Plain English Summary
Background and study aims
Recent evidence shows that substances found in cranberries might help in preventing recurrent urinary infections. Recurrent urinary infections are common and troubling in older women. The usual treatment is either repeated doses of antibiotic at the time of infection or continuous low doses of antibiotic for prolonged periods of time. Unfortunately antibiotics have unwanted effects and may harm the good bacteria of your gut and lead to the development of antibiotic resistant infections.
The aim of this study is to find out whether cranberry products will reduce the occurrence of urinary infections when compared to the usual treatment with low doses of trimethoprim (an antibiotic).
Who can participate?
Adult women aged 45 years or over who have had two UTIS or episodes of cystitis in the previous 12 months
What does the study involve?
The study lasts for 6 months. At the start, participants provide a sample of urine. They are randomly allocated to one of two groups. All participants take one capsule of study medication each day, which will contain either 100mg of trimethoprim, or 500mg of cranberry extract depending on their group.
During the 6 months in the study, participants are asked to report any urine infections you have, any courses of antibiotics you take, and any side effects that you experience. At the end of the 6 months, any spare study capsules that are left will be taken back and counted.
What are the possible benefits and risks of participating?
It is possible that participants will have fewer urine infections as a result of taking one of the study medications, but we do not know which one will prevent more infections.
There are no known side effects of cranberry product. Trimethoprim, a commonly used antibiotic, is the recommended treatment for urinary infections, but it can rarely cause side effects like upset stomach and rashes.
Where is the study run from?
Ninewells Hospital Dundee (UK)
When is the study starting and how long is it expected to run for?
September 2006 to August 2008
Who is funding the study?
Moulton Charitable Foundation (UK)
Who is the main contact?
Prof Marion McMurdo (Scientific)
Cranberry or trimethoprim for the prevention of recurrent urinary tract infections? A randomized controlled trial in older women
1. What is the relative effectiveness of low dose trimethoprim compared to cranberry product in the prevention of urinary tract infections in older women with recurrent infections?
2. What is the acceptability of and adherence to both preventative treatments?
Tayside Committee of Medical Research Ethics, 23/03/2006, ref: 06/S1402/23
Double-blind, randomised controlled trial
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Recurrent urinary tract infections
Trimethoprim 100 mg daily versus 500 mg cranberry product daily
Primary outcome measure
Current primary outcome measure (as of 21/02/2018:)
First recurrence of symptomatic urinary tract infection self reported by patient during 6 month study
Previous primary outcome measure:
First recurrence of symptomatic urinary tract infection
Secondary outcome measures
Current secondary outcome measures (as of 21/02/2018):
Acceptability and adherence, measured by number of capsules left at the end of the 6 month study
Previous secondary outcome measure:
Acceptability and adherence
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
Community dwelling women aged 45 years or over with at least two antibiotic-treated urinary tract infections or episodes of cystitis in the previous 12 months
Target number of participants
Participant exclusion criteria
1. Previous urological surgery, stone or anatomical abnormalities
2. Urinary catheter
3. Diabetes mellitus
6. Severe renal impairment
7. Blood dyscrasia
8. Symptomatic urinary tract infection (UTI) at baseline
9. Cognitive impairment precluding informed consent
10. Resident in institutional care
11. On longterm antibiotics
12. On warfarin therapy
13. Regular cranberry consumers
14. Unwilling to participate
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Ageing and Health
Moulton Charitable Foundation (UK)
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
IPD sharing statement: Individual participant data are not available for sharing
Intention to publish date
Participant level data
Not expected to be available
Basic results (scientific)
2008 results in http://www.ncbi.nlm.nih.gov/pubmed/19042940
McMurdo ME, Argo I, Phillips G, Daly F, Davey P, Cranberry or trimethoprim for the prevention of recurrent urinary tract infections? A randomized controlled trial in older women., J. Antimicrob. Chemother., 2009, 63, 2, 389-395, doi: 10.1093/jac/dkn489.
- ISRCTN80031108_BasicResults_21Feb18.pdf Uploaded: 21/02/2018