THERAPEUTICS

Brands

• Potiga

Generic?

• No

Class

• Antiepileptic drug (AED)

Commonly Prescribed for

(FDA approved in bold)

• Adjunctive treatment of partial-onset seizures in patients ≥ 18 years old who have responded inadequately to several alternative treatments and for whom the benefits outweigh the risk of retinal abnormalities and potential decline in visual acuity

How the Drug Works

• Ezogabine stabilizes the resting membrane potential and reduces brain excitability by keeping transmembrane potassium channels (KCNQ2, KCNQ3) open longer and delaying membrane repolarization (stabilizes M-current resting membrane potential). It may also potentiate GABAA receptors

How Long Until It Works

• Tmax 0.5–2 hours. Clinical effects may take weeks to months

If It Works

• Periodic ophthalmological and urological monitoring. May consider tapering after seizure free for 2 years, depending on the seizure type

If It Doesn't Work

• Consider changing to another agent, adding a second agent, using a medical device, or a referral for epilepsy surgery evaluation. When adding a second agent, keep drug interactions in mind

Best Augmenting Combos for Partial Response or Treatment-Resistance

• Not available

Tests

• No test required

ADVERSE EFFECTS (AEs)

How the Drug Causes AEs

• Affecting potassium channels in brain and bladder

Notable AEs

• Urinary retention (2%), skin discoloration (lips, nail beds, etc.), neuropsychiatric symptoms (confusion, psychosis, hallucination), dizziness, somnolence, QTc prolongation (7.7 ms at 1200 mg/day), withdrawal seizure, abuse potential

Life-Threatening or Dangerous AEs

• Retinal dystrophy (perivascular pigmentation, focal retinal epithelium clumping), vision loss, suicidal behavior

Weight Gain

• Common

• Dose-related weight gain

Sedation

• Not unusual

What to Do About AEs

• Discontinue and switch to another agent

Best Augmenting Agents to Reduce AEs

• Alcohol worsens the adverse reaction

DOSING AND USE

Usual Dosage Range

• 600–1200 mg 3 times daily, with or without food, swallowed whole

Dosage Forms

• Tablets: 50, 200, 300, and 400 mgagents or antineoplastic agents