Evidence map›Paper›PMID 34129236›Full record

Trial reportMuscle & nerve2021

Long-term efficacy and safety of dichlorphenamide for treatment of primary periodic paralysis.

Valeria A Sansone, Nicholas E Johnson, Michael G Hanna, Emma Ciafaloni, Jeffrey M Statland, Perry B Shieh, Fredric Cohen, Robert C Griggs

Open access · hybridAbstract readRandomized Controlled Trial
In one paragraph

Trial report in Muscle & nerve, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.

0numbers the graph read from it
0cells of the map it votes in
4citing papers in PubMed
0.5field-weighted citation impact, top 38% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

4 citing papers in PubMed, 11 citations in OpenAlex.

  1. Trial
  2. Permanent weakness and myopathy in hypokalemic periodic paralysis.Acta myologica : myopathies and cardiomyopathies : official journal of the Mediterranean Society of Myology · 2026
    Review
  3. Review
  4. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors at 7 institutions in 3 countries.

Valeria A SansoneNeuromuscular Omnicentre, Neurorehabilitation Unit, University of Milan, Niguarda Hospital, Milan, Italy.
Nicholas E JohnsonDepartment of Neurology, Virginia Commonwealth University, Richmond, Virginia, USA.ORCID 0000-0002-3917-4257
Michael G HannaMRC Centre for Neuromuscular Diseases, Department of Neuromuscular Diseases, UCL Institute of Neurology, London, UK.
Emma CiafaloniDepartment of Neurology, University of Rochester Medical Center, Rochester, New York, USA.
Jeffrey M StatlandDepartment of Neurology, University of Kansas Medical Center, Kansas City, Kansas, USA.ORCID 0000-0003-0790-5315
Perry B ShiehDepartment of Neurology, Ronald Reagan UCLA Medical Center, Los Angeles, California, USA.ORCID 0000-0001-7145-7663
Fredric CohenStrongbridge Biopharma, Trevose, Pennsylvania, USA.
Robert C GriggsDepartment of Neurology, University of Rochester Medical Center, Rochester, New York, USA.
University of Rochester Medical Center · USBridge Pharma (United States) · USMolecular Cardiology and Neuromuscular Institute · USRonald Reagan UCLA Medical Center · USUniversity of Kansas Medical Center · USUniversity of Milan · ITVirginia Commonwealth University · US

Funding

Dichlorphenamide vs Acetazolamide for Periodic ParalysisR01NS045686 · NINDS · UNIVERSITY OF ROCHESTER · PI GRIGGS, ROBERT C · 2004 to 2010
$5.7M
NINDS NIH HHS R01 NS045686
6 · The paper itself

Abstract

INTRODUCTION/

aimLong-term efficacy and safety of dichlorphenamide (DCP) were characterized in patients with primary periodic paralysis (PPP).

methodsPatients with PPP in a double-blind, placebo-controlled study were randomly assigned to receive DCP 50 mg twice daily or placebo for 9 weeks, followed by a 52-week open-label DCP treatment phase (DCP/DCP and placebo/DCP populations). Efficacy (attack rate, severity-weighted attack rate) and safety were assessed in patients completing the study (61 weeks). In this post hoc analysis, efficacy and safety data were pooled from hyperkalemic and hypokalemic substudies.

resultsSixty-three adults (age, 19-76 years) completed the double-blind phase; 47 (74.6%) of these patients completed 61 weeks. There were median decreases in weekly attack and severity-weighted attack rates from baseline to week 61 (DCP/DCP [n = 25], -1.00 [P < .0001]; placebo/DCP [n = 20], -0.63 [P = .01] and DCP/DCP, -2.25 [P < .0001]; placebo/DCP, -1.69 [P = .01]). Relatively smaller median decreases in weekly attack and severity-weighted attack rates occurred from weeks 9 to 61 among patients receiving DCP continuously (n = 26; -0.14 [P = .1] and -0.24 [P = .09]) than among those switching from placebo to DCP after 9 weeks (n = 16; -1.04 [P = .049] and -2.72 [P = .08]). Common adverse events (AEs) were paresthesia and cognition-related events, which typically first occurred within 1 month of blinded treatment initiation and in rare cases led to treatment discontinuation. Dose reductions were frequently associated with common AE resolution. DISCUSSION: One-year open-label DCP treatment after a 9-week randomized, controlled study confirmed long-term DCP remains safe and effective for chronic use. Tolerability issues (paresthesia, cognition-related AEs) were manageable in most patients.

Indexed as

AdultAgedCarbonic Anhydrase InhibitorsDichlorphenamideDouble-Blind MethodFemaleHumansMaleMiddle AgedParalyses, Familial PeriodicTreatment OutcomeYoung AdultCarbonic Anhydrase InhibitorsDichlorphenamideefficacyhypokalemic periodicparalysissafetyweakness

Identifiers

PMID34129236
PMCPMC9290603
OpenAlexW3168725723

What OpenQuestion holds

Textmetadata
LicenceCC BY-NC-ND
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.