Tablet (Potiga; Discontinued)
- Strengths
- 50, 200, 300, 400 mg
- Product note
- Historical U.S. strengths; Trobalt is the former EU brand.
Ezogabine (retigabine)
Potiga (U.S.) / Trobalt (EU) · Discontinued
Historical antiseizure indications · Discontinued
Indication / use
- Label / evidence summary
- Discontinued. Historical Potiga indication: adjunctive focal-onset seizures in adults ≥18 years who responded inadequately to several alternatives and for whom benefits outweighed retinal / vision risks.
- Role
- Historical maintenance use · Discontinued
- Class
- Potassium-channel opener
Historical reference only. The linked FDA PDF is an archived label, not a current DailyMed product label. Discontinued marketing status does not by itself establish the reason for discontinuation or withdrawal of approval.
- Potiga tablets (Discontinued) Discontinued · historical U.S. label
Focal seizures · 18 years and older (historical label) · MaintenanceHistorical restricted adjunctive use after several alternatives proved inadequate; retinal risks required specific benefit–risk assessment.
Formulations & strengths
Archived U.S. label; historical strengths, not current availability.
Brand & formulation labels
Each link names the product and formulation it covers. Archived labels do not establish current availability.
Dosing & administration
- Adult / product-specific schedule
- Historical label: start 100 mg three times daily; increase at weekly intervals by no more than 50 mg per dose (150 mg/day total). Maintenance 200–400 mg three times daily (600–1,200 mg/day). The highest dose had limited added benefit and more adverse effects versus 900 mg/day.
- Pediatric
- Historical U.S. indication was adults 18 years and older; pediatric safety and effectiveness were not established.
- Titration / repeat dosing
- Historical dosing only. Taper over at least 3 weeks unless a safety concern requires faster withdrawal. For age ≥65, start 50 mg three times daily; maximum 250 mg three times daily.
- Dose basis
- Historical archived-label dosing for a discontinued drug; included for reference, not current prescribing.
Practical administration
- Product instructions
- Historical label: swallow tablets whole; take with or without food in three equal daily doses.
Dose adjustment & concentrations
- Renal impairment
- Historical label for creatinine clearance <50 mL/min or hemodialysis: start 50 mg three times daily; maximum 200 mg three times daily. Dialysis required specific supplemental-dose instructions in the label.
- Hepatic impairment
- Historical label: Child-Pugh 7–9, start 50 mg three times daily and maximum 250 mg three times daily; Child-Pugh >9, same starting dose and maximum 200 mg three times daily.
- Serum reference information
- No established therapeutic serum range is supplied in the cited label.
Safety
- Boxed warning
- Retinal abnormalities with potential vision loss. Archived label required baseline and 6-monthly ophthalmic monitoring, with discontinuation considered for retinal pigmentation or vision changes.
- Contraindications
- None listed in the archived U.S. label; this does not remove its boxed warning or major precautions.
- Serious precautions & monitoring
- Retinal and skin pigmentation, vision loss, urinary retention, neuropsychiatric symptoms, QT prolongation, dizziness / somnolence and suicidal thoughts or behavior.
Common / selected adverse effects
- Dizziness
- Somnolence
- Fatigue
- Confusion / impaired coordination
- Blurred vision
Selected label-reported effects; frequencies cannot be compared across drugs.
Drug interactions: toxicity & clinical action
| Partner / combination | Clinical effect | Clinical action |
|---|---|---|
| Carbamazepine / phenytoin | May lower ezogabine exposure. | Historical label advises considering a dose increase; reassess when the interacting drug is withdrawn. |
| Digoxin | N-acetyl metabolite may inhibit renal digoxin transport. | Monitor digoxin concentrations. |
| Alcohol / other sedatives | Increased ezogabine exposure with alcohol and/or additive CNS impairment. | Review combined exposure and impairment risk. |
| QT-prolonging drugs | Potential additive QT risk. | Review ECG and risk factors under specialist supervision. |
Selected interactions; consult the full label and complete medication list.
Pregnancy & contraception
- Fetal / neonatal risk
- Inadequate human pregnancy data; animal studies showed developmental toxicity at clinically relevant exposures. Archived label requires assessment of potential fetal harm.
Clinical evidence
Research summaries describe studied populations and outcomes; they do not add indications or constitute treatment recommendations.
Direct pivotal trial
Trial summary
- Study design / duration
- RESTORE 1: randomized, double-blind, placebo-controlled adjunctive trial; 305 treated adults; 18-week treatment period.
- Primary endpoint
- Percentage change in focal-seizure frequency
- Results
- At 1,200 mg/day, median focal-seizure reduction was 44.3% versus 17.5% with placebo. At least 50% reduction occurred in 44.4% versus 17.8%; adverse-event discontinuations were 26.8% versus 8.6%. This historical trial does not imply current product availability.
Trial publications
Comparative evidence
- Findings
- No head-to-head efficacy comparison is summarized.
Mechanism of action
- In vitro, enhances potassium currents through KCNQ (Kv7.2–Kv7.5) channels, stabilizing resting membrane potential and reducing excitability.
- The archived label also describes possible augmentation of GABA-mediated currents; the therapeutic mechanism is not fully established.
Pharmacology
Adult values unless specified. Vd/F denotes apparent oral distribution volume.
Pharmacokinetics
- Bioavailability
- Approximately 60% absolute oral bioavailability.
- Elimination half-life
- Ezogabine and its N-acetyl metabolite have similar elimination half-lives of 7–11 hours.
- Volume of distribution
- Steady-state volume of distribution 2–3 L/kg after IV dosing.
- Active metabolite(s)
- N-acetyl metabolite (NAMR) has antiseizure activity but is less potent in animal models; major N-glucuronides are inactive.
- Active-metabolite half-life
- N-acetyl metabolite: 7–11 hours.
- Protein binding
- Ezogabine approximately 80%; N-acetyl metabolite approximately 45%.
- Metabolism / elimination
- Mainly glucuronidation and acetylation; renal elimination predominates. No oxidative CYP-mediated metabolism demonstrated in the label’s in-vitro studies.
Values reflect the cited product and study population; they are not interchangeable across formulations.
Molecular structure
NIH PubChem structure and record ↗
Product history
- Initial U.S. approval
- June 10, 2011 — Potiga (NDA 022345)
- Market / formulation history
- All U.S. Potiga strengths are listed as Discontinued. EMA records withdrawal of Trobalt’s EU authorization on July 19, 2018, at the holder’s request for commercial reasons.
- Brands
- Potiga (U.S.) / Trobalt (EU) · Discontinued
- Manufacturer / marketer
- GlaxoSmithKline in the archived Potiga label
- Generic availability
- No currently marketed U.S. product is identified in the cited FDA application.
- Related drugs
- Other KCNQ-channel modulators under investigation are separate compounds and do not inherit this approval.
Sources & review status
Archived FDA label and product marketing status checked: 2026-09-27. Other profile sources reviewed: 2026-09-27 · label revision noted at that review: Archived FDA Potiga label: May 2016.. This is a draft reference; final review is pending.