From the Guidelines
For a patient with a UTI who has a penicillin allergy, the most appropriate IV antibiotic option is ciprofloxacin 400mg IV every 12 hours, due to its excellent urinary tract penetration and broad coverage against common UTI pathogens, as recommended by the European Association of Urology guidelines 1. When considering treatment options, it's essential to take into account the severity of the infection, local resistance patterns, and patient factors such as renal function.
- Fluoroquinolones, like ciprofloxacin, are often preferred for their broad coverage and urinary tract penetration.
- Aminoglycosides, such as gentamicin, can be used in combination with other antibiotics for severe infections or suspected resistant organisms.
- Carbapenems, like meropenem, are also an option, but their use should be guided by local resistance patterns and patient factors. The choice of antibiotic should be guided by the most recent and highest quality evidence, which in this case is the European Association of Urology guidelines from 2024 1.
- It's also important to note that patients with severe penicillin allergies (anaphylaxis) should avoid beta-lactams entirely, including cephalosporins, due to potential cross-reactivity.
- Treatment duration typically ranges from 7-14 days, depending on severity, with consideration for oral step-down therapy once clinical improvement occurs, as recommended by the Infectious Diseases Society of America guidelines 1.
- Monitoring renal function is essential, particularly when using aminoglycosides, which require therapeutic drug monitoring to prevent toxicity, as highlighted in the Journal of Microbiology, Immunology and Infection guidelines 1.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION Dosage in Adult Patients AZACTAM may be administered intravenously or by intramuscular injection. WARNINGS Both animal and human data suggest that AZACTAM (aztreonam for injection, USP) is rarely cross-reactive with other beta-lactam antibiotics and weakly immunogenic. Treatment with aztreonam can result in hypersensitivity reactions in patients with or without prior exposure. While cross-reactivity of aztreonam with other beta-lactam antibiotics is rare, this drug should be administered with caution to any patient with a history of hypersensitivity to beta-lactams (eg, penicillins, cephalosporins, and/or carbapenems)
For a patient with a UTI and a penicillin allergy, the recommended IV antibiotic is aztreonam.
- The dosage for urinary tract infections is 500 mg or 1 g every 8 or 12 hours 2.
- Aztreonam is rarely cross-reactive with other beta-lactam antibiotics, but it should be administered with caution in patients with a history of hypersensitivity to beta-lactams 2.
From the Research
IV Antibiotics for UTI with Penicillin Allergy
- For patients with a penicillin allergy, alternative antibiotics are necessary to treat urinary tract infections (UTIs) 3.
- According to a study published in 2020, parenteral treatment options for UTIs due to ESBLs-producing Enterobacteriales include:
- Piperacillin-tazobactam (for ESBL-E coli only)
- Carbapenems (including meropenem/vaborbactam, imipenem/cilastatin-relebactam, and sulopenem)
- Ceftazidime-avibactam
- Ceftolozane-tazobactam
- Aminoglycosides (including plazomicin)
- Cefiderocol
- Fosfomycin
- Sitafloxacin
- Finafloxacin 4.
- Another study published in 2020 discusses the efficacy and safety of levofloxacin as a treatment for complicated UTIs and pyelonephritis, but notes that the emergence of fluoroquinolone resistance has limited its use 5.
- For patients with a penicillin allergy, clinicians should consider antimicrobial therapy with an antibiotic that does not cross-react with penicillins or beta-lactams 3.
- Studies comparing levofloxacin and ciprofloxacin for the treatment of UTIs found that the two drugs have similar efficacy and safety profiles 6, 7.