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

This study has been completed.
Ohio State University
Information provided by:
Office of Rare Diseases (ORD) Identifier:
First received: February 24, 2000
Last updated: June 23, 2005
Last verified: January 1998


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.

Condition Intervention Phase
Paralysis, Hyperkalemic Periodic Hypokalemic Periodic Paralysis Paramyotonia Congenita Drug: dichlorphenamide Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Masking: Double
Primary Purpose: Treatment

Resource links provided by NLM:

Further study details as provided by Office of Rare Diseases (ORD):

Estimated Enrollment: 64
Study Start Date: June 1992
Detailed Description:

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.


Ages Eligible for Study:   10 Years to 75 Years   (Child, Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No


--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


  • No renal failure
  • No nephrolithiasis


  • No heart disease
  • No cardiac arrhythmia

Pulmonary: No restrictive or obstructive lung disease


  • No active thyroid disease
  • No pregnant women
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Please refer to this study by its identifier: NCT00004802

Sponsors and Collaborators
National Center for Research Resources (NCRR)
Ohio State University
Study Chair: Jerry R. Mendell Ohio State University
  More Information Identifier: NCT00004802     History of Changes
Other Study ID Numbers: 199/11958
Study First Received: February 24, 2000
Last Updated: June 23, 2005

Keywords provided by Office of Rare Diseases (ORD):
neurologic and psychiatric disorders
periodic paralysis
rare disease

Additional relevant MeSH terms:
Myotonic Disorders
Hypokalemic Periodic Paralysis
Paralysis, Hyperkalemic Periodic
Neurologic Manifestations
Nervous System Diseases
Signs and Symptoms
Muscular Diseases
Musculoskeletal Diseases
Neuromuscular Diseases
Paralyses, Familial Periodic
Metal Metabolism, Inborn Errors
Metabolism, Inborn Errors
Genetic Diseases, Inborn
Metabolic Diseases
Carbonic Anhydrase Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action processed this record on September 21, 2017