with the safety profile of fosfomycin. No new safety signals related to either parenteral or oral fosfomycin were identified.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-015-0092-8) contains supplementary material, which is available to authorized users.

The revival of fosfomycin

Fosfomycin, originally named phosphonomycin, was discovered in Spain in 1969. There are three forms of fosfomycin: fosfomycin tromethamine (a soluble salt) and fosfomycin calcium for oral use, and fosfomycin disodium for intravenous use. Fosfomycin is a bactericidal antibiotic that interferes with cell wall synthesis in both Gram-positive and Gram-negative bacteria by inhibiting the initial step involving phosphoenolpyruvate synthetase. It has a broad spectrum of activity against a wide range of Gram-positive and Gram-negative bacteria. It is highly active against Gram-positive pathogens such as Staphylococcus aureus and Enterococcus, and against Gram-negative bacteria such as Pseudomonas aeruginosa and Klebsiella pneumoniae. Its unique mechanism of action may provide a synergistic effect to other classes of antibiotics including beta-lactams, aminoglycosides, and fluoroquinolones. Oral fosfomycin is mainly used in the treatment of urinary tract infections, particularly those caused by Escherichia coli and Enterococcus faecalis. Intravenous fosfomycin has been administered in combination with other antibiotics for the treatment of nosocomial infections due to multidrug-resistant (MDR) Gram-positive and Gram-negative bacteria. Fosfomycin has good distribution into tissues, achieving clinically relevant concentrations in serum, kidneys, bladder wall, prostate, lungs, inflamed tissues, bone, cerebrospinal fluid, abscess fluid, and heart valves. Fosfomycin is well tolerated, with a low incidence of adverse events. Further randomized controlled trials are needed in order to evaluate the efficacy of intravenous fosfomycin for the management of nosocomial infections due to MDR pathogens.