Phase III Randomized, Double-Blind, Placebo-Controlled Study of Dichlorphenamide for Periodic Paralyses and Associated Sodium Channel Disorders

Study Overview
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Brief Summary
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OBJECTIVES: I. Assess the efficacy of dichlorphenamide in the treatment of episodic weakness attacks in patients with hyperkalemic periodic paralysis, paramyotonia congenita with periodic paralysis, and hypokalemic periodic paralysis.

Detailed Description
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PROTOCOL OUTLINE: This is a randomized, double-blind study. Patients are stratified by participating institution and diagnosis. The weekly attack rate is determined during an 8-week assessment prior to therapy initiation and at crossover. Patients are randomly assigned to oral dichlorphenamide (DCP) or placebo for 9 weeks and then cross to the alternate treatment. Patients on DCP at baseline continue on the same dose; those on acetazolamide (ACZ) at baseline receive a DCP dose equivalent to one fifth of the ACZ dose.

Conditions
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Paralysis, Hyperkalemic Periodic, Hypokalemic Periodic Paralysis, Paramyotonia Congenita

Intervention / Treatment
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* Drug: dichlorphenamide


Participation Criteria
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Eligibility Criteria
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PROTOCOL ENTRY CRITERIA: --Disease Characteristics-- Hypokalemic periodic paralysis Typical clinical profile Normal serum thyroxine Hypokalemia during spontaneous or glucose-induced paralytic attack in subject or affected family member Periodic paralysis associated with sodium channel 17q alpha-subunit, e.g.: Hyperkalemic periodic paralysis with or without myotonia Paramyotonia congenita with periodic paralysis Distinct, regular episodes of weakness at least once a week and no more than 3 times a day No history of worsening symptoms with carbonic anhydrase inhibitor No history of life-threatening weakness episodes prior to treatment No atypical periodic paralysis without demonstrable 17q alpha-subunit defect --Prior/Concurrent Therapy-- No requirement for the following agents, unless for periodic paralysis: Diuretics Antiepileptics Antiarrhythmics Magnesium supplements Steroids Calcium supplements Beta-blockers Potassium supplements Calcium channel blockers --Patient Characteristics-- Hepatic: No hepatic disease Renal: No renal failure No nephrolithiasis Cardiovascular: No heart disease No cardiac arrhythmia Pulmonary: No restrictive or obstructive lung disease Other: No active thyroid disease No pregnant women

Ages Eligible for Study
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Minimum Age: 10 Years
Maximum Age: 75 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
Masking: Double


Arms and Interventions

| Intervention/Treatment |
| --- |
|Drug: dichlorphenamide|nan|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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neurologic and psychiatric disorders, periodic paralysis, rare disease