Conditions: Hyperkalemic Periodic Paralysis Hypokalemic Periodic Paralysis
Keywords: periodic paralysis dichlorphenamide
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 71
Healthy volunteers: no

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

Detailed description:
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 (ACZ) 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 (attack). 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.

Arms:
arm 1: Hyperkalemic participants were randomized to Dichlorphenamide for a 9 week double-blind phase. All participants then received Dichlorphenamide for a 52 week open-label phase. arm 2: Hyperkalemic participants were randomized to Placebo for a 9 week double-blind phase. All participants then received Dichlorphenamide for a 52 week open-label phase. arm 3: Hypokalemic participants were randomized to Dichlorphenamide for a 9 week double-blind phase. All participants then received Dichlorphenamide for a 52 week open-label phase. arm 4: Hypokalemic participants were randomized to Placebo for a 9 week double-blind phase. All participants then received Dichlorphenamide for a 52 week open-label phase.

Interventions: intervention 1: Dichlorphenamide (double-blind) intervention 2: Placebo (double-blind) intervention 3: Dichlorphenamide (open-label)
Intervention descriptions: intervention 1: 50mg tablet; maximum dosage 400mg/day intervention 2: Inactive substance manufactured to look like Dichlorphenamide 50mg tablet intervention 3: 50mg tablet; maximum dosage 400mg/day

Protocol document: