Carbamazapine for Inherited Erythromelalgia Patients With NaV1.7 Mutations

Study Overview
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Brief Summary
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This research study is designed to investigate brain response using fMRI scan, and behavioral responses, to treatment with the drug carbamazepine (CBZ) in patients with the painful sodium channelopathy inherited Erythromelalgia (IEM). This study is designed to identify the central nervous system (CNS) regions that are activated during ongoing or evoked pain attacks, and the altered CNS response to CBZ treatment. This will advance our understanding of how IEM affects the brain. We also hope to validate a pharmacogenic approach to the study of IEM by use of an FDA approved drug. We hope, but cannot be sure, that subjects will directly benefit from this study.

Official Title
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Pilot Study on the Response of Inherited Erythromelalgia Patients With NaV1.7 Mutations to Carbamazepine: Clinical Imaging Study

Conditions
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Erythromelalgia

Intervention / Treatment
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* Drug: Carbamazepine
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: diagnosis/symptoms of EM specific NaV1.7 sodium channel mutations (including S241T) Exclusion Criteria: patients with no identified NaV1.7 mutation

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Carbamazepine<br>Administered in gradual doses from 200 mg twice a day increasing to no more than 800 mg twice a day if symptoms do not reduce. After 2 weeks of steady dose drug will be tapered down every 3 days. | Drug: Carbamazepine<br>* Day 1: Take 200 mg twice a day. Day 2: Take 200 mg twice a day. Day 3: Take 200 mg twice a day. Day 4: Take 200 mg twice a day. Day 5: Take 400 mg twice a day. Day 6: Take 400 mg twice a day. Day 7: Take 400 mg twice a day. Day 8: Take 400 mg twice a day. Day 9: Take 600 mg twice a day. Day 10: Take 600 mg twice a day. Day 11: Take 600 mg twice a day. Day 12: Take 600 mg twice a day. Day 13: Take 800 mg capsules twice a day. Day 14: Take 800 mg twice a day. Day 15: 800 mg twice a day. Day 16: Take 800 mg twice a day. Taper Down (After Visit 4 and 7) If maximal dose of 800 mg/day has been achieved, tapering down will take 9 days Taper down for 600 mg/day will take 6 days, and for 400 mg/day will take 3 days.<br>* Other names: Tegretol;|
| Placebo Comparator: Placebo<br>Administered in gradual doses from 200 mg twice a day increasing to no more than 800 mg twice a day if symptoms do not reduce to match dosing with carbamazepine. After 2 weeks of steady dose drug will be tapered down every 3 days. | Drug: Placebo<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Carbamazepine Affects Pain in Patients With S241T NaV1.7 IEM Mutation |  | 15 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Carbamazepine Affects Mean Duration of Pain Episode |  | 15 days |