ROBAXIN Drug Patent Profile

Which patents cover Robaxin, and when can generic versions of Robaxin launch?

Robaxin is a drug marketed by Hikma and Endo Operations and is included in two NDAs.

The generic ingredient in ROBAXIN is methocarbamol. There is one drug master file entry for this compound. Sixty-eight suppliers are listed for this compound. Additional details are available on the methocarbamol profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Robaxin

A generic version of ROBAXIN was approved as methocarbamol by REGCON HOLDINGS on July 21^st, 2017.

Summary for ROBAXIN

US Patents:	0
Applicants:	2
NDAs:	2
Finished Product Suppliers / Packagers:	1
Raw Ingredient (Bulk) Api Vendors:	1
Clinical Trials:	2
Patent Applications:	4,106
Drug Prices:	Drug price information for ROBAXIN
What excipients (inactive ingredients) are in ROBAXIN?	ROBAXIN excipients list
DailyMed Link:	ROBAXIN at DailyMed

See drug prices for ROBAXIN

Recent Clinical Trials for ROBAXIN

Identify potential brand extensions & 505(b)(2) entrants

Sponsor	Phase
Mayo Clinic	Phase 4
Medical College of Wisconsin	Phase 4

See all ROBAXIN clinical trials

Pharmacology for ROBAXIN

Drug Class	Muscle Relaxant
Physiological Effect	Centrally-mediated Muscle Relaxation

US Patents and Regulatory Information for ROBAXIN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Hikma	ROBAXIN	methocarbamol	SOLUTION;IM-IV	011790-001	Approved Prior to Jan 1, 1982	AP	RX	Yes	Yes
Endo Operations	ROBAXIN	methocarbamol	TABLET;ORAL	011011-004	Approved Prior to Jan 1, 1982		DISCN	Yes	No
Endo Operations	ROBAXIN-750	methocarbamol	TABLET;ORAL	011011-006	Approved Prior to Jan 1, 1982		DISCN	Yes	No

Robaxin Market Dynamics and Financial Trajectory: Methocarbamol Sales, Competition, Patents, and Generic Risk

Last updated: September 25, 2026

Robaxin is the branded formulation of methocarbamol, a centrally acting skeletal-muscle relaxant used with rest and physical therapy for acute, painful musculoskeletal conditions. Its commercial profile is mature and largely genericized. The drug has limited patent protection, no meaningful biologic or biosimilar exposure, and low barriers to generic substitution. Public companies do not generally report Robaxin revenue separately, so the product’s precise sales trajectory cannot be verified from issuer filings. The economic opportunity is concentrated in generic volume, hospital injectable supply, private-label distribution, and pricing rather than in branded innovation.

What is Robaxin and how is methocarbamol used?

Robaxin contains methocarbamol. U.S. labeling covers oral tablets and an injectable formulation. The product is indicated as an adjunct to rest, physical therapy, and other measures for acute, painful musculoskeletal conditions. The label does not establish a role for chronic neurologic spasticity or long-term pain treatment. [1]

Which formulations does Robaxin have?

Formulation	Typical commercial role	Competitive exposure
Methocarbamol tablets	Outpatient treatment	High generic substitution
Methocarbamol injection	Hospital, emergency, and acute-care use	Lower supplier count than tablets, but still generic
Robaxin branded tablets	Residual brand demand and prescribing familiarity	Limited pricing power
Robaxin injectable product	Institutional and acute-care demand	Vulnerable to contract pricing and shortages

Robaxin tablets are commonly marketed in 500 mg and 750 mg strengths. Methocarbamol injection is supplied for intramuscular or intravenous administration under prescribing and institutional-use restrictions. Product availability varies by manufacturer, wholesaler, and dosage form. [1,2]

How large is the Robaxin and methocarbamol market?

The U.S. market is a mature, high-volume generic segment rather than a premium branded market. Methocarbamol competes with cyclobenzaprine, tizanidine, baclofen, carisoprodol, metaxalone, and nonprescription pain-treatment strategies. Prescribing depends on acute musculoskeletal injury rates, primary-care and emergency-department utilization, workers’ compensation claims, orthopedic procedures, and insurer formulary rules.

Reliable public sources do not provide a standalone global Robaxin revenue figure. Manufacturers generally aggregate methocarbamol sales with broader generic portfolios, and claims databases report prescription volume rather than manufacturer-level net sales. The absence of disclosed product revenue is consistent with a low-growth, multi-supplier generic product.

What drives methocarbamol demand?

The main demand variables are:

• Acute back pain, muscle strain, sprain, and other musculoskeletal conditions.
• Emergency-department and urgent-care prescribing.
• Generic formulary placement.
• Hospital demand for injectable muscle relaxants.
• Prescriber preference for methocarbamol relative to sedating alternatives.
• State and payer controls on controlled or abuse-prone muscle relaxants.

Methocarbamol benefits from its long prescribing history and broad generic availability. It faces volume pressure from treatment-duration limits, safety concerns involving central nervous system depression, and clinical preference for nonpharmacologic treatment or other agents.

What is the financial trajectory for Robaxin?

Robaxin’s financial trajectory is best characterized as mature and declining in brand economics, with relatively stable or modestly expanding generic demand. The product has passed the period in which exclusivity, launch pricing, or patent extensions could support rapid revenue growth.

Brand economics

The original Robaxin brand had commercial value when methocarbamol was protected by legacy product and formulation rights. That value diminished after generic methocarbamol became widely available. Current brand economics are constrained by:

1. Therapeutic interchangeability.
2. Pharmacy benefit manager substitution.
3. Low switching costs for prescribers.
4. Multiple tablet suppliers.
5. Limited clinical differentiation.
6. Low patient willingness to pay for the brand.

Any remaining branded revenue is likely to come from brand-loyal prescribing, institutional purchasing, supply continuity, and distribution agreements rather than a patent-backed premium.

Generic economics

Generic methocarbamol revenue depends on prescription volume and average selling price. Tablet products usually face substantial price competition. Injectable products can produce better economics when supply is concentrated, manufacturing is difficult, or temporary shortages affect competitors. Those advantages are episodic and can reverse when additional suppliers enter.

A generic manufacturer with an established hospital-sales channel can earn more durable value from injection than from standard tablets. The key commercial assets are regulatory approvals, manufacturing reliability, inventory availability, wholesaler access, and institutional contracts.

When does Robaxin lose exclusivity?

Robaxin’s core U.S. exclusivity period expired decades ago. Methocarbamol is an old small-molecule product, and generic versions have long been available. The product does not have a current data-exclusivity profile comparable to a new chemical entity.

Exclusivity category	Robaxin status
New chemical entity exclusivity	Expired
Orphan-drug exclusivity	None identified
Pediatric exclusivity	No material current protection identified
Core compound patent protection	Expired
Current branded market exclusivity	None identified
Generic competition	Established

The relevant commercial question is therefore not when exclusivity ends. It is how many approved suppliers remain active, whether the product appears on payer formularies, and whether manufacturers can maintain reliable supply.

What patents protect Robaxin and methocarbamol?

The original compound and early Robaxin rights are historic. No active U.S. patent estate is generally associated with the basic methocarbamol molecule as a barrier to ordinary generic tablets.

Are formulation patents still important?

Formulation patents could matter for modified-release products, delivery systems, or other differentiated presentations. Standard immediate-release methocarbamol tablets do not have a meaningful current formulation barrier comparable to extended-release products in protected markets.

Potential intellectual-property issues may still arise around:

• Tablet composition.
• Manufacturing processes.
• Injectable formulation parameters.
• Packaging and stability.
• Trade dress and trademarks.
• Country-specific registrations.

These rights are narrower than a compound patent and usually do not prevent approval of a conventional generic product that uses a different formulation or process.

What is the Orange Book status of Robaxin?

FDA Orange Book analysis should distinguish the listed drug from active patents. A drug may remain listed as a reference product even when its core patent protection has expired. Robaxin and methocarbamol products have long been subject to generic approval pathways under abbreviated new drug applications. [3]

The commercial relevance of an Orange Book listing is therefore limited unless an active patent is listed against a specific reference product. For mature methocarbamol products, generic manufacturers generally compete without confronting a modern blocking patent estate.

Which companies compete with Robaxin?

Competition exists at both the manufacturer and therapeutic levels.

Manufacturer competition

Methocarbamol products have been supplied by multiple generic pharmaceutical companies and private-label distributors. Depending on product and period, U.S. supply has included manufacturers such as Hikma, Amneal, Solco Healthcare, Camber, Rising Pharmaceuticals, and other approved suppliers. Exact active-market participation changes as companies discontinue products, transfer approvals, or alter distribution arrangements.

Brand and authorized-generic rights can also change through licensing or asset transactions. Public reporting does not establish a stable, current standalone Robaxin revenue owner across all U.S. dosage forms.

Therapeutic competition

Competitor	Active ingredient	Main commercial distinction
Flexeril and generic cyclobenzaprine	Cyclobenzaprine	Large historical generic base
Zanaflex and generic tizanidine	Tizanidine	Used for spasticity and muscle tightness
Lioresal and generic baclofen	Baclofen	Stronger association with neurologic spasticity
Soma and generic carisoprodol	Carisoprodol	Controlled-substance and abuse-risk considerations
Skelaxin and generic metaxalone	Metaxalone	Competes in acute musculoskeletal treatment
Robaxin and generic methocarbamol	Methocarbamol	Established acute-care and outpatient use

Methocarbamol’s competitive position benefits from avoidance of controlled-substance classification in the United States. It remains exposed to sedation, dizziness, impaired coordination, and additive central nervous system depression. [1]

Are there Paragraph IV challenges to Robaxin?

Paragraph IV litigation is not a central current risk for ordinary methocarbamol tablets because the foundational patents have expired and the market has long contained generics. ANDA applicants may still make patent certifications where listed patents exist, but there is no widely recognized current Paragraph IV dispute that threatens the overall methocarbamol market.

The litigation risk profile is more likely to involve:

• Product liability claims.
• Manufacturing or quality disputes.
• Contract and supply litigation.
• Trademark or trade-dress issues.
• Patent disputes involving a new formulation or delivery system.

A new branded methocarbamol formulation could create a different patent and litigation profile, but the conventional product has a low current patent risk.

What FDA regulatory issues affect Robaxin?

Methocarbamol is regulated as an approved prescription drug. The main FDA-related commercial risks are manufacturing compliance, drug shortages, labeling, postmarketing safety, and product discontinuation.

FDA pathway

Generic oral methocarbamol products are generally approved through the ANDA pathway. The applicant must demonstrate pharmaceutical equivalence and bioequivalence to the reference listed drug. Injectable products face additional chemistry, manufacturing, controls, sterility, and facility requirements. [3]

Safety and labeling

The label warns about central nervous system effects and impairment. Alcohol, opioids, benzodiazepines, sedating antihistamines, and other central nervous system depressants can increase risk. These limitations restrict some prescribing but also support continued use where clinicians seek a noncontrolled muscle relaxant. [1]

What generic entry risks exist for Robaxin?

Generic entry is no longer a future event for Robaxin. It is the defining market condition.

Tablet-entry risk

Tablet suppliers face:

• Rapid price erosion after approval.
• Retail pharmacy substitution.
• Formulary pressure.
• Low differentiation.
• Inventory and wholesaler competition.
• Contract losses when large buyers consolidate volume.

A new tablet entrant can gain volume but may not sustain attractive margins unless it has a cost advantage, a supply agreement, or a differentiated distribution channel.

Injectable-entry risk

Injectable methocarbamol has higher operational barriers because sterile manufacturing is more complex than tablet production. Those barriers reduce the number of reliable suppliers and can support better pricing. They do not create durable monopoly economics. A new approved injectable supplier can weaken incumbent pricing, particularly if it has excess capacity and institutional contracting access.

How strong is the Robaxin patent estate?

The patent estate is weak as a current commercial defense.

Factor	Assessment
Compound protection	Expired
Core formulation protection	Limited or expired for conventional products
Orange Book barrier	Low
Paragraph IV exposure	Low current significance
Manufacturing barrier	Moderate for injection; low to moderate for tablets
Brand differentiation	Low
Generic substitution risk	High
Biosimilar risk	Not applicable

The most defensible assets are operational rather than patent-based: reliable sterile manufacturing, regulatory compliance, supply continuity, and purchasing relationships.

Does Robaxin face biosimilar competition?

No. Robaxin is a small-molecule drug, not a biologic. Biosimilar pathways do not apply. Competition occurs through generic drug approval and substitution, primarily under the ANDA framework.

Are there licensing deals affecting Robaxin?

Robaxin’s commercial history includes changes in brand ownership, marketing rights, and generic distribution. Public company disclosures do not provide a consistent standalone accounting trail for all Robaxin rights, dosage forms, and geographic markets. Any transaction analysis should distinguish:

• U.S. brand rights.
• Authorized-generic rights.
• Injectable rights.
• Tablet approvals.
• Manufacturing rights.
• Distribution rights.
• Non-U.S. registrations.

Rights can be split across entities, making a simple “Robaxin owner” designation unreliable without product-specific transaction documents.

What geographic markets are relevant to Robaxin?

The United States is the most commercially visible market because of FDA approvals, Orange Book records, generic substitution, and public payer data. International markets vary in:

• Brand ownership.
• Methocarbamol availability.
• Prescription status.
• Reimbursement.
• Local manufacturing.
• Trademark rights.
• Regulatory classification.

A company with a U.S. approval may have no corresponding European, Canadian, or emerging-market right. Geographic revenue cannot be inferred from U.S. product availability.

What generic launch scenarios are most likely?

Base case

Existing generic suppliers retain most volume while prices remain competitive. Brand revenue stays limited, and manufacturer profitability depends on cost control and supply reliability.

Upside case

A shortage, plant disruption, or supplier exit improves pricing for injectable methocarbamol. The benefit is temporary unless the manufacturer maintains a structural capacity or regulatory advantage.

Downside case

Additional tablet suppliers enter, payer pressure intensifies, or a large buyer consolidates contracts. Unit prices and gross margins decline.

Key Takeaways

• Robaxin is a mature methocarbamol product with long-expired core exclusivity.
• Generic competition, not patent protection, controls market economics.
• Public filings do not provide a reliable standalone Robaxin revenue series.
• Tablet methocarbamol has high substitution and price-erosion risk.
• Injectable methocarbamol has higher manufacturing barriers and potentially better margins.
• The product has no biosimilar risk because it is a small molecule.
• Current value lies in supply reliability, sterile manufacturing, regulatory approvals, and distribution contracts.
• Paragraph IV and Orange Book patent risks are low for conventional methocarbamol products.
• The financial trajectory is mature, volume-driven, and vulnerable to generic price competition.

FAQs

Is Robaxin still a profitable drug?

It can be profitable for efficient generic manufacturers, particularly in injectable form, but it is unlikely to support large branded margins. Profitability depends on manufacturing cost, contract access, supplier concentration, and temporary supply disruptions.

Is methocarbamol a controlled substance?

Methocarbamol is not federally classified as a controlled substance in the United States. It can still cause sedation and impairment, especially when combined with alcohol or other central nervous system depressants. [1]

Can a generic company launch methocarbamol without a patent license?

For a conventional product with no blocking unexpired patent, a generic applicant can generally pursue FDA approval through the ANDA pathway without obtaining a license from the historical brand owner. Product-specific Orange Book records and patent certifications remain relevant. [3]

Does Robaxin have extended-release patent protection?

Conventional Robaxin tablets are not generally protected by a current extended-release patent estate. A separately developed modified-release formulation could have its own patents and regulatory exclusivity.

What is the biggest commercial risk for a Robaxin manufacturer?

The largest risk is margin compression caused by additional generic supply, payer and wholesaler bargaining power, or loss of manufacturing reliability. For injectable products, facility compliance and sterile-supply interruptions are especially important.

References

1. U.S. Food and Drug Administration. (2023). Robaxin-750 (methocarbamol) tablets: Prescribing information.
2. National Library of Medicine. (2024). DailyMed: Methocarbamol and Robaxin product labeling.
3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.

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