General Information

Potiga (ezogabine) is a potassium channel agent. The mechanism by which ezogabine exerts its therapeutic effects has not been fully elucidated. However it appears to work by enhancing transmembrane potassium currents mediated by the KCNQ family of ion channels and through augmentation of GABA-mediated currents. Gamma-amino butyric acid (GABA) is an inhibitory neurotransmitter that may help suppress seizure activity.

Potiga is specifically indicated as adjunctive treatment of partial-onset seizures in adults.

Potiga is supplied as a tablet for oral administration. The recommended initial dose is 100 mg three times daily. The dosage should be increased gradually at weekly intervals by no more than 50 mg three times daily (increase in the daily dose of no more than 150 mg per day) up to a maintenance dosage of 200 to 400 mg three times daily (600 to 1,200 mg per day), based on individual response and tolerability.

Clinical Results

FDA Approval
The FDA approval of Potiga was based on three multicenter, randomized, double-blind, placebo-controlled studies in 1,239 adult subjects. All subjects had partial onset seizures with or without secondary generalization and were not adequately controlled with up to three concomitant AEDs. During the titration phase of all three studies, treatment was initiated at 300 mg/day (100 mg three times per day) and increased in weekly increments of 150 mg/day to the target maintenance dosage. The total daily maintenance dosages were 600 mg/day, 900 mg/day, or 1,200 mg/day, each administered in three equally divided doses. The primary endpoint consisted of the percent change in seizure frequency from baseline in the double-blind treatment phase. A statistically significant improvement from baseline was observed with all doses of Potiga compared to placebo in all three studies.

Side Effects

Adverse events associated with the use of Potiga may include, but are not limited to, the following:

• dizziness
• somnolence
• fatigue
• confusional state
• vertigo
• tremor
• abnormal coordination
• diplopia
• disturbance in attention
• memory impairment
• asthenia
• blurred vision
• gait disturbance
• aphasia
• dysarthria
• balance disorder

Mechanism of Action

Potiga (ezogabine) is a potassium channel agent. The mechanism by which ezogabine exerts its therapeutic effects has not been fully elucidated. In vitro studies indicate that ezogabine enhances transmembrane potassium currents mediated by the KCNQ family of ion channels. By activating KCNQ channels, ezogabine is thought to stabilize the resting membrane potential and reduce brain excitability. In vitro studies suggest that ezogabine may also exert therapeutic effects through augmentation of GABA-mediated currents. Gamma-amino butyric acid (GABA) is an inhibitory neurotransmitter that may help suppress seizure activity.

Literature References

French JA, Abou-Khalil BW, Leroy RF, Yacubian EM, Shin P, Hall S, Mansbach H, Nohria V; RESTORE 1/Study 301 Investigators Randomized, double-blind, placebo-controlled trial of ezogabine (retigabine) in partial epilepsy. Neurology 2011 May 3;76(18):1555-63. Epub 2011 Mar 30

Owen RT Ezogabine: a novel antiepileptic as adjunctive therapy for partial onset seizures. Drugs Today 2010 Nov;46(11):815-22

Brodie MJ, Lerche H, Gil-Nagel A, Elger C, Hall S, Shin P, Nohria V, Mansbach H; RESTORE 2 Study Group Efficacy and safety of adjunctive ezogabine (retigabine) in refractory partial epilepsy. Neurology 2010 Nov 16;75(20):1817-24. Epub 2010 Oct 13

Additional Information

For additional information regarding Potiga or partial onset epilepsy, please visit the Valeant web page.