Cotrimoxazole Linked to Higher Adverse Event Risk in Older Adults With UTIs: Study
France: Older adults treated with cotrimoxazole for urinary tract infections (UTIs) experienced nearly twice the risk of adverse events compared with those receiving fluoroquinolones. Cotrimoxazole users also had higher rates of treatment discontinuation due to side effects, indicating lower tolerability in this age group.
Urinary tract infections in older men represent a frequent and clinically challenging condition, often requiring antibiotic therapy with agents such as fluoroquinolones or cotrimoxazole. However, safety data in frail elderly populations remain limited, despite guideline recommendations supporting both options for urinary tract infections in men.
A new multicentre retrospective study published in Open Forum Infectious Diseases by P. Caraux-Paz and colleagues evaluated the safety profiles of these antibiotics in patients aged 75 years and older hospitalized for urinary tract infections. The study included eight hospitals and focused specifically on adverse events occurring during hospital stay.
The study revealed the following findings:
- A total of 228 patients with a median age of 85 years were included in the analysis.
- Of these, 131 patients received fluoroquinolones, while 97 were treated with cotrimoxazole.
- Baseline clinical characteristics were broadly similar between the two treatment groups, enabling a valid comparison of safety outcomes.
- Adverse events were significantly more frequent in the cotrimoxazole group (48.5%) compared with the fluoroquinolone group (29.7%).
- After adjustment for confounders, cotrimoxazole was associated with nearly a twofold higher risk of adverse events.
- Treatment discontinuation due to side effects was more common with cotrimoxazole (11.3%) than with fluoroquinolones (2.3%).
- Acute kidney injury occurred more frequently in patients receiving cotrimoxazole (29.4%) compared to those receiving fluoroquinolones (7.2%).
- Metabolic disturbances were also higher in the cotrimoxazole group (18.6% vs 7.6%).
- No significant differences were observed between the two groups in other adverse events or overall mortality.
The findings suggest that while both antibiotics are used in clinical practice for urinary tract infections in older men, fluoroquinolones may be associated with a more favourable safety profile in this high-risk population. The authors note that the increased susceptibility of elderly patients to drug-related toxicity likely contributes to the observed differences.
Despite the retrospective design of the study, the results provide important real-world evidence regarding antibiotic safety in frail older adults. The researchers emphasise that prospective studies are needed to confirm these findings and to better inform antibiotic selection in this growing patient population.
Overall, the study highlights the importance of careful antibiotic choice in elderly patients with urinary tract infections, balancing efficacy with the risk of treatment-related harm.
Reference:
Gouraud, C., Putot, A., Fraisse, T., Bermejo, M., Viala, B., Golstein, C., Lemarie, N., Roubaud Baudron, C., & Caraux-Paz, P. Safety of fluoroquinolones and cotrimoxazole in urinary tract infections in older males. Open Forum Infectious Diseases. https://doi.org/10.1093/ofid/ofag271
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