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Orange Book drug · Brand (NDA)

Skelaxin

Metaxalone

DiscontinuedRLDNDA 013217 2 strengths King Pharms
Approved
Prior to Jan 1, 1982
Strengths
2
Listed patents
1

What does the FDA Orange Book show for Skelaxin?

Skelaxin contains Metaxalone and is the new drug FDA Orange Book record for NDA 013217. The application has 2 presentations with strength, dosage-form, route, status, RLD/RS, TE, patent, and exclusivity context. Current inventory and clinical labeling are not established without an application-matched source.

FDA application
NDA 013217

New drug application identity from the Orange Book snapshot.

Application holder
King Pharmaceuticals Research And Development LLC A Sub Of Pfizer Inc

The listed applicant holds the FDA application; this field does not establish the product manufacturer.

Product presentations
2

Each FDA product number remains tied to its own strength, dosage form, route, and status.

Marketing categories
Discontinued

Orange Book marketing categories do not establish real-time inventory or commercial availability.

Reference roles
RLD

RLD and RS designations are presentation-specific, not inferred from the trade name.

TE codes
None posted

Therapeutic-equivalence codes apply only within the matching Orange Book product heading.

Listed patents
1

A zero means none appear in this snapshot, not that no patent rights exist.

Exclusivity records
0

FDA exclusivity and listed patent protection are distinct regulatory concepts.

Sourced from the official FDA Orange Book data file · snapshot refreshed

FDA product-presentation matrix

Every product number in this exact application
Every FDA product presentation under this application, with strength, dosage form and route, marketing status, therapeutic-equivalence code, and reference role.
ProductStrengthDosage form / routeMarketing statusTE codeReference role
001400MGTABLETORALDiscontinuedNone posted
RLD
003800MGTABLETORALDiscontinuedNone posted
RLD

Marketing status, TE code, RLD, and RS are presentation-level fields. Never transfer one product number's designation to another presentation.

Who is responsible for this application?

Application holder is not the same as manufacturer

FDA application holder

King Pharmaceuticals Research And Development LLC A Sub Of Pfizer Inc

The Orange Book identifies this organization as the applicant responsible for NDA 013217.

Manufacturer status

Not established by the Orange Book

A product-specific FDA label or NDC source must independently identify a manufacturer, labeler, distributor, packager, repackager, or relabeler. The applicant name is not used as a substitute for that evidence.

Regulatory interpretation

What the record means, and what it does not
FDA marketing status

2 presentations listed as on the Discontinued Drug Product List

A discontinued-list entry does not, by itself, show why marketing stopped or whether FDA determined the product was withdrawn for safety or effectiveness.

Therapeutic equivalence

No TE code is posted for this application

No TE code does not mean FDA found the product ineffective or non-equivalent. FDA generally publishes TE evaluations for multisource prescription products; single-source and some other products may have no code.

Patent & exclusivity record

No future patent-expiry or exclusivity dates are recorded

The snapshot contains 1 listed patent and 0 exclusivity records, but none has a date on or after Jul 26, 2026. This is not a legal conclusion that the product is unprotected.

Same-ingredient landscape

8 other ANDAs and 1 other NDA found

6 of the related ANDA applications are not marked discontinued. Sharing an ingredient does not establish pharmaceutical or therapeutic equivalence; strength, dosage form, route, and TE group still matter.

Which products are meaningfully comparable?

Exact ingredient + dosage form + route cohorts

NDA 013217 appears in 1 comparison cohort. These groups narrow the same-ingredient landscape, but strength and TE code must still match before interpreting therapeutic equivalence.

Why are clinical sections unavailable?

Exact application-label matching status
Exact source match queuedQueue NDA-013217

No exact application-level FDA or DailyMed label match has been reviewed for this application. Approved uses, dosing, warnings, adverse reactions, and clinical evidence remain unavailable rather than being inherited from a related brand, generic, or ingredient record.

Until an exact application match passes human review, this page intentionally omits approved uses, dosing, warnings, adverse reactions, mechanism, and clinical-study summaries. It never inherits those claims from an RLD, brand, generic, or same-ingredient product.

Strengths & dosage forms

2 approved presentations · NDA 013217
RLDDiscontinued
Strength
400MG
Dosage form
TABLET
Route
ORAL
Marketing status
Discontinued

Key dates

Approval, patents, exclusivity

No patent or exclusivity dates are listed for this product.

Pharmaceutical detail

FDA product record

Active ingredient

METAXALONE

Strength

400MG

Dosage form

TABLET

Route

ORAL

TE code

Not listed

Application

NDA 013217

Product number

001

Marketing status

Discontinued

Reference listed drug (RLD)

Yes

Reference standard (RS)

No

Listed patents

Orange Book patent file

No patents are listed against this product in the Orange Book. Listed patents reflect those the NDA holder submits under 21 U.S.C. 355 and are not exhaustive.

Active-ingredient family

Brand + generics

This is a reference-listed drug (RLD), the basis for generic (ANDA) applications. Other products sharing this ingredient are listed below.

View full Metaxalone family

How to use this record responsibly

Scope, limitations, and primary sources

What to verify before making a decision

  • The applicant is the holder of legal responsibility for the application; the Orange Book does not establish that the applicant manufactured or currently markets every listed product.
  • RX, OTC, and discontinued are FDA listing categories, not real-time pharmacy inventory or commercial-availability data.
  • Therapeutic equivalence applies only within the matching ingredient, dosage form, route, strength, and TE-code group; same ingredient alone is insufficient.
  • Listed patent and exclusivity dates are regulatory intelligence, not legal advice, a freedom-to-operate analysis, or a reliable generic-launch forecast.
  • The Orange Book is not prescribing information and does not provide indications, dosing, contraindications, adverse reactions, recalls, or current safety communications.

Official FDA references

Data shown here is normalized for search and comparison. When a regulatory, substitution, launch, or legal decision turns on a field, verify it against the current FDA record and the relevant source document.

Skelaxin: frequently asked questions

Approval, therapeutic equivalence, patents, and exclusivity for this drug, from the FDA Orange Book.

Built directly from the FDA Orange Book product, patent, and exclusivity files refreshed Jul 02, 2026, 06:34 PM. Every strength of NDA 013217 is shown on this page. Interpret patents, exclusivity, availability, and therapeutic equivalence using the limitations above.

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