The action of gabapentin for the management of chronic pelvic pain in women (GaPP)

ISRCTN	ISRCTN70960777
DOI	https://doi.org/10.1186/ISRCTN70960777
Protocol serial number	Version 1
Sponsor	University of Edinburgh (UK)
Funder	Chief Scientist Office (CSO) (UK)

Submission date: 16/12/2011
Registration date: 28/02/2012
Last edited: 02/07/2020

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Musculoskeletal Diseases

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Plain English summary of protocol

Background and study aims
Chronic pelvic pain (CPP) affects more than 1 million women in the UK. Annual healthcare costs are estimated at more than £150 million. Proven treatments for CPP are limited and are often unsatisfactory. Gabapentin is increasingly prescribed due to reports of effectiveness in other chronic pain conditions but there is not enough data supporting its use in CPP specifically. This study aims to measure the effectiveness of gabapentin in the treatment of women with chronic pelvic pain with no known cause.

Who can participate?
Women aged between 18 and 50 who have experienced pelvic pain for more than 6 months.

What does the study involve?
Participants will be randomly allocated to receive either gabapentin or a dummy pill (placebo) daily for 6 months.

What are the possible benefits and risks of participating?
Participants may experience a reduction in their pelvic pain.

Where is the study run from?
Royal Infirmary of Edinburgh (UK)

When is the study starting and how long is it expected to run for?
February 2012 to November 2013

Who is funding the study?
Chief Scientist Office (CSO) (UK)

Who is the main contact?
Dr Andrew Horne
Royal Infirmary of Edinburgh (UK)

Contact information

Dr Andrew Horne
Scientific

Medical Research Council Centre for Reproductive Health
Queen's Medical Research Institute
Royal Infirmary of Edinburgh
47 Little France Crescent
Edinburgh
EH16 4SA
United Kingdom

Study information

Primary study design	Interventional
Study design	Two-arm parallel group pilot trial
Secondary study design	Randomised controlled trial
Study type	Participant information sheet
Scientific title	A pilot randomised controlled trial of the efficacy and mechanism of action of Gabapentin for the management of chronic Pelvic Pain in women (GaPP)
Study acronym	GaPP
Study objectives	The aim of this study is to assess recruitment and retention rates and to obtain data to refine the research methodology for a full randomised controlled trial investigating the efficacy and mechanism of action of gabapentin for the management of chronic pelvic pain in women.
Ethics approval(s)	Scotland A Research Ethics Committee, 26/01/2011, ref: 12/SS/0005
Health condition(s) or problem(s) studied	Chronic pelvic pain
Intervention	Gabapentin versus placebo. 300mg dose increasing in weekly increments to a maximum dose of 2700 mg if pain has not been reduced by 50% each week. Daily administration (TID) and by oral capsule, treatment given for 6 months.
Intervention type	Drug
Phase	Not Applicable
Drug / device / biological / vaccine name(s)	Gabapentin
Primary outcome measure(s)	Determine whether it is possible to achieve acceptable recruitment and retention rates in two centres (NHS Lothian and NHS Grampian)
Key secondary outcome measure(s)	1. To determine the effectiveness and acceptability to patients of the proposed methods of recruitment, randomisation, drug treatments, use of brain functional magnetic resonance imaging (fMRI) and follow-up 2. To determine whether fMRI of the brain is a sensitive approach to determine the mechanism of action of gabapentin in the management of CPP 3. To determine whether gabapentin is likely to be cost effective given the current level of evidence and uncertainty, and to ascertain what further evidence is needed for the evaluation of gabapentin
Completion date	01/11/2013

Eligibility

Participant type(s)	Patient
Age group	Adult
Lower age limit	18 Years
Upper age limit	50 Years
Sex	Female
Target sample size at registration	60
Key inclusion criteria	1. Women aged between 18-50 2. Consented to a routine diagnostic laparoscopy 3. Pelvic pain of > 6 months 4. Pain located within the true pelvis or between and below anterior iliac crests, associated functional disability 5. No obvious pelvic pathology
Key exclusion criteria	1. Known pelvic pathology e.g. endometriosis, cyst 2. Undergoing major surgery eg hysterectomy 3. Estimated Glomerular Filtration Rate (eGFR) >60
Date of first enrolment	01/02/2012
Date of final enrolment	01/11/2013

Locations

Countries of recruitment

United Kingdom
Scotland

Study participating centre

Royal Infirmary of Edinburgh

Edinburgh
EH16 4SA
United Kingdom

Results and Publications

Individual participant data (IPD) Intention to share	No
IPD sharing plan summary	Not provided at time of registration
IPD sharing plan

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Results article	results	12/04/2016		Yes	No
Results article	results	27/06/2019	02/07/2020	Yes	No
Protocol article	protocol	08/06/2012		Yes	No
HRA research summary			28/06/2023	No	No
Participant information sheet	Participant information sheet	11/11/2025	11/11/2025	No	Yes

Editorial Notes

02/07/2020: Publication reference added.
30/08/2016: Publication reference added.
08/08/2016: Publication reference added.