Fenfluramine
Aliases: Pondimin, Fintepla
Summary
Fenfluramine was withdrawn from market as an appetite suppressant in 1997 due to cardiotoxicity (valvular heart disease and pulmonary hypertension). Reintroduced in 2020 for seizures associated with Dravet syndrome and Lennox-Gastaut syndrome at lower therapeutic doses. Available only through restricted REMS program requiring cardiac monitoring via echocardiogram.
Dose Information
Light
Common
Strong
Heavy
Onset, Duration & After-effects
| ROA | Onset | Comeup | Peak | Offset |
|---|---|---|---|---|
| Oral | 30-60 min | 1-2 hrs | 3-5 hrs | 3-6 hrs |
Tolerance
Build-up
develops over days to weeks of regular use
Reset
3–7 days for acute; 1–3 weeks for full reset
Tolerance Decay
Full tolerance
0h
Half tolerance
0d
Baseline
~0d
Robust human data describing pharmacodynamic tolerance to fenfluramine’s antiseizure effect are lacking; some tolerance to anorectic effects likely develops with repeated exposure, as seen historically with serotonergic anorectics, but magnitude and timeline are poorly characterized. Treat as unknown; avoid dose escalation outside medical guidance.
Cross-Tolerances
Effects
Positive
- Muscle relaxation
- Anxiolytic
- Muscle Relaxant
- Physical euphoria
Negative
- Lethargy
- Nausea
- Motor impairment
- Respiratory depression
- Sedation
- Sedative
Positive
- Euphoria
- Anxiety suppression
Negative
- Anxiety
- Dizziness
- Cognitive impairment
- Amnesia
- Motor control loss
- Thought deceleration
- Decreased arousal
- Time distortion
Negative
- Appetite suppression
- Disinhibition
- Decreased Libido
- Acuity Suppression
- Visual acuity suppression
- Acuity suppression
- Hallucinations
- Dulled perception
- Perception of bodily heaviness
- Appetite fluctuation
Combinations
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