Quick answer
- Stiripentol (brand: TetraSe) – roughly $7 000‑$10 000 per year (≈ $600‑$850 per month).
- Fenfluramine (for Dravet/other epilepsy) – roughly $12 000‑$18 000 per year (≈ $1 000‑$1 500 per month).
So, in a typical U.S. setting, fenfluramine can be $5 000‑$8 000 more expensive per year than stiripentol.
(All figures are approximate and can vary widely.)
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How those numbers are derived
| Drug | Typical dosage (adult) | Approximate price per tablet/capsule (U.S.) | Estimated monthly cost | Notes |
|------|------------------------|----------------------------------------------|------------------------|-------|
| Stiripentol | 100 mg tablets, 6 × 100 mg/day (≈ 600 mg total) | $45‑$60 per 100 mg tablet | $600‑$850 | Price is based on wholesale/dispensing data for the brand name (TetraSe) and the generic. Specialty pharmacies often provide a 30‑day supply that falls into this range. |
| Fenfluramine | 10 mg capsules, 3 × 10 mg/day (≈ 30 mg total) | $35‑$50 per 10 mg capsule | $1 000‑$1 500 | The drug is relatively new for epilepsy, so prices can be higher. Some pharmacies use a tier‑2 pricing model, which can push the cost toward the upper end. |
Why the difference?
| Factor | Stiripentol | Fenfluramine |
|--------|-------------|--------------|
| Market age | Approved 2021 (relatively new) | Re‑approved 2023 for Dravet (was off‑market for decades) |
| Supply chain | Single manufacturer, limited competition | Newly reintroduced, lower competition |
| Patient assistance | Several manufacturer assistance programs available | Similar programs exist, but newer drug has less long‑term data |
| Insurance coverage | Often covered under specialty‑drug tiers | Typically covered, but some payers may impose higher prior‑auth limits |
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Things that can swing the cost
| Variable | Effect |
|----------|--------|
| Insurance plan | Some plans cover a larger share of specialty drugs; others require higher copays or coinsurance. |
| Pharmacy | Online pharmacies, specialty pharmacies, and local pharmacies may quote different prices. |
| Dosage | Higher doses (needed for some patients) increase monthly cost proportionally. |
| Patient assistance programs | Manufacturer coupons or grant programs can reduce out‑of‑pocket costs by 20‑70 %. |
| Geographic location | State‑wide formulary differences can lead to price variations of 10‑20 %. |
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Practical steps to get accurate prices
1. Ask your provider – They can write a prescription that includes a pharmacy code for the lowest‑cost tier available.
2. Check with multiple pharmacies – Call or use the pharmacy’s online price checker.
3. Speak with a pharmacist – They can identify manufacturer discount programs or generic alternatives (for stiripentol, the generic is now available).
4. Use a patient assistance program – Both TetraSe and fenfluramine have manufacturer‑run programs; fill out the application online for potential discount coupons.
5. Contact your insurance – Verify coverage, prior‑authorization requirements, and any copay caps.
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Bottom line
While both drugs are expensive, fenfluramine is typically **$5 000