Zonisade Generic: When Will Generic Zonisamide Be Available?
This page is aggregated from FDA records, court filings and company announcements. Coded and designed by Dr. Brian Staiger, PharmD, BCPS
Updated October 9, 2026 How we build our data
Zonisade Generic at a Glance
Four quick answers from FDA records and our estimate.
- When is the first generic expected? September 2027 About 11 months away Why then?
- Has the FDA approved a generic? December 2005 7 companies approved
- When does the last patent end? August 2038 4 patents listed with the FDA Why is a generic expected sooner?
- Can you buy a generic today? Yes 25 companies list one
It already is. A generic zonisamide is listed for sale by 25 companies, so ask your pharmacy whether it can fill your prescription with one.
Why September 2027?
When a generic maker challenges a patent, FDA must wait up to 30 months before approving it. That wait ends then. We rate it probable: more likely than not, but it can still move.
If Zonisade’s last patent runs to August 2038, how can a generic come sooner?
The 4 patents that run past the expected month, to August 2038 (11,478,456, 11,529,333, 12,491,179 and 12,685,723), cover a way of using it and the product’s formulation. A patent like that protects one way of making or using the medicine, not the medicine itself. A generic company can often make its version a different way or leave that use off its label, or a court can rule the patent invalid or not infringed. Generic companies have been challenging Zonisade’s patents with the FDA since February 2025. That is why the expected month comes before the last protection ends. See the road to a generic
What should I do now?
Ask your pharmacy whether it can fill your prescription with a generic. It may look different from Zonisade, but the active ingredient, strength and form are the same. What a generic means for you
Our month is only an estimate based on available information, so we never name a day.
Zonisade by the Numbers
- Reason
- Court hold endsWhen a generic maker challenges a patent, FDA must wait up to 30 months before approving it. That wait ends then.
- How sure
- Probable More likely than not, but it can still move.
- Price competition
- Moderate 3 companies have filed, 1 first in line
- Brand sales
- $63M a yearSmaller seller
- FDA approved 2022 July 2022 FDA Orange Book
- Patents listed 4 last runs to August 2038 FDA Orange Book
- Generics FDA-approved 7 companies, the first approved December 2005 FDA Orange Book
- Pharmacies pay $2.75 per mL, up 17.2% in a year NADAC, October 2026
- Medicare Part D spent $6.6M in 2025, for 665 people CMS Part D Spending by Drug
- Medicaid prescriptions 39.6K in the last four reported quarters, $34.9M CMS Medicaid drug utilization, to Q1 2026
Zonisade’s Road to a Generic
Zonisade has had the market to itself since the FDA approved it in July 2022 (Azurity Pharmaceuticals Inc). Its 4 listed patents run to August 2038. Generic companies have challenged its patents with the FDA since February 2025.
The first generic of Zonisade is expected in September 2027.
Why that month: when a generic maker challenges a patent, FDA must wait up to 30 months before approving it. That wait ends then. That is about 11 years before the last listed patent runs out, in August 2038.
Why a Generic Can Come Before August 2038
The last listed patent runs to August 2038, but it covers a way of using it and the product’s formulation, not the medicine itself, which a generic can often work around or challenge. Dr. Brian explains
Each bar runs from the brand’s approval to the day that protection ends. The green band is our projection for the first generic: a month, never a day, because legal dates move and a generic reaches shelves days to weeks after it is allowed. Sources: FDA Orange Book; the expected month from court records and company announcements.
Zonisade Patents and FDA Protections
Every patent and exclusivity the FDA Orange Book lists for Zonisade’s own applications. A protection running past the expected month does not mean the date is wrong: a settlement or a court ruling can let a generic in before a patent ends, and a patent on one formulation or use does not block every generic.
| Patent | What it covers | Protects until | Status |
|---|---|---|---|
| 11,478,456 | A way of using it (U-3458) | August 2038 | Active |
| 11,529,333 | The product’s formulation | August 2038 | Active |
| 12,491,179 | The product’s formulation | August 2038 | Active |
| 12,685,723 | The product’s formulation | August 2038 | Active |
Source: FDA Orange Book, application 214273. Patent numbers open the patent on Google Patents.
Patent Challenges to Zonisade
The first patent challenge to Zonisade reached the FDA in February 2025, from one company on that first day. The FDA has not approved a first challenger’s generic yet.
What Is a Patent Challenge?
A generic company that wants to sell its version before Zonisade’s patents run out can tell the FDA that a patent is invalid, or that its version does not infringe it. The FDA calls this a “Paragraph IV certification.” The brand company usually sues, and the FDA then generally cannot approve that generic for up to 30 months while the case runs. To reward going first, the companies that challenge first can get a 180-day head start: the FDA cannot approve the generics that came after them until it ends.
| Product | First challenged | Companies that day | 180-day head start | First challenger’s generic | Challenged patents run to | |
|---|---|---|---|---|---|---|
| Approved | On sale | |||||
| Oral suspension, 100 mg/5 mL | February 2025 | 1 company | No decision yet | Not yet | Not yet | August 2038 |
Source: the FDA’s Paragraph IV Patent Certifications list, as of September 2026. The FDA began posting the 180-day decisions and the first challenger’s approval and first sale in June 2019: an older entry it has not updated since reads “Not posted”, and “Not yet” means the list records no such event. “Companies that day” is the FDA’s count of challenges that arrived on the first day.
Who Is Lined Up to Make Generic Zonisamide
Three steps stand between a brand and a generic you can buy: a company applies to the FDA, the FDA approves it, and the company starts selling it.
Applied to the FDA
At least 7 companies have applied to the FDA to make generic zonisamide.
First in line. One of them was first in line: the first company to challenge the brand’s patents can earn 180 days on the market before the other generics, which is why being first matters.
Generic companies have challenged Zonisade’s patents with the FDA since February 2025: see the patent challenges.
Approved by the FDA
The FDA has approved generic versions from 7 companies, the first in December 2005. Approved is not the same as on sale: patents, a settlement or the company’s own plans can still hold a launch.
For Sale in Pharmacies
Yes. A generic zonisamide is listed for sale by 25 companies. Ask your pharmacy whether it can fill your prescription with it.
Advanced Rx of Tennessee, LLC, Advanced Rx Pharmacy of Tennessee, LLC, American Health Packaging, Aurobindo Pharma Limited, AvPAK, BluePoint Laboratories and 19 more
| Company | First approved | Strengths | Rated |
|---|---|---|---|
| Aurobindo Pharma Ltd | December 2005 | 25MG, 50MG, 100MG | AB |
| Granules India Ltd | December 2005 | 25MG, 50MG, 100MG | AB |
| Glenmark Pharmaceuticals Inc USA | January 2006 | 25MG, 50MG, 100MG | AB |
| Invagen Pharmaceuticals Inc | May 2006 | 25MG, 50MG, 100MG | AB |
| Bionpharma Inc | August 2006 | 25MG, 50MG, 100MG | AB |
| Zydus Lifesciences Ltd | October 2006 | 25MG, 50MG, 100MG | AB |
| Unichem Laboratories Ltd | January 2021 | 25MG, 50MG, 100MG | AB |
| Ani Pharmaceuticals Inc discontinued | December 2005 | 25MG, 50MG, 100MG | – |
| Apotex Inc discontinued | December 2005 | 25MG, 50MG, 100MG | – |
| Pharmobedient Consulting LLC discontinued | December 2005 | 25MG, 50MG, 100MG | – |
| Rising Pharma Holding Inc discontinued | December 2005 | 25MG, 50MG, 100MG | – |
| Roxane Laboratories Inc discontinued | December 2005 | 25MG, 50MG, 100MG | – |
| Sun Pharmaceutical Industries Inc discontinued | December 2005 | 25MG, 50MG, 100MG | – |
| Upsher Smith Laboratories LLC discontinued | December 2005 | 25MG, 50MG, 100MG | – |
| Sun Pharmaceutical Industries Ltd discontinued | March 2006 | 25MG, 50MG, 100MG | – |
| Chartwell Rx Sciences LLC discontinued | April 2006 | 25MG, 50MG, 100MG | – |
| Epic Pharma LLC discontinued | February 2007 | 25MG, 50MG, 100MG | – |
| Macleods Pharmaceuticals Ltd discontinued | May 2025 | 25MG, 50MG, 100MG | – |
Sources: how many companies have applied, from court records and company announcements; approved generics from the FDA Orange Book; tentative approvals from Drugs@FDA; what is for sale from the FDA NDC Directory. The FDA does not disclose an application before it approves it (21 CFR 314.430).
Zonisade Price: What Pharmacies Pay and What Generics Usually Do
What Pharmacies Pay for Zonisade 100 mg/5 mL oral susp
$2.75 per mL in October 2026, up 17.2% from a year earlier.
Hover over or tap anywhere on the chart to see that month’s price.
See the numbers
| Month | Pharmacies paid per mL |
|---|---|
| October 2026 | $2.75 |
| September 2026 | $2.75 |
| August 2026 | $2.75 |
| July 2026 | $2.75 |
| June 2026 | $2.75 |
| May 2026 | $2.75 |
| April 2026 | $2.75 |
| March 2026 | $2.75 |
| February 2026 | $2.75 |
| January 2026 | $2.75 |
| February 2024 | $2.35 |
| January 2024 | $2.35 |
NADAC: the national average price retail pharmacies pay to buy the medicine (CMS survey, updated weekly), the last price of each month for one package. It is not what you pay: that depends on your insurance or discount card.
What a Generic Could Cost
How we estimate it. We start from what pharmacies pay for Zonisade today: $2.75 per mL for Zonisade 100 mg/5 mL oral susp in October 2026, from the national NADAC survey. Then we apply the FDA’s finding of how far that price usually falls as generic companies join: about 31% with one company, 44% with two, 73% with four and over 95% with six or more (the typical drop for every drug whose first generic came out from 2015 to 2017). Zonisade has 7 companies lined up, so our estimate uses the figure for six or more companies. More companies would bring the price lower; fewer, less of a drop.
Dollar figures apply FDA’s median drops to the $2.75 pharmacies pay per mL today. An estimate from the pattern, not a price quote: what you pay depends on your insurance or discount card.
Median prices pharmacies paid for the generic (invoice prices), compared with the brand’s price before generic entry, from FDA’s 2019 analysis “Generic Competition and Drug Prices”. At the manufacturer’s price FDA found steeper drops (about 39%, 54%, 79% and over 95%), the figures quoted elsewhere on this tracker. A typical pattern, not a price quote for this medicine.
What Medicare and Medicaid Spend on Zonisade
Big public spending is part of why generic makers line up for a medicine, and why its first generic matters beyond the pharmacy counter. Figures are before manufacturer rebates, which are confidential.
Medicare Part D Spending
What Medicare drug plans spent on Zonisade, before manufacturer rebates.
- $2M
- January to March 2026, the latest CMS has posted
For 513 people, about $1,213 per prescription fill - $6.6M
- 2025, the whole year
For 665 people, about $1,196 per prescription fill
See the numbers
| Period | Spending | People | Per fill |
|---|---|---|---|
| January to March 2026 | $2,037,508 | 513 | $1,212.80 |
| 2025 | $6,628,839 | 665 | $1,196.11 |
Source: CMS Medicare Part D Spending by Drug, matched by the brand name Zonisade only, so no generic is counted in it. What CMS says it is used for: Zonisamide is used with other medications to prevent and control seizures (epilepsy). Zonisamide is a sulfonamide anticonvulsant and a carbonic anhydrase inhibitor.
Medicaid Prescriptions by Quarter
39,564 prescriptions in the four quarters to Q1 2026, $34.9M paid.
See the numbers
| Quarter | Prescriptions | Medicaid paid |
|---|---|---|
| Q1 2026 | 10,211 | $9,329,322 |
| Q4 2025 | 10,163 | $9,009,368 |
| Q3 2025 | 9,856 | $8,572,646 |
| Q2 2025 | 9,334 | $7,945,144 |
| Q1 2025 | 8,773 | $7,272,098 |
Source: CMS Medicaid State Drug Utilization Data, over Zonisade’s own package codes.
Zonisade Strengths and Forms
| Strength | Form | How it is taken | Approved | Status |
|---|---|---|---|---|
| 100MG/5ML | Suspension | Oral | July 2022 | Prescription reference product |
Source: FDA Orange Book, Azurity Pharmaceuticals Inc. Listed for sale today by Azurity Phramaceuticals, Inc. and Azurity Pharmaceuticals, Inc. (FDA NDC Directory).
Zonisade NDC Codes and Packages
Each Zonisade package sold today has its own NDC, the product number printed on the box and on the pharmacy label. Open one to see that package’s details, what pharmacies pay for it and its patent timeline.
| NDC | Product | Package | Company |
|---|---|---|---|
| 52652-8001-01 | ZONISAMIDE 100 mg/5mL suspension | bottle of 150 mL | Azurity Pharmaceuticals, Inc. |
| 52652-8001-01 | ZONISAMIDE 100 mg/5mL suspension | bottle of 150 mL | Azurity Pharmaceuticals, Inc. |
Source: the FDA NDC Directory, current listings only. Only packages sold under Zonisade’s own FDA approval (NDA 214273) are listed, never a generic. Some codes belong to companies that repackage Zonisade: it is the same medicine in a different package.
What a Generic Zonisade Means for You
Nothing Changes Until It Is in Pharmacies
A generic is listed for sale now, so your pharmacy may already be able to fill your prescription with it.
Your Pharmacy May Switch You Automatically
Every state lets pharmacists fill a brand-name prescription with an FDA-approved generic rated as equivalent to it, and about 19 states require them to, unless your prescriber writes “dispense as written” or “brand medically necessary” on the prescription. Some states ask the pharmacist to tell you, or to get your OK first. A study of every state’s law has the details.
It Will Probably Look Different
US trademark law does not let a generic look exactly like the brand, so the color, shape or markings usually change. The active ingredient, strength and form are the same. An “authorized generic,” made by or for the brand’s own company, can look identical. The FDA explains.
Your Insurance May Change Too
Once a lower-cost version is available, many insurance plans charge more for the brand, or stop covering it. Your plan’s drug list (formulary) says how.
Questions people ask about Zonisade
Is there a generic for Zonisade right now?
Yes. The FDA NDC Directory lists a generic zonisamide from 25 companies. Ask your pharmacy whether it can fill your prescription with it.
When will Zonisade go generic?
It already has. The FDA NDC Directory lists a generic zonisamide from 25 companies, so ask your pharmacy whether it can fill your prescription with one.
Will generic zonisamide be the same as Zonisade?
Yes in the ways that matter: the same active ingredient, strength and form, with proof that it reaches your blood the same way. Inactive ingredients can differ, which is why some people notice a different look or taste.
How much will the generic cost?
Nobody can say for sure before launch. At least 7 companies have applied to the FDA to make it. In the FDA’s study of past launches, pharmacies paid over 95% less once six or more companies sold a generic, which would take the $2.75 pharmacies pay per mL for Zonisade today to under $0.14. That is a pattern from past launches, not a prediction for this one.
Has the FDA approved a generic Zonisade?
Yes. The FDA Orange Book lists approved generic versions from 7 companies, the first approved in December 2005: Aurobindo Pharma Ltd, Granules India Ltd, Glenmark Pharmaceuticals Inc USA, Invagen Pharmaceuticals Inc and 3 more. Approved is not the same as on sale: patents, a settlement or the company’s own plans can still hold a launch.
When does the Zonisade patent expire?
The FDA Orange Book lists 4 patents for Zonisade; the last runs to August 2038. A patent date is not the launch date: settlements and court rulings often bring a generic earlier, and FDA approval or a company’s own plans can make it later. The expected month on this page (September 2027) weighs all of that.
Has anyone challenged the Zonisade patents?
Yes. The first patent challenge to Zonisade reached the FDA in February 2025, from one company on that first day. The FDA has not approved a first challenger’s generic yet. A patent challenge (a “Paragraph IV certification”) is a generic company telling the FDA that a patent listed for the brand is invalid or will not be infringed by its version. The first companies to file one can earn a 180-day head start, during which the FDA cannot approve the generics that filed after them.
How much does Zonisade cost now?
Pharmacies paid about $2.75 per mL for Zonisade 100 mg/5 mL oral susp in October 2026, by the national survey of what pharmacies pay (NADAC). That is the pharmacy’s cost, not your price: what you pay depends on your insurance or discount card.
Changes to This Projection
- First generic expected September 2027 on this month’s schedule. A line is added here whenever a monthly update moves the month, the reason or how sure it is.
Every change to the expected month is logged here with the month we saw it.
Also Going Generic
- KalydecoIvacaftorJanuary to June 2028
- StribildCobicistat, Elvitegravir, Emtricitabine, and Tenofovir Disoproxil Fumarate2029 to 2030
- EohiliaBudesonideFebruary 2031
- AurlumynIloprostFebruary 2031
- OrfadinNitisinoneFebruary 2033
- WayrilzRilzabrutinibOctober 2040
About Zonisade
- Generic name zonisamide
- How it is taken By mouth
- Company Azurity Pharmaceuticals Inc
- Patent challenges Since February 2025 (FDA)
- More drugs Brand-name drugs starting with Z
- Have a question? A pharmacist answers, free. Ask about Zonisade
Sources. The expected month: FDA Paragraph IV Patent Certifications list, federal court records, company announcements and securities filings (settlement dates, launch plans, sales). The record on this page: FDA Orange Book, Drugs@FDA (tentative approvals), FDA NDC Directory, FDA Paragraph IV Patent Certifications list, NADAC (CMS), CMS Medicare Part D Spending by Drug, Medicaid State Drug Utilization Data, FDA, Generic Competition and Drug Prices (2019). Updated October 9, 2026. Information, not medical advice.