CLINICAL TRIALS PROFILE FOR TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN

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505(b)(2) Clinical Trials for TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN

This table shows clinical trials for potential 505(b)(2) applications. See the next table for all clinical trials

Trial Type	Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
OTC	NCT01588158 ↗	Patient Satisfaction With Pain Relief After Ambulatory Hand Surgery	Terminated	Massachusetts General Hospital	Phase 4	2012-07-01	Adequate pain relief has been a priority of the Joint Commission and is featured on national inpatient surveys such as the H-CAHPS. When considering methods for improving satisfaction with pain relief in the United States, a great deal of emphasis has been placed on opioid pain medications. Some of this emphasis on opioid pain medication is driven by the pharmaceutical industry and by advocacy groups with ties to the pharmaceutical industry. There is evidence that the "pain is the fifth vital sign" campaign of the Joint Commission led to an increased incidence of prescription of opioids, but there is less evidence of improved satisfaction with pain relief. There is some evidence of an increase in opioid-related adverse events. As the sales of opioids have tripled from 1999-2008, so has the number of deaths caused by opioid overdose; 14,800 in 2008. The number of visits to the Emergency Department for opioid overdose doubled between 2004 and 2008. Patients in other countries take far less opioid pain medication and are equally satisfied with pain relief. For instance, Lindenhovius et al. found in a retrospective study that Dutch patients take a weak (Tramadol) or no opioid pain medication after ankle fracture surgery and have comparable or better satisfaction with pain relief than American patients, most of whom take oxycodone. That study was repeated prospectively (unpublished) and confirmed that Dutch patients do not feel their pain is undertreated. A study of morphine use after a femur fracture demonstrated that American patients used far more than Vietnamese patients (30 mg/kg versus 0.9 mg/kg), but were more dissatisfied with their pain relief. These sociological differences are striking and suggest strongly that personal factors may be the most important determinant of satisfaction with pain relief. It is our impression that most American hand surgeons give patients a prescription for an opioid pain medication after carpal tunnel release, and that is certainly true in our practice. This seems to be based primarily on the outliers, and intended to avoid confrontation with patients that desire opioids; however, most patients take little or no narcotic pain medication, and many who do use the opioids complain of the side effects-nausea and pruritis in particular. It is therefore not clear whether routine opioids is the optimal pain management strategy after carpal tunnel release. In the study of Stahl et al. from Israel, patients were prescribed acetaminophen rather than opioids after carpal tunnel release and only 20 of 50 patients used acetaminophen; 30 patients did not use acetaminophen or other pain medication at all after the operation. Our aim is to determine if there is a difference in satisfaction with pain relief between patients advised to take opioids compared to patients advised to use over the counter acetaminophen after carpal tunnel release under local anesthesia. A secondary aim is to determine if personal factors account for more of the variability in satisfaction with pain relief than opioid strategy.

All Clinical Trials for TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00210561 ↗	A Study of the Effectiveness and Safety of Tramadol HCl/Acetaminophen Compared to Placebo in Treating Acute Low Back Pain	Terminated	PriCara, Unit of Ortho-McNeil, Inc.	Phase 4	2005-03-01	The purpose of this study is to explore the pain-relieving effects and safety of Tramadol HCl/acetaminophen as compared to placebo in patients experiencing acute low back pain. Tramadol HCl/acetaminophen is approved for short-term management of acute pain. The combination of tramadol HCl/acetaminophen has been shown to be effective for the treatment of acute musculoskeletal pain. Patients who experienced at least moderate acute low back pain for 2 to 10 days before study entry will be randomized to receive either tramadol HCl/acetaminophen or placebo.
NCT00210561 ↗	A Study of the Effectiveness and Safety of Tramadol HCl/Acetaminophen Compared to Placebo in Treating Acute Low Back Pain	Terminated	Johnson & Johnson Pharmaceutical Research & Development, L.L.C.	Phase 4	2005-03-01	The purpose of this study is to explore the pain-relieving effects and safety of Tramadol HCl/acetaminophen as compared to placebo in patients experiencing acute low back pain. Tramadol HCl/acetaminophen is approved for short-term management of acute pain. The combination of tramadol HCl/acetaminophen has been shown to be effective for the treatment of acute musculoskeletal pain. Patients who experienced at least moderate acute low back pain for 2 to 10 days before study entry will be randomized to receive either tramadol HCl/acetaminophen or placebo.
NCT00210847 ↗	A Study Comparing the Effectiveness and Safety of Tramadol HCl/Acetaminophen Versus Placebo for the Treatment of Painful Neuropathy in Diabetic Patients	Completed	PriCara, Unit of Ortho-McNeil, Inc.	Phase 3	2003-12-01	The purpose of this study is to explore the pain-reieiving effects and safety of tramadol HCl/acetaminophen as compared to placebo in patients experiencing painful diabetic neuropathy. Treatment of neuropathic pain often requires the use of more than one medication. The pain-relieving potential of tramadol HCl/acetaminophen for the treatment of painful diabetic neuropathy comes from the multiple mechanisms of action in this combination pain medication. Patients who experience painful diabetic neuropathy will be enrolled in this study.
NCT00210847 ↗	A Study Comparing the Effectiveness and Safety of Tramadol HCl/Acetaminophen Versus Placebo for the Treatment of Painful Neuropathy in Diabetic Patients	Completed	Johnson & Johnson Pharmaceutical Research & Development, L.L.C.	Phase 3	2003-12-01	The purpose of this study is to explore the pain-reieiving effects and safety of tramadol HCl/acetaminophen as compared to placebo in patients experiencing painful diabetic neuropathy. Treatment of neuropathic pain often requires the use of more than one medication. The pain-relieving potential of tramadol HCl/acetaminophen for the treatment of painful diabetic neuropathy comes from the multiple mechanisms of action in this combination pain medication. Patients who experience painful diabetic neuropathy will be enrolled in this study.

Clinical Trial Conditions for TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN

Condition Name

Condition Name for TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN
Intervention	Trials
Pain	10
Pain, Postoperative	8
Postoperative Pain	5
Chronic Pain	5

Condition MeSH

Condition MeSH for TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN
Intervention	Trials
Pain, Postoperative	18
Osteoarthritis	8
Chronic Pain	8
Low Back Pain	7

Clinical Trial Locations for TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN

Trials by Country

Trials by Country for TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN
Location	Trials
United States	34
Canada	7
Korea, Republic of	5
Turkey	5
Italy	5

Trials by US State

Trials by US State for TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN
Location	Trials
Texas	7
Florida	3
New York	2
Michigan	2
Maryland	2

Clinical Trial Progress for TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN

Clinical Trial Phase

Clinical Trial Phase for TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN
Clinical Trial Phase	Trials
PHASE4	2
PHASE2	2
PHASE1	1

Clinical Trial Status

Clinical Trial Status for TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN
Clinical Trial Phase	Trials
Completed	52
Recruiting	11
Not yet recruiting	10

Clinical Trial Sponsors for TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN

Sponsor Name

Sponsor Name for TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN
Sponsor	Trials
Janssen Korea, Ltd., Korea	10
PriCara, Unit of Ortho-McNeil, Inc.	5
Johnson & Johnson Pharmaceutical Research & Development, L.L.C.	5

Sponsor Type

Sponsor Type for TRAMADOL HYDROCHLORIDE AND ACETAMINOPHEN
Sponsor	Trials
Other	75
Industry	39
U.S. Fed	6

Tramadol Hydrochloride and Acetaminophen (Combination) Clinical Trials Update, Market Analysis, and Generic/Biosimilar Forecasts

Last updated: July 27, 2026

Tramadol hydrochloride and acetaminophen is a fixed-dose opioid analgesic combination with an FDA approval history centered on immediate-release tablets. The near-to-mid term market outlook is driven by: (1) ongoing opioid-safety and controlled-substance enforcement, (2) payer and formulary restrictions, (3) state and federal litigation risk that reshapes manufacturer demand, and (4) patent and regulatory status that affects generic entry timing and pricing pressure. Clinical-trial activity remains mostly incremental because the core product is already established; most new “trials” are tightening safety, abuse-deterrence, or special populations rather than changing the active ingredient.

Clinical trials update for tramadol hydrochloride and acetaminophen: What studies are ongoing and what endpoints matter?

Are there active interventional trials (new endpoints) for the fixed-dose combination?

For the fixed-dose tramadol/acetaminophen tablet, most recent trial activity is typically concentrated in:

• Pain intensity change (baseline-to-study end)
• Responder rates (e.g., proportion achieving clinically meaningful pain reduction)
• Time to meaningful pain relief
• Safety endpoints focused on respiratory depression risk, falls, misuse/abuse indicators, and hepatic safety with acetaminophen exposure limits
• Special population substudies (elderly, hepatic impairment, renal impairment, concomitant CNS depressants)

What endpoint types dominate recent trial designs?

Clinical studies for established opioid combinations generally use:

• Time-based analgesic efficacy windows (first dose and maintenance)
• Patient-reported outcomes (pain scores) plus rescue medication consumption
• Safety monitoring for sedation, dizziness, nausea, constipation
• Hepatic injury surveillance aligned to acetaminophen exposure
• Abuse-deterrence and misuse behavior measures when included by protocol or regulator/payer request

What new delivery systems are competing in trials?

Where the combination is the focus of new trials, investigators tend to evaluate:

• Alternative release profiles (still usually oral, less often topical for this molecule)
• Dose-optimization strategies to reduce acetaminophen exposure
• Risk-mitigation workflows such as education and monitoring rather than novel pharmacology

Market implication: incremental trials rarely change the regulatory status of the original immediate-release combination, but they can strengthen label language that payers use to manage utilization and can affect post-marketing safety controls.

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What patents protect tramadol hydrochloride and acetaminophen combinations, and when do they expire?

How patent coverage works for fixed-dose tramadol/acetaminophen tablets

For established branded fixed-dose opioid combinations, patent estates typically cluster around:

• Composition-of-matter (less common for already-known actives)
• Pharmaceutical compositions (specific salt/ratios)
• Manufacturing/process parameters (tablet formation)
• Method-of-use (dosing regimens for specific pain indications)
• Formulation improvements (excipients, stability, dissolution)

What matters for exclusivity timing and generic entry?

For market access planning, the controlling factors are:

• Patent expiration on formulation/manufacturing or method-of-use that blocks generic substitution
• Whether any secondary patents are “carved out” in an FDA ANDA certification context
• FDA exclusivity categories (or lack of them) for the branded product, typically less central for older combinations than patent dates

Practical takeaway: generics face risk primarily from Orange Book-listed patents rather than from pharmacology novelty. If the branded estate is thin beyond foundational approvals, generic entry becomes earlier and price compression accelerates.

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What is the Orange Book status of tramadol hydrochloride and acetaminophen (ANDAs, Paragraph IV, listed patents)?

Orange Book mechanics investors should track

The key Orange Book fields for this class are:

• Listed drug products (strengths and dosage forms)
• Patent numbers and expiration dates
• Patent type (composition, method of use, formulation, process)
• Certification type for each ANDA filing:
  • Paragraph III (patent expires on a date)
  • Paragraph IV (patent challenge)
  • Carve-out risks if not all patents are challenged

Why Paragraph IV matters

For opioid combinations, Paragraph IV challenges are often less about safety and more about whether the sponsor can clear listed patent hurdles to secure FDA approval and market entry without infringing.

Commercial implication: the timing of Paragraph IV litigation outcomes strongly affects:

• First generic launch date
• How many ANDAs launch in parallel
• Wholesaler and PBM pricing dynamics in months following approval

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How many generics are likely for tramadol hydrochloride and acetaminophen, and what entry risks exist?

Typical generic competitive scenario for established opioid combinations

Assuming Orange Book barriers are manageable, a common pattern is:

• Multiple ANDA approvals within a narrow time band after the first bottleneck patent expires or is cleared
• Fast shelf-price declines due to commoditization
• Channel-specific availability differences (hospital vs retail, contract distribution)

Generic entry risks specific to opioid fixed-dose combinations

• Remaining unexpired patents that are not successfully challenged
• Litigation-triggered delays (temporary restraining orders, settlement-based “at-risk” outcomes)
• Label constraints tied to REMS-like safety controls (even when not formally under REMS, opioid utilization remains managed via distribution rules)
• Supply chain dependence on particular manufacturing sites for tablet strengths

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What patent litigation affects tramadol hydrochloride and acetaminophen, and what settlement patterns drive delays?

What to look for in opioid combination litigation

Common litigation drivers in fixed-dose opioid combinations:

• Disputed infringement around dissolution, formulation parameters, or method-of-use dosing
• Procedural timelines for preliminary injunctions
• Settlement agreements that govern “launch at” or “launch before” generic dates

How settlements typically impact market share

Market outcomes usually reflect:

• Delayed launch for the first filer(s) that settled or lost
• Carve-outs that let some generics launch earlier at specific strengths
• A staged entry pattern: partial strength coverage first, then full portfolio

Decision lens: licensing and investment timing should map expected launch calendars to strength-by-strength Orange Book clearing.

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How does tramadol hydrochloride and acetaminophen compare with single-entity tramadol or other opioid combinations on efficacy and risk?

Efficacy comparison

The rationale for combining tramadol with acetaminophen is additive analgesia through different mechanisms. Clinically, that often translates into:

• Similar or better pain reduction versus monotherapy in moderate acute pain populations
• Lower dose exposure per component versus higher-dose monotherapy strategies

Risk comparison

Risk profiles differ by component:

• Opioid exposure drives respiratory depression risk and CNS adverse events
• Acetaminophen exposure drives hepatic injury risk if total daily dose limits are exceeded

Competitive substitution pressure

Payers and prescribers often steer based on:

• Safety policy changes and prior authorization
• Contraindication screening (liver disease, alcohol use disorder, concomitant sedatives)
• Cost and formulary positioning versus alternatives (e.g., other immediate-release combinations)

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Market analysis: How big is the tramadol hydrochloride and acetaminophen opportunity, and what drives revenue over the next 5 years?

Demand drivers

1. Persistent demand for oral immediate-release analgesics in acute and chronic pain settings where fixed-dose combinations remain acceptable.
2. PBM and formulary structures that allow coverage with restrictions (quantity limits, step therapy, prescriber requirements).
3. Substitution dynamics: when branded pricing rises, generics and alternative combinations capture share.

Headwinds

1. Opioid risk management pressure from regulators and litigators reduces utilization growth.
2. Payer policies increasingly constrain opioid combinations versus non-opioid or abuse-deterrent options.
3. Liver safety awareness and acetaminophen limit education affect prescribing.

Market structure

• High generic participation once Orange Book barriers lift
• Retail and mail order volume as primary distribution channels
• Hospital use for post-acute pain often depends on local formularies

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5-year market projection for tramadol hydrochloride and acetaminophen: Base case, upside, and downside

Base case (most likely)

• Continued utilization under formulary restrictions.
• Gradual share shifts toward the lowest-cost generics.
• Revenue growth, if any, is typically value-neutral, driven by price-mix rather than volume expansion.

Upside case

• Faster-than-expected generic clearances for additional strengths increase supply stability and reduce shortages.
• Label refinement or safety messaging improves physician confidence, stabilizing volume.

Downside case

• Additional controlled-substance enforcement and payer tightening reduces eligible prescriber populations.
• Litigation and distribution reforms reduce commercial momentum for manufacturers and distributors.

Model logic used for projections (high level):

• Start with population-level opioid utilization trends and adjust for formulary restrictions.
• Apply expected generic price erosion after first meaningful launch wave.
• Assume demand elasticity to price is moderate because opioids face both clinical and policy constraints.

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Which companies are positioned to lead the tramadol/acetaminophen generic market after patent expiry?

How to identify market leaders

In this category, leadership typically comes from:

• ANDA portfolios with coverage across multiple strengths
• Manufacturing reliability for tablets (compressibility, dissolution specs)
• Contracting with wholesalers and PBMs to win bid cycles

Commercial advantage

The strongest generic players typically:

• Launch multiple SKUs quickly to maximize shelf share.
• Use aggressive rebate strategies if allowed under PBM rules.
• Maintain steady supply to avoid delisting or substitution by pharmacists.

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How strong is the patent estate for tramadol/acetaminophen, and what does that mean for licensing strategy?

Patent strength indicators for this drug class

• Number of Orange Book-listed patents remaining and their expiration spread
• Whether patents cover broad composition vs narrow formulation/process details
• Likely litigation outcomes based on prior challenge patterns in similar opioid combinations

Licensing implications

• If the remaining estate is mostly narrow formulation/process patents, licensing value is higher for specific manufacturing know-how rather than broad market exclusivity.
• If method-of-use patents are asserted and harder to “design around,” licensing becomes a barrier to generic entry at scale.

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What generic launch scenarios exist for tramadol hydrochloride and acetaminophen (strength-by-strength)?

Scenario 1: Full portfolio clearance

• Multiple strengths approve within a short window after key patent expiration or successful challenge.
• Rapid price compression across the product line.

Scenario 2: Strength carve-outs

• Only selected strengths launch first due to patent coverage or carve-outs.
• Remaining strengths launch later, creating interim price stability for those strengths.

Scenario 3: Litigation delay

• Court or settlement delays push launches out by 6 to 36 months relative to the base expiry date.
• Launches occur in smaller waves.

Execution focus: map predicted approval waves to strength SKU count because procurement and payer contracts track strength-specific NDCs.

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FDA and regulatory outlook: What pathway and labeling trends matter for tramadol/acetaminophen?

ANDA pathway dynamics

• Generic approvals depend on ANDA chemistry/manufacturing controls and bioequivalence.
• Labeling is typically aligned to reference product unless changes are negotiated or required by regulatory events.

Safety-driven label tightening

• Opioid class warnings and acetaminophen hepatic risk counseling remain recurring label themes.
• Any safety communications can drive prescriber behavior and reduce net volume even without formal regulatory restriction.

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Key Takeaways

• Clinical trial activity for tramadol hydrochloride and acetaminophen is largely incremental and safety- and endpoint-focused rather than changing the core regulatory product.
• Market outlook depends more on formulary restrictions, opioid policy enforcement, and patent/Orange Book clearing than on breakthrough efficacy.
• Generic entry risk is driven by Orange Book-listed patents and Paragraph IV litigation outcomes, which can create strength-by-strength launch waves.
• The most likely commercial path is continued utilization with increasing generic pricing pressure and value shift to the lowest-cost suppliers.
• Licensing and investment should prioritize remaining Orange Book patent coverage and expected litigation settlement calendars by strength and dosage form.

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FAQs

1. When do tramadol hydrochloride and acetaminophen lose exclusivity in the US?
2. Do Paragraph IV challenges exist for tramadol/acetaminophen generics, and how do they affect launch dates?
3. What Orange Book patents typically block generic tramadol/acetaminophen tablets (composition vs method-of-use)?
4. How do payer prior authorization and quantity limits change tramadol/acetaminophen demand?
5. Which strengths (e.g., dose ratios) are most exposed to faster generic substitution?

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References

1. FDA Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations. (U.S. Food and Drug Administration).
2. FDA Drug Trials Snapshots. (U.S. Food and Drug Administration).
3. FDA Drug Safety Communications on opioids and acetaminophen hepatic risk. (U.S. Food and Drug Administration).