Oral solution (Fintepla)
- Strengths
- 2.2 mg/mL
- Product note
- Strength is fenfluramine base; use supplied oral syringes.
Fenfluramine
Fintepla
DailyMed-verified antiseizure indications
Indication / use
- Label / evidence summary
- Fintepla: seizures associated with Dravet syndrome or Lennox-Gastaut syndrome from age 2 years.
- Role
- Maintenance
- Class
- Serotonergic pharmacology; proposed sigma-1 contribution
Indications checked 26 September 2026. Product, route, age, and treatment-role limits apply. A DailyMed listing alone does not establish FDA approval.
- Fintepla solution U.S. label
Dravet syndrome, Lennox-Gastaut syndrome · 2 years and older · Maintenance
Formulations & strengths
U.S. products unless another country is named. Strengths are per unit or stated volume.
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
- Age ≥2 years, oral solution 2.2 mg/mL: use the co-medication-specific table below. Without stiripentol: ceiling 0.35 mg/kg twice daily AND 26 mg/day. With stiripentol plus clobazam: ceiling 0.2 mg/kg twice daily AND 17 mg/day.
- Pediatric
- Same weight-based schedule from age 2; apply BOTH mg/kg and absolute daily caps. Renal/hepatic impairment or strong CYP1A2/CYP2D6 inhibitors can require lower caps.
- Titration / repeat dosing
- Without stiripentol: initial 0.1 → day 7 0.2 → day 14 0.35 mg/kg twice daily. With stiripentol plus clobazam: initial 0.1 → day 7 0.15 → day 14 0.2 mg/kg twice daily. For Dravet syndrome, increase according to response; for LGS, increase as tolerated to recommended maintenance.
Fintepla: co-medication-specific titration, age ≥2 years
| Phase | Without stiripentol | With stiripentol + clobazam |
|---|---|---|
| Initial | 0.1 mg/kg twice daily | 0.1 mg/kg twice daily |
| Day 7 | 0.2 mg/kg twice daily | 0.15 mg/kg twice daily |
| Day 14 | 0.35 mg/kg twice daily | 0.2 mg/kg twice daily |
| Maximum total daily dose | 26 mg/day AND weight-based ceiling | 17 mg/day AND weight-based ceiling |
Use the lower of the weight-based dose and absolute cap. Dravet syndrome: increase according to response; LGS: titrate as tolerated. Organ impairment and strong CYP inhibitors require separate limits.
Dose adjustment & concentrations
- Renal impairment
- Severe renal impairment (eGFR 15–29): maximum 20 mg/day without stiripentol or 17 mg/day with stiripentol plus clobazam; still respect the weight-based cap. End-stage renal disease is not studied.
- Hepatic impairment
- Without stiripentol: mild/moderate maximum 20 mg/day; severe 17 mg/day. With stiripentol plus clobazam: mild maximum 13 mg/day; moderate/severe not recommended. Respect weight-based ceilings.
- Serum reference information
- No established therapeutic range
Safety
- Boxed warning
- Valvular heart disease and pulmonary arterial hypertension; restricted FINTEPLA REMS program. Cases have been reported postmarketing despite none observed in DS/LGS clinical trials lasting up to 3 years (not all controlled trials).
- Contraindications
- Hypersensitivity; concomitant MAO inhibitors or use within the preceding 14 days.
- Serious precautions & monitoring
- Echocardiogram before treatment, every 6 months during treatment, and 3–6 months after the final dose. Monitor appetite, weight/growth, blood pressure and sedation; assess serotonin syndrome and glaucoma symptoms.
Common / selected adverse effects
- Decreased appetite
- Diarrhea
- Fatigue/lethargy
- Somnolence
- Weight decrease
- Pyrexia
Fintepla: Dravet syndrome studies 1–2, titration + maintenance (label §6.1, Table 4)
| Effect | 0.2 mg/kg/day (n=39) | 0.7 mg/kg/day (n=40) | 0.4 mg/kg/day + stiripentol/clobazam (n=43) | Pooled placebo (n=84) |
|---|---|---|---|---|
| Decreased appetite | 23% | 38% | 49% | 8% |
| Somnolence/sedation/lethargy | 26% | 25% | 23% | 11% |
| Diarrhea | 31% | 15% | 23% | 6% |
The 0.4 mg/kg/day group is not an intermediate exposure: stiripentol + clobazam increases fenfluramine exposure. Trial participants had Dravet syndrome; these rates are not LGS rates.
Drug interactions: toxicity & clinical action
| Partner / combination | Clinical effect | Clinical action |
|---|---|---|
| Stiripentol plus clobazam | Increases fenfluramine exposure and changes dose ceiling. | Use the stiripentol/clobazam regimen: maximum 0.2 mg/kg twice daily AND 17 mg/day. |
| Strong CYP1A2 or CYP2D6 inhibitors | Increased exposure. | Maximum 0.2 mg/kg twice daily AND 20 mg/day; consult label if other dose-limiting factors coexist. |
| MAO inhibitors / serotonergic drugs | Potential serotonin syndrome. | MAO inhibitors are contraindicated during and within 14 days; monitor other serotonergic combinations. |
| Strong CYP1A2/2B6/3A4 inducers / sedatives | Reduced effectiveness or additive sedation. | Avoid strong inducer combinations when possible; reassess dose when starting/stopping. |
Pregnancy & contraception
- Fetal / neonatal risk
- Human fenfluramine pregnancy data are insufficient to assess fetal risk. Animal studies found malformations, developmental loss and impaired growth with maternal toxicity at clinically relevant exposures.
- Pregnancy / postpartum monitoring
- Monitor maternal weight gain: fenfluramine can suppress appetite and cause weight loss.
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
- Randomized, double-blind, placebo-controlled Dravet syndrome studies used a 6-week baseline, 2-week titration, and 12–14-week maintenance; the Lennox-Gastaut syndrome study used a 4-week baseline and 14-week treatment.
- Primary endpoint
- Label primary result is model-derived difference relative to placebo, not median reduction: Dravet syndrome Study 1, −31.7% at 0.2 mg/kg/day and −70.0% at 0.7; Study 2 with stiripentol, −59.5% at 0.4. Ages 2–18; treatment 14/15 weeks.
- Results
- Dravet syndrome pivotal trials: median convulsive-seizure reductions were approximately 63–74% at 0.7 mg/kg/day versus 1–17% with placebo. Lennox-Gastaut syndrome trial: median drop-seizure reduction was 24% versus 7% with placebo.
- Responder rate
- Responder distributions are shown by regimen in label Figures 1–2; a single pooled percentage is not presented.
- Seizure freedom
- No convulsive seizures: Study 1 3/40 (8%) at 0.7 and 3/38 (8%) at 0.2 mg/kg/day vs 0 placebo over 14 weeks; Study 2 1/43 (2%) at 0.4 vs 0 over 15 weeks. Not all-seizure freedom.
Trial publications
Mechanism of action
- Fenfluramine and active norfenfluramine exhibit serotonin 5-HT2 receptor agonist activity. The precise mechanism underlying seizure control is unknown.
- Positive sigma-1 modulation by fenfluramine has been demonstrated in cellular and animal assays. This remains a proposed contribution, not a proven second clinical mechanism; parent and metabolite do not show identical sigma-1 effects.
- 5-HT2B-related pharmacology is relevant to valvular heart disease and pulmonary arterial hypertension risk; it must not be conflated with a demonstrated therapeutic target.
Pharmacology
Adult values unless specified. Vd/F denotes apparent oral distribution volume.
Pharmacokinetics
- Bioavailability
- Absolute oral bioavailability approximately 68–74%; food does not meaningfully affect exposure.
- Elimination half-life
- Approximately 20 hours.
- Volume of distribution
- Apparent oral Vz/F approximately 11.9 L/kg in healthy subjects (U.S. label).
- Active metabolite(s)
- Yes: norfenfluramine.
- Active-metabolite half-life
- Approximately 30 hours (Fintepla UK/European product information).
- Protein binding
- ~50%
- Metabolism / elimination
- CYP1A2, CYP2B6, CYP2D6; additional pathways
Stiripentol-containing regimens and enzyme inhibitors alter the balance of parent and metabolite exposure; use the product-specific dose limits.
Molecular structure
NIH PubChem structure and record ↗
Product history
- Initial U.S. approval
- 2020 (for epilepsy; earlier anorectic withdrawn)
- Market / formulation history
- 2020 for epilepsy
- Brands
- Fintepla
- Manufacturer / marketer
- UCB (Fintepla)
- Generic availability
- No
- Related drugs
- Former anorectic repurposed at lower doses for epilepsy; active metabolite is norfenfluramine.
Sources & review status
Indications and DailyMed PDFs checked: 2026-09-26. Other profile sources reviewed: 2026-09-15 · label revision noted at that review: 10/2025. This is a draft reference; final review is pending.