World Library  
Flag as Inappropriate
Email this Article


Article Id: WHEBN0022160923
Reproduction Date:

Title: Retigabine  
Author: World Heritage Encyclopedia
Language: English
Subject: ATC code N03, Potassium channel opener
Publisher: World Heritage Encyclopedia


Retigabine (INN) or ezogabine (USAN), codenamed D-23129, is an anticonvulsant used as a treatment for partial epilepsies. The drug was developed by Valeant Pharmaceuticals and GlaxoSmithKline. It was approved by the European Medicines Agency under the trade name Trobalt on March 28, 2011, and by the United States Food and Drug Administration (FDA), under the trade name Potiga, on June 10, 2010.

Retigabine works primarily as a potassium channel opener—that is, by activating a certain family of voltage-gated potassium channels in the brain.[1][2][3] This mechanism of action is unique among antiepileptic drugs, and may hold promise for the treatment of other neurologic conditions, including migraine, tinnitus[4] and neuropathic pain.


Among the newer anticonvulsants, retigabine was one of the most widely studied in the preclinical setting: it was the subject of over 100 published studies before clinical trials began. In preclinical tests, it was found to have a very broad spectrum of activity—being effective in nearly all the animal models of seizures and epilepsy used: retigabine suppresses seizures induced by electroshock, electrical kindling of the amygdala, pentylenetetrazol, kainate, NMDA, and picrotoxin.[5] Researchers hoped this wide-ranging activity would translate to studies in humans as well.[6]

Clinical trials

In a double-blind, randomized, placebo-controlled Phase II clinical trial, retigabine was added to the treatment regimen of 399 participants with partial seizures that were refractory to therapy with other antiepileptic drugs. The frequency with which seizures occurred was significantly reduced (by 23 to 35%) in participants receiving retigabine, and approximately one fourth to one third of participants had their seizure frequency reduced by more than 50%. Higher doses were associated with a greater response to treatment.[6][7][8]

A Phase II trial meant to assess the safety and efficacy of retigabine for treating postherpetic neuralgia was completed in 2009, but failed to meet its primary endpoint. Preliminary results were reported by Valeant as "inconclusive".[9]

Regulatory approval

The U.S. Food and Drug Administration accepted Valeant's New Drug Application for retigabine on December 30, 2009.[10] The FDA Peripheral and Central Nervous System Drugs Advisory Committee met on August 11, 2010 to discuss the process and unanimously recommended approval of Potiga for the intended indication (add-on treatment of partial seizures in adults).[11][12] However, the possibility of urinary retention as an adverse effect was considered a significant concern, and the panel's members recommended that some sort of monitoring strategy be used to identify patients at risk of bladder dysfunction.[11] Potiga was approved by the FDA on June 10, 2010, and is set to become available on the U.S. market after scheduling by the Drug Enforcement Administration.[13]

In December 2011, the U.S. Drug Enforcement Administration (DEA) placed the substance into Schedule V of the Controlled Substances Act (CSA), the category for substances with a comparatively low potential for abuse. This became effective 15 December 2011.[14]

Adverse effects

The adverse effects found in the Phase II trial mainly affected the central nervous system, and appeared to be dose-related.[6] The most common adverse effects were drowsiness, dizziness and vertigo, confusion, and slurred speech.[8] Less common side effects included tremor, memory loss, gait disturbances, and double vision.[7] In 2013 FDA warned the public that, Potiga (Ezogabine) can cause blue skin discoloration and eye abnormalities characterized by pigment changes in the retina. FDA does not currently know if these changes are reversible. FDA is working with the manufacturer to gather and evaluate all available information to better understand these events. FDA will update the public when more information is available. [15] Psychiatric symptoms and difficulty urinating have also been reported, with most cases occurring in the first 2 months of treatment.[13][16]

The drug can cause blue skin dyscoloration and pigment changes in the eye's retina. It is not known whether these effects are reversible or not.[17]


Retigabine appears to be free of drug interactions with most commonly used anticonvulsants. It may increase metabolism of lamotrigine (Lamictal), whereas phenytoin (Dilantin) and carbamazepine (CBZ, Tegretol) increase the clearance of retigabine.[16][18]

Concomitant use of retigabine and digoxin may increase serum concentration of the latter. In vitro studies suggest that the main metabolite of retigabine acts as a P-glycoprotein inhibitor, and may thus increase absorption and reduce elimination of digoxin.[16]


Retigabine is quickly absorbed, and reaches maximum plasma concentrations between half an hour and 2 hours after a single oral dose. It has a moderately high oral bioavailability (50–60%), a high volume of distribution (6.2 L/kg), and a terminal half-life of 8 to 11 hours.[18] Retigabine requires thrice-daily dosing due to its short half-life.[6][8][16]

Retigabine is metabolized in the liver, by N-glucuronidation and acetylation. The cytochrome P450 system is not involved. Retigabine and its metabolites are excreted almost completely (84%) by the kidneys.[16][18]

Mechanism of action

Retigabine acts as a neuronal KCNQ/Kv7 potassium channel opener, a mechanism of action markedly different from than of any current anticonvulsants.[1][2][3] This mechanism of action is similar to that of the chemically-similar flupirtine,[19] which is used mainly for its analgesic properties.


The International Nonproprietary Name "retigabine" was initially published as being under consideration by WHO in 1996.[20] This was later adopted as the recommended International Nonproprietary Name (rINN) for the drug, and, in 2005 or 2006, the USAN Council—a program sponsored by the American Medical Association, the United States Pharmacopeial Convention, and the American Pharmacists Association that chooses nonproprietary names for drug sold in the United States—adopted the same name.[21] In 2010, however, the USAN Council rescinded its previous decision and assigned "ezogabine" as the United States Adopted Name for the drug.[22] The drug will thus be known as "ezogabine" in the United States and "retigabine" elsewhere.


Further reading

External links

  • Valeant Pharmaceuticals International: Neurology Pipeline
  • Miami Children's Brain Institute - Retigabine

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.