Safety and Efficacy Study of Ethosuximide for the Treatment of Complex Regional Pain Syndrome (CRPS)
![]() |
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT00689585 |
Recruitment Status
:
Terminated
(Recruitment difficult and enrolment low: decision was made to stop the study.)
First Posted
: June 3, 2008
Last Update Posted
: May 13, 2011
|
- Study Details
- Tabular View
- No Results Posted
- Disclaimer
- How to Read a Study Record
Condition or disease | Intervention/treatment | Phase |
---|---|---|
Complex Regional Pain Syndromes | Drug: Placebo Drug: Ethosuximide | Phase 2 |
This is a single centre, parallel-group, double-blind, randomized, placebo-controlled pilot clinical trial for adults suffering from complex regional pain syndrome (CRPS).
Twelve (12) subjects diagnosed with CRPS will be enrolled and randomized to receive orally, either ethosuximide or placebo. If the maximum trial medication dosage (1500mg) is reached, the subject will be in the study for a maximum of 10 weeks from screening (Clinic Visit 1) to the end of the drug cessation period. The minimum period a subject could complete the study would be 4 weeks presuming they were not previously on any disallowed drugs and only found the 500mg dose tolerable.
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 4 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Primary Purpose: | Treatment |
Official Title: | A Single Centre. Parallel-Group, Double-Blinded, Randomized, Placebo-Controlled Pilot Clinical Trial on Ethosuximide for the Treatment of Complex Regional Pain Syndrome (CRPS) |
Study Start Date : | September 2008 |
Actual Primary Completion Date : | July 2010 |
Actual Study Completion Date : | July 2010 |

Arm | Intervention/treatment |
---|---|
Placebo Comparator: 1 |
Drug: Placebo
250mg matching placebo capsules
|
Experimental: 2 |
Drug: Ethosuximide
500-1500mg/day over a 1-5 week dose titration period until maximal tolerated dose (MTD) attained, followed by 1 week MTD plateau period.
Other Name: Zarontin
|
- Maximum tolerated dose (500mg-1500mg per day) and Safety profile [ Time Frame: up to 10 weeks ]Primary outcomes will consist of the dose attained during the study and the safety (adverse event) profile. Maximum timeframe on study drug is 6 weeks. Adverse events will be collected up to one month after the trial period ends.
- Pain Intensity Scores on the Visual Analogue Scale (VAS) [ Time Frame: up to 7 weeks ]Pain Intensity captured on Day 1 (First study visit post-disallowed drug cessation period) and 7 days after maximal-tolerated dose attained (Final Study Visit)
- Pain Intensity Scores on the Numerical Rating Scale (NRS) [ Time Frame: up to 5 weeks ]Pain Intensity using the Numerical Rating Scale will be captured by telephone every week during dose titration period (Days 3 and 6).
- Neuropathic Pain Symptom Inventory (NPSI) [ Time Frame: up to 7 weeks ]Day 1 (First study visit post-disallowed drug cessation period) and 7 days after maximal-tolerated dose attained (Final Study Visit)
- Short Form 12v2 (SF-12v2) [ Time Frame: up to 7 weeks ]Quality of Life measured on Day 1 (First study visit post-disallowed drug cessation period) and 7 days after maximal-tolerated dose attained (Final Study Visit)
- Short Form McGill Pain Questionnaire (SF-MPQ) [ Time Frame: up to 7 weeks ]Day 1 (First study visit post-disallowed drug cessation period) and 7 days after maximal-tolerated dose attained (Final Study Visit)

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 18 Years and older (Adult, Senior) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Male or female, age ≥18 years old;
- Diagnosis of Complex Regional Pain Syndrome (CRPS) using International Association for the Study of Pain criteria >6 months;
- Normal liver function (AST level <3x normal level);
- Normal kidney function (serum creatinine <133µmol/L);
- Full blood count, haematocrit >38%;
- Willing and able to give informed consent and of completing study questionnaires;
- Stable (no change in past two months) but suboptimal pain pharmacotherapy (i.e. additional pain control felt by patient and physician to be necessary);
- Able to attend research centre according to the visit schedule;
- Women of child-bearing potential must be using a reliable form of contraception i.e. oral contraceptives, a barrier method (condom or diaphragm), intra-uterine device or abstinence.
Exclusion Criteria:
- Optimal response to opioids, antidepressants, anticonvulsants or anti- inflammatory medications;
- Any history or indication of kidney or liver disease;
- Any history of alcohol abuse;
- Presence of diabetes;
- Subjects taking other anti-epileptic drugs, including gabapentin, pregabalin, topiramate, phenytoin, carbamazepine, and oxcarbazepine;
- Pregnancy (a serum bHCG pregnancy test will be performed as part of the initial blood panel);
- Known or suspected allergy to succinimides, ethosuximide, methsuximide (Celontin®), phensuximide;
- Any history of mental illness or disorder, which in the investigators opinion, interferes with the subjects ability to accurately report treatment response;
- Participation in other clinical trial in the 30 days prior to enrolment.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00689585
Canada, Quebec | |
McGill University Health Centre | |
Montreal, Quebec, Canada, H3G 1A4 |
Principal Investigator: | Mark A Ware, MD | McGill University Health Center |
Responsible Party: | Mark A. Ware, Prinicipal Investigator, McGill University Health Centre - Pain Centre |
ClinicalTrials.gov Identifier: | NCT00689585 History of Changes |
Other Study ID Numbers: |
GEN#07-062 |
First Posted: | June 3, 2008 Key Record Dates |
Last Update Posted: | May 13, 2011 |
Last Verified: | May 2011 |
Keywords provided by McGill University Health Center:
Complex Regional Pain Syndrome Reflex Sympathetic Dystrophy RSD Chronic Pain |
Ethosuximide Zarontin Anticonvulsant |
Additional relevant MeSH terms:
Syndrome Complex Regional Pain Syndromes Reflex Sympathetic Dystrophy Somatoform Disorders Disease Pathologic Processes Mental Disorders |
Autonomic Nervous System Diseases Nervous System Diseases Peripheral Nervous System Diseases Neuromuscular Diseases Ethosuximide Anticonvulsants |