Condition category
Urological and Genital Diseases
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting

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)

Trial website

Contact information



Primary contact

Prof Marion McMurdo


Contact details

Ageing and Health
Division of Medicine and Therapeutics
Ninewells Hospital and Medical School
United Kingdom

Additional identifiers

EudraCT number

2006-001313-15 number

Protocol/serial number


Study information

Scientific title

Cranberry or trimethoprim for the prevention of recurrent urinary tract infections? A randomized controlled trial in older women


Study hypothesis

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?

Ethics approval

Tayside Committee of Medical Research Ethics, 23/03/2006, ref: 06/S1402/23

Study design

Double-blind, randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting

Not specified

Trial type


Patient information sheet


Recurrent urinary tract infections


Trimethoprim 100 mg daily versus 500 mg cranberry product daily

Intervention type



Not Specified

Drug names


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

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Previous urological surgery, stone or anatomical abnormalities
2. Urinary catheter
3. Diabetes mellitus
4. Immunocompromised
5. Pyelonephritis
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

United Kingdom

Trial participating centre

Ageing and Health
United Kingdom

Sponsor information


University of Dundee (UK)

Sponsor details

Research and Innovation Services
University of Dundee
United Kingdom

Sponsor type




Funder type


Funder name

Moulton Charitable Foundation (UK)

Alternative name(s)

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)

Publication list

2008 results in

Publication citations

  1. Results

    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.

Additional files

Editorial Notes

21/02/2018: The following changes were made: 1. Scientific title, plain english summary and participant level data were added. 2. Primary and secondary outcome measures were updated. 3. Basic results Summary was added.