From the Guidelines
For a patient with a urinary tract infection (UTI) who is allergic to Bactrim, ciprofloxacin, nitrofurantoin, cefdinir, and cephalexin, I strongly recommend using fosfomycin (3 g in a single dose) as the primary treatment option, due to its minimal resistance and propensity for collateral damage, as supported by the Infectious Diseases Society of America guidelines 1. When considering treatment options for this patient, it's essential to weigh the benefits and risks of each antibiotic, taking into account the patient's allergy profile and the potential for collateral damage.
- Fosfomycin is a suitable choice because it has a unique mechanism of action, inhibiting bacterial cell wall synthesis, which reduces the likelihood of cross-reactivity with the patient's known allergens.
- The dosage of fosfomycin is typically 3 grams as a single-dose powder packet dissolved in water, which is usually sufficient for uncomplicated UTIs.
- Alternatively, pivmecillinam (400 mg bid for 3–7 days) could be considered, as it is also recommended for regions where it is available, due to minimal resistance and propensity for collateral damage, although it may have inferior efficacy compared to other available therapies 1.
- It's crucial to obtain a urine culture to confirm the specific bacterial sensitivity, especially with this extensive allergy profile, to ensure the chosen antibiotic is effective against the infecting strain.
- Monitoring for improvement of symptoms within 48-72 hours is vital, and patients should complete the full course of any prescribed antibiotic to minimize the risk of treatment failure and development of antibiotic resistance.
From the Research
UTI Treatment Options for Patients with Allergies
- The patient is allergic to Bactrim, Ciprofloxacin, Nitrofurantoin, Cefdinir, and Cefalaxin, which limits the treatment options for UTI 2.
- Alternative treatment options for UTIs due to ESBL-E coli include amoxicillin-clavulanate, finafloxacin, and sitafloxacin, while options for ESBL-Klebsiella pneumoniae include pivmecillinam, fosfomycin, finafloxacin, and sitafloxacin 2.
- Parenteral treatment options for UTIs due to ESBL-producing Enterobacteriales include piperacillin-tazobactam, carbapenems, ceftazidime-avibactam, and aminoglycosides including plazomicin 2.
- Cephalexin and cefadroxil are first-generation oral cephalosporins that have been considered second-line treatment options for uncomplicated lower urinary tract infections (uLUTIs) 3.
- Cephalexin may be a practical choice for many clinicians due to its convenient administration and reliable antimicrobial susceptibility test interpretative criteria 3.
Considerations for Specific Antibiotics
- Trimethoprim-sulfamethoxazole is a effective combination agent in vitro, but its use may be limited due to high rates of resistance in some communities 2, 4, 5.
- Trimethoprim use for UTI is associated with an increased risk of acute kidney injury and hyperkalaemia, particularly in older patients taking renin-angiotensin system blockers and potassium-sparing diuretics 6.
- Amoxicillin-clavulanate may be a suitable alternative to trimethoprim for UTI treatment, with a lower risk of acute kidney injury and hyperkalaemia 6.
Additional Treatment Options
- Fosfomycin tromethamine is a recommended first-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females 2.
- Pivmecillinam is another recommended first-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females 2.