Hyper- and Hypokalemic Periodic Paralysis Study (HYP-HOP)

This study has been completed.
Information provided by (Responsible Party):
Robert Griggs, MD, University of Rochester
ClinicalTrials.gov Identifier:
First received: June 27, 2007
Last updated: February 17, 2014
Last verified: February 2014

June 27, 2007
February 17, 2014
June 2007
April 2013   (final data collection date for primary outcome measure)
The number of attacks/week over the last 8 weeks of the initial 9-week study phase. [ Time Frame: 8 weeks ] [ Designated as safety issue: Yes ]
The number of attacks/week over the last 8 weeks.
Complete list of historical versions of study NCT00494507 on ClinicalTrials.gov Archive Site
Efficacy: severity-weighted attack rate; muscle strength and mass measures; changes in health-related quality-of-life; intolerable increase in attack frequency or severity necessitating withdrawal from the 9-week phase (HOP trial only). [ Time Frame: 8 to 61 weeks ] [ Designated as safety issue: No ]
Efficacy: severity-weighted attack rate; muscle strength and mass measures; intolerable increase in attack frequency or severity necessitating withdrawal from the treatment period (HOP trial only).
Not Provided
Not Provided
Hyper- and Hypokalemic Periodic Paralysis Study
Dichlorphenamide vs. Placebo for Periodic Paralysis

The purpose of this study is to compare Dichlorphenamide with placebo (an inactive substance) for prevention of episodes and for improvement of strength in periodic paralysis. This study will also look at the long-term effects of Dichlorphenamide in periodic paralysis.

Periodic paralysis is a relatively rare, life-long disorder characterized by intermittent bouts of paralysis, progressive weakness, and diminished quality of life. Two drugs, acetazolamide and dichlorphenamide, have been prescribed to treat the disorder, however, dichlorphenamide is no longer available.

In this multi-center, parallel, randomized trial researchers will compare the effects of dichlorphenamide vs. placebo in patients with hyperkalemic (HYP) and hypokalemic (HOP) periodic paralysis.

The trial consists of two 9-week studies—one study will enroll persons with hyperkalemic periodic paralysis and the other study will enroll persons with hypokalemic periodic paralysis. Participants will be randomly assigned to one of two treatment groups: dichlorphenamide or placebo (an inactive substance). During the studies, participants will be asked to keep a daily diary to record the time, length, and severity of each episode of weakness. The study coordinator will contact participants weekly to review the diary information.

The 9-week phase will be followed by a 1-year open-label dichlorphenamide extension without placebo to determine the long-term effects of dichlorphenamide on the course of the disease and on inter-attack weakness.

Duration of the trial for participants is approximately 65 weeks, including a screening phase to determine eligibility, the first 9-week treatment phase, and the one-year open-label extension phase.

Phase 3
Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Treatment
Periodic Paralysis
  • Drug: Dichlorphenamide
    has been prescribed to treat periodic paralysis, but is no longer available
  • Drug: Placebo
    an inactive substance
  • Active Comparator: Dichlorphenamide
    Intervention: Drug: Dichlorphenamide
  • Placebo Comparator: Placebo
    inactive substance
    Intervention: Drug: Placebo
Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
May 2013
April 2013   (final data collection date for primary outcome measure)

Inclusion Criteria:

  • Genetically definite, clinically definite or clinically probable Hyperkalemic or Hypokalemic Periodic Paralysis as outlined in the protocol
  • Male and female participants, age 18 and older who are able to comply with the study conditions.
  • Participants who have distinct regular episodes of weakness with an average frequency of > or = to 1 a week and < or = to 3 a day either on or off treatment, whichever is higher
  • Normal thyroid-stimulating hormone (TSH) level

Exclusion Criteria:

  • Evidence for Andersen-Tawil syndrome (any one of the following 3 criteria)
  • Prolonged QT interval or complex ventricular ectopy between attacks
  • Distinctive physical features (2 out of 5)

    1. Low set ears
    2. Short stature
    3. Hypo-/micrognathia
    4. Clinodactyly
    5. Hypo-/hypertelorism
  • KIR 2.1 gene mutation
  • Coincidental renal, hepatic, active thyroid disease, restrictive or obstructive lung disease, other neuromuscular disease, or heart disease
  • Chronic, non-congestive, angle-closure glaucoma
  • Use of any of the following medications for reasons other than treatment of periodic paralysis: diuretics, antiarrhythmics, corticosteroids, beta-blockers, calcium channel blockers, antiepileptics, magnesium
  • History of life-threatening episodes of respiratory muscle weakness or cardiac arrhythmias during attacks
  • Pregnancy
  • Known mutation in the alpha subunit of the sodium channel gene in hypokalemic periodic paralysis patients
18 Years and older
Contact information is only displayed when the study is recruiting subjects
United States,   Italy,   United Kingdom
R01NS045686-02, CRC
Robert Griggs, MD, University of Rochester
University of Rochester
National Institute of Neurological Disorders and Stroke (NINDS)
Principal Investigator: Robert C. Griggs, M.D. University of Rochester
Principal Investigator: Rabi Tawil, M.D. Co-Principal Investigator, University of Rochester
Investigator: Michael McDermott, Ph.D. Biostatistician, University of Rochester
University of Rochester
February 2014

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP