US Patent 10,383,834: Claim Scope, Expiration, Orange Book Position, and Generic Entry Risk for Intravenous Acetaminophen

US Patent 10,383,834 protects a narrow dosing method for intravenous acetaminophen in adults weighing at least 50 kg. The core regimen is approximately 650 mg administered every four hours, with a total daily dose below 4,000 mg. The patent covers treatment of both pain and fever, plus administration parameters such as infusion time, sterile-solution presentation, and reconstituted lyophilized powder.

The claims do not broadly protect acetaminophen, intravenous acetaminophen as a composition, or every use of the Ofirmev formulation. They target a specific dosing schedule and patient-weight threshold. The principal commercial risk is therefore tied to generic labeling, hospital administration protocols, and induced-infringement theories rather than simple possession or sale of an intravenous acetaminophen product.

What does US Patent 10,383,834 protect?

US Patent 10,383,834 claims methods of treating pain or fever by administering approximately 650 mg of intravenous acetaminophen every four hours to a human subject weighing at least 50 kg, while keeping the daily dose below 4,000 mg.[1]

The independent claims are:

Claim	Protected subject matter	Required limitations
1	Treatment of pain	Human, at least 50 kg; IV acetaminophen; approximately 650 mg; repeat every four hours; daily dose below 4,000 mg
8	Treatment of fever	Same dosing and patient requirements as claim 1, with fever replacing pain

Dependent claims add narrower limitations:

Claims	Limitation
2, 9	Formulation is a sterile solution
3, 10	Administration occurs over approximately 5 to 30 minutes
4, 11	Administration occurs over approximately 15 minutes
5	Patient has acute pain
6	Patient has postoperative pain
7, 12	Formulation is a lyophilized powder reconstituted before administration

The patent is therefore a method-of-use patent with formulation and administration limitations layered onto the principal dosing regimen.

How should the independent claims be construed?

Patient weight requirement

The patient must weigh at least 50 kg. A patient below 50 kg falls outside the literal scope of claims 1 and 8, even if the patient receives 650 mg every four hours.

This limitation is commercially significant because intravenous acetaminophen labeling commonly separates dosing for patients weighing at least 50 kg from dosing for patients weighing less than 50 kg. Hospitals generally record patient weight, making this element relatively easy to establish in a clinical-use case.

Approximately 650 mg

The phrase “about 650 mg” introduces a claim-construction issue. It is not necessarily limited to exactly 650 mg, but the permissible range would depend on the intrinsic evidence, prosecution history, specification, and expert testimony.

A 1,000 mg dose is materially different from the claimed approximately 650 mg dose. A product administered at 650 mg, or a labeled regimen that instructs users to administer a 650 mg dose, presents the clearest literal infringement risk.

Every four hours

The repeated administration requirement is central. A single 650 mg dose does not satisfy the full regimen in claim 1 or claim 8. A six-hour dosing schedule is also outside the literal language of “repeating ... every four hours,” although the doctrine of equivalents could become relevant in litigation.

The phrase is most naturally read as a regimen of approximately six doses per 24 hours. Six 650 mg doses equal 3,900 mg, which satisfies the separate requirement that the patient receive less than 4,000 mg per day.

Daily dose below 4,000 mg

The “less than 4000 mg” limitation excludes a daily dose of exactly 4,000 mg. A regimen of 650 mg every four hours produces 3,900 mg over six administrations and therefore fits the claim.

This limitation distinguishes the patented method from a 1,000 mg every six-hour regimen, which produces 4,000 mg per day. It also creates a potential noninfringement position for regimens that use a lower frequency, a lower dose, or an explicit daily maximum of 3,000 mg.

Intravenous acetaminophen formulation

The formulation must be administered intravenously. Oral, rectal, intramuscular, subcutaneous, and other nonintravenous routes do not satisfy the claims.

The claims do not require a particular concentration, excipient system, container, pH, preservative profile, or manufacturing process. The formulation limitation is functional and route-based rather than a detailed composition limitation.

What formulations are protected by US Patent 10,383,834?

The patent reaches two formulation presentations through dependent claims:

A sterile intravenous solution.
A lyophilized powder that is reconstituted before administration.

The sterile-solution claims are broad at the formulation level. They do not appear to require a specific formulation recipe. A generic intravenous acetaminophen solution could therefore fall within claims 2 or 9 if it is administered under the claimed dosing regimen.

The lyophilized-powder claims are narrower. They require both the dosage regimen and a product supplied as a powder that is reconstituted before administration. A ready-to-use solution would not meet the lyophilized-powder limitation, although it could still fall within claim 1 or claim 8.

Formulation claim strength

The formulation-dependent claims provide limited additional differentiation because the independent claims already require an intravenous acetaminophen formulation. Sterility and reconstitution status narrow the claims, but they do not create a detailed composition patent.

The strongest protection remains in claims 1 and 8. Those claims do not depend on a particular proprietary excipient or manufacturing technique and can read on multiple commercial formulations.

How do the pain and fever claims compare?

Claims 1 and 8 are structurally almost identical.

Issue	Claim 1	Claim 8
Therapeutic use	Pain	Fever
Patient	Human weighing at least 50 kg	Human weighing at least 50 kg
Dose	Approximately 650 mg	Approximately 650 mg
Frequency	Every four hours	Every four hours
Daily limit	Less than 4,000 mg	Less than 4,000 mg
IV route	Required	Required
Dependent formulation claims	Claims 2-7	Claims 9-12

The pain claims are further narrowed by claims directed to acute pain and postoperative pain. The fever claim has no corresponding postoperative limitation in the supplied claim set.

For infringement purposes, a product label that recommends the regimen for both pain and fever presents risk under both independent claims. A label limited to fever may still implicate claim 8 even if it omits pain indications.

When does US Patent 10,383,834 lose exclusivity?

The patent’s base statutory term is tied to the earliest effective nonprovisional filing in its continuation family. The relevant family is associated with an April 2010 nonprovisional filing and earlier priority claims concerning intravenous acetaminophen dosing.[1]

On that basis, the base patent term would ordinarily run to approximately April 2030, subject to any patent-term adjustment or other term calculation reflected in the USPTO record. The issue date, August 20, 2019, does not determine the expiration date.

Event	Date or period
Earliest disclosed family priority	2009 priority chain
Relevant nonprovisional filing period	April 2010
Patent issued	August 20, 2019
Base 20-year term	Approximately April 2030
Potential adjustment	Must be included if awarded by the USPTO

Expiration of this patent would not necessarily eliminate all intellectual-property barriers for intravenous acetaminophen. Separate formulation, manufacturing, pediatric, or method-of-use patents could have different terms. Patent 10,383,834 should therefore be analyzed as one asset within the broader intravenous acetaminophen estate.

What is the FDA regulatory status of the covered product?

The principal branded product associated with intravenous acetaminophen is Ofirmev, marketed in the United States under FDA-approved labeling for intravenous use.[2]

The FDA label includes dosing for adults and adolescents weighing at least 50 kg. It describes a 650 mg dose every four hours or a 1,000 mg dose every six hours, with a maximum daily dose of 4,000 mg in appropriate patients.[2]

The patent claim uses a daily dose of less than 4,000 mg. A 650 mg every-four-hour schedule produces 3,900 mg per day and maps directly onto that limitation.

The label also specifies administration by intravenous infusion over approximately 15 minutes. That dosing instruction is relevant to dependent claims 3, 4, 10, and 11.[2]

What is the Orange Book status of US Patent 10,383,834?

A patent is relevant to the Orange Book only if it is submitted and listed in connection with an approved drug application. Patent 10,383,834 is a method-of-use patent, which makes its Orange Book treatment dependent on the use code submitted by the NDA holder and accepted by FDA.

The relevant regulatory questions are:

Whether patent 10,383,834 is listed against the Ofirmev NDA.
Whether FDA identifies a use code covering the 650 mg every-four-hour regimen.
Whether the listed use code is sufficiently specific to support a section viii “skinny label” carve-out.
Whether the patent remains listed after any expiration, delisting, or administrative update.

A listed method-of-use patent can trigger a Paragraph IV certification from an ANDA applicant. If the applicant seeks approval for an indication or dosing instruction covered by the patent, the NDA holder may bring an infringement action within 45 days, potentially creating a 30-month stay under the Hatch-Waxman framework.[3]

The patent number alone does not establish the current Orange Book listing status. The FDA Orange Book patent-and-exclusivity database is the controlling regulatory source for the listing question.[4]

What Paragraph IV challenges could target this patent?

An ANDA applicant could challenge the patent through a Paragraph IV certification asserting that the patent is invalid, unenforceable, or will not be infringed by the proposed generic product.[3]

Potential invalidity arguments include:

Obviousness

The central regimen combines known variables:

650 mg acetaminophen;
intravenous administration;
four-hour repeat dosing;
a sub-4,000 mg daily ceiling;
administration to patients weighing at least 50 kg.

An accused generic applicant could argue that the claimed regimen would have been obvious from earlier intravenous acetaminophen labeling, clinical studies, conventional acetaminophen dosing, and known hepatic-safety limits. The patent holder would likely rely on the specific combination, clinical tolerability, pharmacokinetic performance, or claimed reduction in dosing burden.

Written description and enablement

The claims cover both pain and fever, sterile solution and lyophilized powder, and a range of infusion times. A challenger could test whether the specification provides adequate support across that full scope.

This risk is more relevant to the dependent claims if the specification does not provide sufficient examples for every formulation presentation or administration interval.

Claim construction

The terms “about 650 mg,” “every four hours,” and “less than 4000 mg” may determine the outcome of a literal infringement dispute. The prosecution history could narrow or broaden the practical interpretation of those terms.

Double patenting

Because the patent appears within a continuation family, an ANDA challenger could examine terminal disclaimers, parent claims, and overlapping method claims for obviousness-type double-patenting issues.

Which companies are challenging intravenous acetaminophen exclusivity?

The competitive market consists primarily of the Ofirmev branded product and FDA-approved generic intravenous acetaminophen products. Generic manufacturers may enter through an ANDA rather than through a biosimilar application because acetaminophen is a small-molecule active ingredient, not a biologic.[5]

Likely competitive categories include:

Competitor type	Regulatory pathway	Principal risk
Generic IV acetaminophen manufacturer	ANDA	Paragraph IV litigation and label carve-out issues
Hospital injectable supplier	ANDA or authorized generic arrangement	Price competition and supply substitution
Branded product owner	NDA	Orange Book listing and enforcement
Contract manufacturer	Commercial supply agreement	Manufacturing and formulation know-how exposure

The exact litigation position depends on the current ANDA docket, Paragraph IV notices, Orange Book records, and any settlements. A generic product may be approved while omitting patented indications or dosing instructions, but actual hospital use can still create inducement risk if the manufacturer promotes the patented regimen.

What generic launch risks exist?

Full-label launch

A generic applicant that reproduces the 650 mg every-four-hour regimen for patients weighing at least 50 kg would present the highest infringement exposure. The label could map directly to claims 1 and 8 and to the 15-minute infusion claims.

Skinny-label launch

A generic applicant could seek approval for unpatented uses or dosing regimens while carving out the patented method under section viii of the Federal Food, Drug, and Cosmetic Act.[3]

This strategy reduces label-based inducement exposure but does not eliminate all risk. Hospitals may still administer the generic product according to the patented regimen. The manufacturer’s promotional materials, prescribing information, sales communications, and product design could become relevant to an induced-infringement claim.

1,000 mg every six hours

A label limited to 1,000 mg every six hours does not literally satisfy the approximately 650 mg limitation or the every-four-hour limitation. It also reaches the 4,000 mg daily maximum rather than the claimed sub-4,000 mg maximum.

That regimen is a stronger design-around position, although it could implicate separate patent claims or regulatory restrictions.

Lower-dose or lower-frequency regimens

A 500 mg dose, a six-hour interval, or a maximum daily dose of 3,000 mg may avoid literal infringement of the supplied claims. The commercial downside is that the alternative regimen may not match the branded label or hospital dosing preference.

How strong is the patent estate?

The claim set has moderate strength against an exact labeled copy of the patented regimen and weaker strength against a generic product designed around the dosing limitations.

Factor	Assessment
Literal read-on against 650 mg q4h label	High
Coverage of ordinary IV acetaminophen products	Limited
Formulation specificity	Low to moderate
Method-of-use enforceability	Fact-dependent
Skinny-label vulnerability	Significant
Obviousness exposure	Material
Manufacturing barrier	Low based on supplied claims
Biological-product substitution risk	Not applicable
Expiration runway	Through approximately 2030, subject to term adjustment

The patent does not create a meaningful manufacturing barrier by itself. It does not claim a specific synthesis route, purification process, container, or formulation composition. A competitor that can produce a therapeutically equivalent intravenous acetaminophen product may avoid the patent through label design or dosing changes.

What patent litigation and settlements matter?

The supplied claim text does not identify a litigation docket, Paragraph IV notice, settlement agreement, consent judgment, or license affecting Patent 10,383,834. Those matters must be evaluated separately from the intrinsic claim scope.

For transaction diligence, the relevant documents are:

ANDA Paragraph IV notices;
district-court complaints under 21 U.S.C. § 355(j)(5)(B)(iii);
claim-construction orders;
invalidity and noninfringement opinions;
settlement and license agreements;
Orange Book listing updates;
FDA approval letters and labeling carve-outs.

A license that covers the Ofirmev patent family may not cover every continuation patent, every formulation patent, or every country outside the United States.

How does this patent compare with formulation and manufacturing patents?

Patent 10,383,834 is narrower than a composition patent but broader than a claim limited to one commercial vial or one manufacturing process.

Patent type	Typical protected subject matter	Relationship to Patent 10,383,834
Method-of-use patent	Dose, frequency, patient, indication	This patent
Composition patent	Acetaminophen concentration, excipients, stability	Separate potential barrier
Formulation patent	Sterility, pH, container, solvent, stability	Not materially claimed here
Manufacturing patent	Synthesis, purification, filling, lyophilization	Not claimed here
Regulatory exclusivity	FDA statutory exclusivity	Separate from patent term
Trademark protection	Ofirmev branding	Does not block generic use of acetaminophen

The patent may be important in combination with other family members, but its supplied claims alone do not prevent a competitor from making every form of intravenous acetaminophen.

Key Takeaways

US Patent 10,383,834 claims a specific intravenous acetaminophen regimen, not acetaminophen generally.
The core limitations are approximately 650 mg, every four hours, a patient weight of at least 50 kg, and a daily dose below 4,000 mg.
Six 650 mg administrations total 3,900 mg and fit the claimed daily-dose limitation.
Claims cover pain and fever, with narrower claims for acute pain, postoperative pain, sterile solutions, 15-minute infusion, and reconstituted lyophilized powder.
A generic label reproducing 650 mg every four hours presents the clearest infringement risk.
A 1,000 mg every-six-hour label provides a stronger literal noninfringement position.
The patent is a small-molecule method-of-use patent, so biosimilar rules do not apply.
The base patent term appears to extend to approximately April 2030, subject to the USPTO’s final patent-term-adjustment calculation.
The patent does not independently create a formulation or manufacturing barrier.
Orange Book listing, Paragraph IV activity, litigation, licenses, and settlements require review of the current FDA and court records.

FAQs About US Patent 10,383,834

Does 650 mg every six hours infringe Patent 10,383,834?

It does not literally satisfy the every-four-hour limitation. Other patents, labeling theories, or a doctrine-of-equivalents argument could still affect the risk analysis.

Does a 1,000 mg intravenous acetaminophen dose infringe this patent?

A 1,000 mg dose does not literally meet the approximately 650 mg limitation. A regimen of 1,000 mg every six hours also differs from the claimed frequency and daily-dose limitation.

Can a generic manufacturer sell intravenous acetaminophen before the patent expires?

Potentially. The manufacturer could pursue a Paragraph IV challenge, a section viii label carve-out, a license, or a noninfringing dosing strategy. Approval and commercial launch depend on the full Orange Book and litigation record.

Does the patent cover oral acetaminophen?

No. The claims require intravenous administration.

Does the patent cover patients weighing less than 50 kg?

No. Claims 1 and 8 expressly require a human subject weighing at least 50 kg.

References

United States Patent and Trademark Office. (2019). U.S. Patent No. 10,383,834, Methods of treating pain and fever using intravenous acetaminophen.
U.S. Food and Drug Administration. (2023). Ofirmev (acetaminophen injection) prescribing information.
Federal Food, Drug, and Cosmetic Act, 21 U.S.C. § 355(j).
U.S. Food and Drug Administration. (2025). Approved drug products with therapeutic equivalence evaluations: Orange Book.
U.S. Food and Drug Administration. (2018). Generic drugs: Questions and answers.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Mallinckrodt Hosp	OFIRMEV	acetaminophen	SOLUTION;INTRAVENOUS	022450-001	Nov 2, 2010		DISCN	Yes	No	10,383,834*PED	⤷ Start Trial			Y		⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Canada	2705733	⤷ Start Trial
Japan	2011503198	⤷ Start Trial
Japan	5909750	⤷ Start Trial
World Intellectual Property Organization (WIPO)	2009064928	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Summary for Patent: 10,383,834