How to Fill Out FDA Form 3542 (w/Examples) + FAQs

FDA Form 3542 is the official document that brand-name drug companies use to submit patent information to the FDA’s Orange Book after a drug receives approval. Under 21 CFR 314.53, NDA holders must submit this form within 30 days of approval or within 30 days of a patent being issued by the U.S. Patent and Trademark Office. Filing this form correctly matters because it directly affects whether generic drug makers can enter the market and at what price patients pay for medications.

A single improperly listed patent can trigger a 30-month stay on generic drug approval—blocking cheaper alternatives from reaching patients. The FTC has challenged more than 200 patents as improperly listed in the Orange Book, affecting drugs ranging from EpiPens to asthma inhalers. Getting Form 3542 right the first time protects both brand companies and patients.

Here’s what you will learn in this article:

• 📋 How to complete every section of FDA Form 3542, including drug substance, drug product, and method-of-use patent declarations
• ⏰ Critical deadlines and timing requirements that affect whether your patent will be listed in the Orange Book
• ⚖️ Real-world examples from major patent disputes like Prozac and EpiPen that show the stakes involved
• 🚫 Common mistakes to avoid that could result in delisting, litigation, or FTC scrutiny
• ❓ FAQs that answer the most pressing questions about patent certifications, 30-month stays, and 180-day exclusivity

What Is FDA Form 3542?

FDA Form 3542 is a patent declaration form that NDA holders submit to report patent information after a drug receives FDA approval. The FDA uses this information to populate the Orange Book—the official database of approved drugs and their associated patents. Generic drug companies must address every patent listed in the Orange Book before their products can receive approval.

The form serves two primary purposes. First, it notifies the FDA of patents that protect an approved drug’s active ingredient, formulation, or method of use. Second, it creates a legal record that generic applicants must either wait out, design around, or challenge in court.

Form 3542 vs. Form 3542a: Key Differences

Form 3542a accompanies the initial NDA submission and covers patents claiming the proposed drug. Form 3542, by contrast, covers patents claiming the approved drug and must be submitted within 30 days after approval or within 30 days after a patent issues. The FDA publishes information from Form 3542—not Form 3542a—in the Orange Book.

Who Must File Form 3542?

The New Drug Application holder bears sole responsibility for submitting accurate patent information. This applies to any company holding an approved NDA under Section 505 of the Federal Food, Drug, and Cosmetic Act.

If the patent owner differs from the NDA holder, the patent owner may complete certain sections of the form. However, the patent owner may need information from the NDA holder to complete required fields. Both parties must coordinate because incomplete forms will not be accepted.

The FDA’s role is strictly ministerial. The Agency does not substantively review whether a patent actually covers the approved drug. Instead, FDA relies on the NDA holder’s declarations. This places enormous responsibility—and legal liability—on the company submitting the form.

Critical Deadlines: When Must You File?

Missing the 30-day deadline has serious consequences. Under 21 CFR 314.53(c)(2)(ii), patent information submitted more than 30 days after approval or patent issuance is considered “untimely filed.”

The 15-Day Correction Window

If FDA notifies an NDA holder that Form 3542 is incomplete or shows the patent is not eligible for listing, the company has exactly 15 days to submit an acceptable corrected form. Correcting all deficiencies within this window preserves the original filing date. Missing this deadline means the form is considered filed as of the date the corrected form arrives—which may render the filing untimely.

Section-by-Section Guide: How to Complete Form 3542

Form 3542 contains six sections. Each requires specific information, and incomplete responses will cause FDA to reject the submission.

Header Information: Drug Product Details

Before reaching Section 1, you must provide basic information about the approved drug:

Section 1: General Patent Information

Section 1 captures basic patent details. Complete a separate form for each patent you are submitting.

Field 1.a – Patent Number: Enter the U.S. patent number exactly as issued by the USPTO. Use no more than 10 characters. You cannot list multiple patents on one form.

Field 1.b – Issue Date: Enter the date the USPTO issued the patent in MM/DD/YYYY format.

Field 1.c – Expiration Date: Include any patent term extension already granted under 35 U.S.C. 156(e). Do not include pediatric exclusivity—FDA adds that separately in the Orange Book. Patent term extensions can add up to five years to a patent’s life, but the total remaining term after extension cannot exceed 14 years from the approval date.

Field 1.d – Patent Owner(s): Provide complete contact information for each patent owner. If the patent has multiple owners, click “Add section 1.d” for each additional owner. This information allows generic applicants to send paragraph IV certification notices to the correct parties.

Field 1.e – NDA Holder Information: Provide complete contact information for the NDA holder, even if the same as the patent owner.

Field 1.f – U.S. Agent: Required only if the NDA holder or patent owner does not reside or maintain a business in the United States. Mark whether the agent represents the patent owner, NDA holder, or both.

Field 1.g – Previously Submitted?: Indicate whether this patent has been submitted before for listing in the Orange Book for this drug product.

Field 1.h – Changes from Prior Submission: If answering “yes” to 1.g, describe all changes. Specify whether each change relates to:

• The patent (e.g., term extension, court decision)
• FDA action (e.g., supplement approval changing conditions of use)
• FDA procedure (e.g., response to patent listing dispute)

For method-of-use patents, indicate whether you intend to add a new use code, remove an existing use code, or modify an existing use code. FDA treats removal or modification as a delist of patent information.

Section 2: Drug Substance (Active Ingredient) Patents

Complete Section 2 if the patent claims the drug substance—the active ingredient itself. If you complete Section 2, you do not need to complete Section 3 even if the patent also claims the drug product.

Field 2.1: Does the patent claim the drug substance as approved in the NDA? If “yes,” skip to Field 2.5.

Field 2.2: If “no” to 2.1, does the patent claim a drug substance that is the same as the active ingredient approved in the NDA?

Field 2.3: If “yes” to 2.2, is the drug substance claimed in the patent a polymorph?

Field 2.4: If “yes” to 2.3, you must certify that you have test data demonstrating a drug product containing the polymorph will perform the same as the drug product described in the NDA. This is a critical requirement—polymorph patents without supporting data will not be listed.

Field 2.5: Does the patent claim only a metabolite of the approved active ingredient? If yes, the patent will not be listed as a drug substance patent. However, it may qualify as a method-of-use patent if Section 4 criteria are met.

Field 2.6: Does the patent claim only an intermediate? Patents claiming only intermediates will not be listed.

Field 2.7: Answer any additional questions as appropriate.

Section 3: Drug Product (Formulation/Composition) Patents

Complete Section 3 if the patent claims the drug product—its formulation or composition. If you completed Section 2 for this patent, skip Section 3 entirely.

Drug product patents cover how the drug is made, not what it is. These include patents on:

• Specific formulations
• Compositions of matter
• Extended-release mechanisms
• Combination products
• Delivery systems

Field 3.2: Does the patent claim only an intermediate? If yes, the patent will not be listed.

Field 3.3: Answer additional questions as appropriate to confirm the patent claims the approved drug product.

Section 4: Method-of-Use Patents

Method-of-use patents are among the most contested in pharmaceutical litigation. These patents cover indications or other conditions of use for which the drug has been approved.

Field 4.1: Does the patent claim one or more approved methods of using the drug product? If the patent claims multiple methods of use, complete a separate set of 4.2 fields for each.

Field 4.2 – Patent Claims: List the specific patent claim numbers that cover each approved method of use. Use commas to separate multiple claim numbers. For example: “claims 1, 2, 3” for the first method of use.

Field 4.2a – Labeling Reference: Identify the specific labeling sections describing the patented method of use. Format requirements vary by drug type:

Field 4.2b – Use Code: This is the description published in the Orange Book. The use code must:

• Describe only the specific approved method of use claimed by the patent
• Not extend beyond the scope of the patent claims
• Contain adequate information to help generic applicants determine if their product would infringe
• Use a maximum of 250 characters

The use code’s scope is critical. If the patented method is narrower than an approved indication, describe only the specific patented method—not the broader indication. Overbroad use codes have been challenged by the FTC and can trigger patent listing disputes.

Section 5: No Relevant Patents

Complete Section 5 only if there are no relevant patents for the NDA or supplement. Leave Sections 1–4 blank and check the appropriate box. This declaration is still required—even when no patents exist.

Section 6: Declaration Certification

This section contains the legally binding certification. The person signing attests under penalty of perjury that:

• The submission is accurate and complete
• The patent meets statutory requirements for listing
• The submission complies with 21 CFR 314.53

Field 6.2: Date and sign the form. Indicate whether the signatory is:

• The NDA holder
• An attorney or agent for the NDA holder
• The patent owner
• An attorney or agent for the patent owner

Field 6.3: If the person signing in 6.2 is located outside the United States, a U.S.-based attorney, agent, or authorized official must countersign.

The perjury declaration is not symbolic. The FTC has warned companies that submitting or maintaining improper patent listings may violate the FTC Act and result in legal liability.

How Generic Companies Use Form 3542 Information

Understanding Form 3542 requires understanding how generic companies respond to it. When a generic company files an ANDA, it must certify to every patent listed in the Orange Book for the reference drug.

The Four Paragraph Certifications

Paragraph IV certifications are the most contentious. Filing one is considered an “artificial act of infringement” under Hatch-Waxman. The generic applicant must notify the NDA holder and patent owner within 20 days of FDA acknowledgment. If the brand company sues within 45 days of receiving notice, FDA automatically stays approval for up to 30 months while litigation proceeds.

Real-World Example: Prozac and Barr Laboratories

The Prozac case demonstrates how Form 3542 filings shape billion-dollar markets.

In 1995, Barr Laboratories filed an ANDA with a Paragraph IV certification for fluoxetine hydrochloride—Prozac’s active ingredient. Barr claimed Eli Lilly’s patents were either invalid or would not be infringed. Lilly sued, triggering litigation that reached the Federal Circuit.

This case illustrates why accurate Form 3542 filings matter. Had Lilly’s patent information been challenged earlier or found improperly listed, the market entry timeline could have shifted dramatically.

Skinny Labels and Section VIII Carve-Outs

Not all generic products need to address every method-of-use patent. When a drug substance patent has expired but method-of-use patents remain active, generic companies can use Section VIII statements to “carve out” the patented uses from their labeling.

The result is a “skinny label”—a label that omits patented indications while including non-patented uses. This allows generics to enter the market years earlier than if they waited for all patents to expire.

Skinny labels work because pharmacists can legally substitute the generic for any use, even those carved out. A 2021 study found that skinny labels trimmed an average of 3.2 years of exclusivity from brand drugs.

Patent Delisting: How Patents Are Removed

NDA holders can request removal of patents from the Orange Book by submitting a delisting request letter. However, the patent will not be fully removed if a generic applicant is eligible for 180-day exclusivity based on a Paragraph IV certification to that patent.

When a patent cannot be fully removed, the Orange Book displays a “Delist Requested” flag. The patent remains listed until exclusivity expires, is extinguished, or is relinquished.

Court-Ordered Delisting

If a court finds a patent invalid or unenforceable, the NDA holder must:

1. Promptly notify FDA to amend or withdraw the patent information
2. Submit an amendment to the NDA within 14 days of the court order
3. Include a copy of the court order with the submission

Mistakes to Avoid When Filing Form 3542

Do’s and Don’ts for Form 3542

Do’s ✅

Don’ts ❌

Pros and Cons of Orange Book Patent Listing

Pros for NDA Holders

Cons and Risks

Frequently Asked Questions

Can I submit Form 3542 before my NDA is approved?
No. Form 3542 is only for approved drugs. Use Form 3542a for patent information submitted with an original NDA, amendment, or supplement before approval.

What happens if I miss the 30-day filing deadline?
Yes, there are consequences. The patent will be considered untimely filed and generic applicants will not trigger a 30-month stay by filing Paragraph IV certifications to that patent.

Must I list a patent that I believe does not cover my drug?
No. You should only list patents that meet the statutory requirements. However, intentionally failing to list a qualifying patent violates FDA regulations.

Can the FDA delist my patent without my consent?
No. FDA relies on NDA holder certifications. However, FDA will forward listing disputes and the NDA holder must respond within 30 days.

Does listing a patent guarantee I will win infringement litigation?
No. Listing only ensures generic applicants must certify to the patent. A court may still find the patent invalid or not infringed.

Can I update my use code after initial submission?
Yes. Use codes may be amended within 30 days of labeling changes, court decisions altering claim construction, or USPTO determinations. Submit updated information on Form 3542.

What if multiple companies own the same patent?
Yes, this is allowed. List all patent owners in Field 1.d. Click “Add section 1.d” for each additional owner. All owners receive Paragraph IV certification notices.

Is electronic submission required?
No, but recommended. FDA accepts electronic submissions that comply with 21 CFR 314.50. Include “Form 3542” in the file name for automated processing.

Can generic companies challenge my use code?
Yes. Any person may initiate a patent listing dispute under 21 CFR 314.53(f)(1) by notifying FDA in writing.

Does the 30-month stay apply to all patents I list?
No. The stay only applies to patents listed before a generic application was submitted. Late-listed patents do not receive this protection.