Vaccinium tablets may be protective in older women
Cranberry extracts of 500 mg to 1,000 mg daily have been compared with antimicrobial prophylaxis in two randomized, double-blind, controlled trials. The trials demonstrated mixed benefits. Trimethoprim/sulfamethoxazole was associated with a lower rate of UTI in younger women, compared with cranberry extracts alone (P=.02), while cranberry extracts were slightly more effective than trimethoprim alone in older women.9,10 Cranberry tablets were not associated with bacterial resistance, were cheaper, and were viewed as a more natural option. The interventions were equally well tolerated.
Overall efficacy of cranberry tablets is unclear. Side effects, albeit mild, included gastrointestinal disturbances, vaginal complaints, and rash or urticaria. There was no significant difference in the rate of adverse effects between antimicrobial treatment and cranberry tablets.9
Cystopurin has not been studied
Cystopurin is an over-the-counter (OTC) tablet containing cranberry extract and potassium citrate that is taken three times daily (3 g/dose) for 2 days. Interestingly, although a proposed mechanism for the efficacy of vitamin C and cranberry juice has been a reduction of pH, potassium citrate is an alkalizing agent that is reported to relieve burning and reduce urinary urgency and frequency. No studies have assessed this medication in the treatment of a UTI or its symptoms.
Clinical recommendations
The evidence is mixed on the use of cranberry products to reduce recurrent UTI. However, given the limited side effects associated with these products, we offer cranberry tablets to patients who have recurrent UTIs who are interested in a more natural alternative.
We generally do not recommend cranberry juice because the added fluid volume tends to exacerbate frequency and urgency symptoms.
Lactobacilli suppositories may benefit
postmenopausal women
Lactobacilli are fastidious gram-positive rods and are usually the dominant component of the vaginal flora.11 They prevent colonization and infection by more virulent bacteria by competing for adhesion receptors and nutrients as well as producing antimicrobial substances such as hydrogen peroxide and lactic acid. A decrease in lactobacilli leaves the urinary tract susceptible to infectious organisms that may colonize the vaginal mucosa and increase the risk of recurrent UTI.12-14
A 2008 review of randomized, controlled trials of oral lactobacilli and UTI was inconclusive, due to inconsistent dosing strategies and small sample sizes.15 A 2011 randomized, double-blind, placebo-controlled phase 2 trial of Lactin-V, a lactobacilli vaginal suppository, found that it reduced the rate of recurrent UTI. Lactin-V contains a hydrogen-peroxide–producing Lactobacillus crispatus developed as a probiotic that was determined to be safe and tolerable as a vaginal suppository in a phase 1 trial.16 The phase 2 trial enrolled 100 young premenopausal women with a history of recurrent UTI who took either Lactin-V or placebo daily for 5 days, then weekly for 10 weeks. Women in the Lactin-V group who had high levels of L. crispatus colonization experienced a significant reduction in the rate of UTI (15% vs 27% in the placebo group), but the effect did not reach statistical significance.14
Little difference in adverse effects
Adverse effects were reported among 56% of patients who received Lactin-V versus 50% of those given placebo. The most common of these were vaginal discharge, itching, and moderate abdominal discomfort.14 Although lactobacillus can potentially promote UTI, this phenomenon is rare.11
Regrettably, Lactin-V is not currently available in the United States. However, there are other lactobacilli vaginal suppositories on the market ( TABLE ). Given the low risk associated with their use, they should be considered as an alternative for patients who cannot or will not use estrogen.
Clinical recommendations
Probiotics such as lactobacilli are categorized as “dietary supplements”; as such, they are not regulated by the US Food and Drug Administration. We recommend the use of lactobacilli suppositories in postmenopausal women who have a contraindication to (or prefer to avoid) vaginal estrogen.
Skip blueberry products for now
Like cranberries, blueberries belong to the Vaccinium species and are thought to interfere with bacterial adhesion to the walls of the bladder. One in vitro trial suggests that blueberries also have antiproliferation effects, although no clinical studies have been performed to date to further investigate safety or efficacy.4 Consequently, we do not recommend use of these products.
Methenamine salts may benefit some populations
These anti-infective agents, including methenamine hippurate and methenamine mandelate, often are used to prevent UTI. They are found in combination OTC medications, such as Prosed DS and Urelle. Methenamine salts are bacteriostatic to all urinary tract pathogens due to their production of formaldehyde.3,16
Although methenamine produces varying concentrations of formaldehyde, depending on the acidity of the urine, there is no evidence that acidified urine enhances methenamine’s effects.16