Antibiotics for urinary tract infections in ELDERLY patients

TMP/SMX is first-line for uncomplicated infections. Nitrofurantoin 100 mg BID for 5 days is a good option for uncomplicated UTIs....
Abdelwahab Ward, BS Pharm, PharmD

As a clinical pharmacist, you will be asked more, which antibiotics should be recommended for urinary tract infections in elderly patients? It depends on whether it's a "complicated" UTI or not. We know all UTIs in older MEN are considered complicated due to possible prostate involvement. UTIs in women can also be complicated due to a catheter, obstruction, immunosuppression, etc.

Antibiotic selection also depends on kidney function, side effects, and possible drug interactions. TMP/SMX is first-line for uncomplicated infections, if local resistance is 20%. Hospital pharmacists can get this number from their lab, and community pharmacists can get it from their hospital colleagues.

Recommend using TMP/SMX DS twice daily for 3 days, and half the dose if kidney function is impaired (CrCl 15 to 30 mL/min). Warn about possible hyperkalemia if TMP/SMX is combined with an ACEI, ARB, or potassium, or increased INR with warfarin. Nitrofurantoin 100 mg BID for 5 days is a good option for uncomplicated UTIs, IF renal function is okay. Avoid nitrofurantoin in patients with a CrCl < 60 mL/min, or for a complicated UTI. Quinolones are the best choice for complicated UTIs and kidney infections, or if patients can't take TMP/SMX or nitrofurantoin. Avoid moxifloxacin, it doesn't get into the urine. Recommend avoiding quinolones if local resistance is over 10%, and adjusting the dose for impaired renal function. Caution about possible adverse CNS effects, hyper- or hypo-glycemia, tendon rupture or increased INR in warfarin patients.

Beta-lactams (amoxicillin, etc) are usually less effective for UTIs. Suggest them only if other antibiotics aren't an option. Expect to see antibiotics given for 3 to 5 days for uncomplicated UTIs, 7 to 14 days for complicated UTIs, and 6 to 12 weeks for men with prostate involvement. Discourage treating patients with bacteria in their urine but NO symptoms. There's no benefit and it increases resistance.

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Abdelwahab Ward, BS Pharm, PharmD