Initial trial of 6-month prophylaxis
Most authorities advocate a 6-month trial of prophylaxis, with the dose administered at night, after which the regimen is discontinued and the patient observed for further infection. The rationale for the 6-month prophylaxis period is empiric, based on observations that UTIs seem to cluster in some women.
- before any long term prophylaxis regimen is initiated, eradication of a previous uropathogen should be confirmed by a negative urine culture 1-2 weeks after treatment
- trimethoprim 100 mg once daily OR Nitrofurantoin 50-100 mg once daily may be used (4)
- either should be tried for 6 months then stopped
- N.B. Nitrofurantoin is contraindicated if eGFR <60ml/min (due to the drug being ineffective in poor renal function as it does not concentrate in sufficient quantities in the urine)
- patients prescribed long term nitrofurantoin should be monitored closely for signs of chronic pulmonary reactions and hepatitis for full details of contraindications and side effects see the manufacturer's Summary of Product Characteristics (SPC)
- 60% of women will develop symptoms within 3-4 months of discontinuation and so will require long term prophylaxis (4)
- it appears that most women revert back to the earlier pattern of recurrent infections once prophylaxis is stopped unless other factors, such as sexual activity or diaphragm-spermicide use, are modified. Some authorities advocate a longer period of prophylaxis -2 or more years - in women who continue to have symptomatic infections
Antibiotics used in a continuous antibiotic prophylaxis regime for an adult include (2,3):
- trimethoprim 100mg nocte
- nitrofurantoin 50 mg or 100 mg nocte
Other agents used for UTI prophylaxis include:
- cephalexin 250 mg nocte
- ciprofloxacin 125 mg nocte
- norfloxacin 200 mg nocte
- ofloxacin 100 mg nocte
Antibiotics used in a prophylactic regime are generally alternated every 3-6 months
*Consult local laboratory guidance for local antibiotic policies
Notes:
- "any woman who has recurrent, symptomatic and unexplained urinary infections should be referred for investigation using radiological imaging such as ultrasonography, to exclude anatomical abnormalities." (3)
- consider non-urgent referral for bladder cancer in people aged 60 and over with recurrent or persistent unexplained urinary tract infection (5)
Reference: