Do cranberries prevent recurrent urinary tract infections? According to recent data, no. Although earlier studies suggested a benefit, the most recent Cochrane review of 24 studies and 4500 patients did not show that cranberry products decrease the incidence of recurrent UTIs. There are several theories as to how cranberries might work. Some researchers believe that cranberries contain antioxidants which alter harmful bacteria so that they are unable to stick to the bladder wall. Others suggest a substance in cranberries creates a slippery coating on the bladder which makes it hard for bacteria to adhere. Regardless of the theories, data does not support efficacy.

Jepson RG, et al. Cranberries for preventing urinary tract

infections. Cochrane Database Syst Rev. 2012 Oct 17;10:CD001321. doi:

10.1002/14651858.CD001321.pub5. PMID: 23076891.

Continuous antibiotic prophylaxis works for preventing UTIs, but studies are not clear on the preferred antibiotic regimen and dosing strategies. No one agent has proven to be better than another; several have been studied, including clotrimazole, nitrofurantoin, cephalexin, and quinolones. Once daily dosing seems to be better than post-coital, although post-coital may be the good choice for those who have a clear association with intercourse. The evidence supports a duration of therapy up to one year.

When should daily antibiotic prophylaxis be considered? It’s unclear. Some suggest initiating continuous antibiotics when a patient has more than two UTIs in a year, but others place the cut-off at greater than three to six UTIs annually.

What about the “pill in the pocket” approach, where the patient has a standing prescription for an antibiotic to take when symptoms recur? With increasing awareness and concern about antibiotic resistance, there are fewer supporters for this tactic. Dr. James gives patients a prescription for empiric antibiotics for the first two UTIs in a year, but for additional episodes she requires a more thorough evaluation with urine culture and sensitivities to confirm the diagnosis.

The Society of Obstetricians and Gynecologists of Canada published a guideline in 2010 with the following recommendations for patients with recurrent UTIs [link to SOGC guidelines]:

Verify the diagnosis

Do a urine culture and sensitivity.



Exclude causes of vaginitis, such as chlamydia, herpes, and gonorrhea.

Screen for contributing factors

Perform a physical exam to evaluate for anatomical conditions which predispose to UTIs, such as cystocele, uterine prolapse, and atrophic vaginitis.



Consider a post-void residual to rule out urinary retention.



Test for diabetes.

Dr. James tailors her exam and work-up depending on the patient’s age and comorbidity. She is likely to do all of the above tests only on an older patient with recurrent UTIs.

Which patients require referral to a urologist or gynecologist? This is advisable for those with any of the following conditions:

Large cystoceles or uterine prolapse

A urine culture which grows an unusual pathogen which may be associated with a structural problem (e.g. proteus, klebsiella, pseudomonas)

Persistent hematuria, requiring cystoscopy

History of nephrolithiasis

What factors might place patients at higher risk for recurrent UTIs?