CLINICAL TRIALS PROFILE FOR ACETAMINOPHEN, ASPIRIN AND CAFFEINE

505(b)(2) Clinical Trials for ACETAMINOPHEN, ASPIRIN AND CAFFEINE

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	NCT04132336 ↗	Study to Find Out the Optimal Dose of Caffeine in the Combination Tablet of Naproxen Sodium and Caffeine in Patients Experiencing Moderate to Severe Pain After Having Wisdom Teeth Removed	Completed	Bayer	Phase 2	2019-11-12	The researchers in this study wanted to find out the optimal dose of Caffeine in the combination tablet of Naproxen Sodium and Caffeine that works in patients experiencing moderate to severe pain after having wisdom teeth removed. In the US, Naproxen has been marketed since 1976, and Naproxen Sodium has been approved for over-the-counter (OTC) use since 1994 for the temporary relief of minor aches and pains. Caffeine, which is generally consumed as coffee, tea or cocoa, has been shown to enhance the effectiveness of various pain relievers, and therefore is accepted as an additive to painkillers like aspirin and acetaminophen. Patients participating in this study underwent a surgery to remove 3 or 4 wisdom teeth. If the pain severity after the surgery met the study requirement, patients would receive oral tablet(s) of Naproxen Sodium and Caffeine, or Naproxen Sodium, or Caffeine, or placebo (drug with no active ingredient). Patients could also receive additional pain medication when needed. Researchers would also learn if the patients have any medical problems during the study.

All Clinical Trials for ACETAMINOPHEN, ASPIRIN AND CAFFEINE

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00471952 ↗	Maxalt 10mg Plus Caffeine 75mg in the Acute Treatment of Migraine Headache	Completed	Merck Sharp & Dohme Corp.	Phase 3	2007-04-01	The purpose of this study is to evaluate the effect of rizatriptan, alone or combined with caffeine for treating acute attacks of migraine. Each subject will have 3 months to treat 3 acute migraine headache attacks. Each subject will be dispensed one box containing 3 packets of study medication labeled for Headache #1, Headache #2, or Headache #3. Each packet wil contain either Maxalt 10mg MLT or a Maxalt placebo (sugar pill), and a capsule containing either caffeine 75mg or a capsule containing placebo (sugar). One headache will be treated with a combination of Maxalt 10mg MLT and caffeine. Another headache will be treated with a combination of Maxalt 10mg MLT and a capsule containing placebo. A third headache will be treated with just placebo. Neither the subject, the study coordinator, or your study doctor will know in which order you will receive the three different treatments. This information is available in case of emergency.
NCT00471952 ↗	Maxalt 10mg Plus Caffeine 75mg in the Acute Treatment of Migraine Headache	Completed	Diamond Headache Clinic	Phase 3	2007-04-01	The purpose of this study is to evaluate the effect of rizatriptan, alone or combined with caffeine for treating acute attacks of migraine. Each subject will have 3 months to treat 3 acute migraine headache attacks. Each subject will be dispensed one box containing 3 packets of study medication labeled for Headache #1, Headache #2, or Headache #3. Each packet wil contain either Maxalt 10mg MLT or a Maxalt placebo (sugar pill), and a capsule containing either caffeine 75mg or a capsule containing placebo (sugar). One headache will be treated with a combination of Maxalt 10mg MLT and caffeine. Another headache will be treated with a combination of Maxalt 10mg MLT and a capsule containing placebo. A third headache will be treated with just placebo. Neither the subject, the study coordinator, or your study doctor will know in which order you will receive the three different treatments. This information is available in case of emergency.
NCT01080677 ↗	Caffeine/Propranolol Intervention for Acute Migraine	Completed	Stanford University	Phase 2	2007-01-01	This is a research study to assess the safety of caffeine/propranolol at different dose levels. We want to find out what effects, good and/or bad, it has on patients and their migraines.
NCT01248468 ↗	Efficacy and Safety of Acetaminophen, Aspirin and Caffeine With Sumatriptan in the Acute Treatment of Migraine	Completed	Novartis	Phase 4	2010-11-01	The main purpose of this study is to compare the efficacy and safety of aspirin, acetaminophen and caffeine (AAC) with sumatriptan and placebo in the acute treatment of migraine.
NCT01629329 ↗	Prochlorperazine Versus Acetaminophen, Aspirin, and Caffeine for the Treatment of Acute Migraine	Terminated	Albert Einstein Healthcare Network	Phase 4	2010-11-01	The objective of this randomized, double blind study is to demonstrate that one dose oral "excedrin migraine" (acetaminophen, aspirin and caffeine) is not inferior when compared to one dose of intravenous prochlorperazine for the treatment of acute migraine headaches in the emergency department.
NCT02021474 ↗	A Multicenter, Randomized, Double-blind, Placebo-controlled Trial to Assess the Efficacy and Safety of Subcutaneous Histamine Dihydrochloride for Migraine Prophylaxis	Unknown status	AgoneX Biopharmaceuticals, Inc.	Phase 2	2015-09-01	This is a prospective multi-center, randomized, double-blind, two treatment period, placebo-controlled study in subjects with migraine headache requiring prophylactic treatment. The patients will be randomized to receive either histamine dihydrochloride sc or placebo (matching vehicle only) sc for 16 weeks. The safety and efficacy outcome measures will be assessed at selected dosing segments during the 16 week treatment phase and 4 weeks (week 20), 8 weeks (week 24) after the last Injection.
NCT02021474 ↗	A Multicenter, Randomized, Double-blind, Placebo-controlled Trial to Assess the Efficacy and Safety of Subcutaneous Histamine Dihydrochloride for Migraine Prophylaxis	Unknown status	BioHealthonomics Inc.	Phase 2	2015-09-01	This is a prospective multi-center, randomized, double-blind, two treatment period, placebo-controlled study in subjects with migraine headache requiring prophylactic treatment. The patients will be randomized to receive either histamine dihydrochloride sc or placebo (matching vehicle only) sc for 16 weeks. The safety and efficacy outcome measures will be assessed at selected dosing segments during the 16 week treatment phase and 4 weeks (week 20), 8 weeks (week 24) after the last Injection.

Clinical Trial Conditions for ACETAMINOPHEN, ASPIRIN AND CAFFEINE

Condition Name

Condition Name for ACETAMINOPHEN, ASPIRIN AND CAFFEINE
Intervention	Trials
Pain, Postoperative	1
Postural Low Back Pain	1
Mechanical Low Back Pain	1
Migraine Disorders	1

Condition MeSH

Condition MeSH for ACETAMINOPHEN, ASPIRIN AND CAFFEINE
Intervention	Trials
Migraine Disorders	5
Headache	2
Low Back Pain	1
Back Pain	1

Clinical Trial Locations for ACETAMINOPHEN, ASPIRIN AND CAFFEINE

Trials by Country

Trials by Country for ACETAMINOPHEN, ASPIRIN AND CAFFEINE
Location	Trials
United States	17

Trials by US State

Trials by US State for ACETAMINOPHEN, ASPIRIN AND CAFFEINE
Location	Trials
Utah	2
California	2
Illinois	2
Pennsylvania	1
Washington	1

Clinical Trial Progress for ACETAMINOPHEN, ASPIRIN AND CAFFEINE

Clinical Trial Phase

Clinical Trial Phase for ACETAMINOPHEN, ASPIRIN AND CAFFEINE
Clinical Trial Phase	Trials
Phase 4	2
Phase 3	2
Phase 2	3

Clinical Trial Status

Clinical Trial Status for ACETAMINOPHEN, ASPIRIN AND CAFFEINE
Clinical Trial Phase	Trials
Completed	4
Unknown status	1
Not yet recruiting	1

Clinical Trial Sponsors for ACETAMINOPHEN, ASPIRIN AND CAFFEINE

Sponsor Name

Sponsor Name for ACETAMINOPHEN, ASPIRIN AND CAFFEINE
Sponsor	Trials
Stanford University	1
Novartis	1
Albert Einstein Healthcare Network	1

Sponsor Type

Sponsor Type for ACETAMINOPHEN, ASPIRIN AND CAFFEINE
Sponsor	Trials
Industry	6
Other	3

Acetaminophen, Aspirin and Caffeine (AAC) Clinical Trials Update, Market Analysis and Projection

Last updated: April 25, 2026

What is the current clinical and regulatory status of acetaminophen, aspirin and caffeine (AAC)?

AAC is a fixed-dose combination that has long-standing market authorization in multiple countries as an analgesic and antipyretic product. Clinical use centers on acute pain relief and headache, including migraine-associated symptoms, with dosing schedules aligned to established labeling rather than new molecular entities.

Trial activity (publicly visible landscape, last several years):

• New “first-in-class” AAC development is limited because the active ingredients and combinations are mature and off-patent in most jurisdictions.
• Observed clinical activity tends to fall into these buckets:
  • Formulation and bioavailability work (new tablets, dose rebalancing, stability or dissolution improvements).
  • Comparative efficacy/safety against single agents or other headache analgesics.
  • Real-world safety and tolerability evaluations through registries or post-marketing studies.
  • Special populations (e.g., older adults, adolescents) with protocol-driven safety endpoints.

Common endpoints in AAC studies:

• Pain intensity reduction over fixed time windows (often 30 to 120 minutes).
• Proportion achieving meaningful pain relief (responder analyses).
• Time to meaningful pain relief.
• Adverse event rates, with emphasis on GI events, bleeding risk indicators, and renal/hepatic safety markers.
• Caffeine tolerability (nervous system adverse events, sleep disruption signals in some protocols).

Which clinical trial categories dominate AAC updates?

Across AAC’s evidence base, the dominant investigational categories are:

1. Bioequivalence and formulation bridging

   • Designed to support manufacturing changes, new strengths, or updated dosage forms.
   • Typical readouts: Cmax, Tmax, AUC, and dissolution profiles under guideline-driven designs.

2. Headache and acute pain comparative trials

   • AAC is commonly compared with:
     • single-agent paracetamol/acetaminophen
     • aspirin monotherapy
     • other fixed-dose analgesic combinations (including those with different co-analgesics)
   • Typical design: randomized, double-blind, active-comparator, short-duration efficacy windows.

3. Safety-focused studies

   • Emphasis on:
     • GI tolerability and upper GI bleeding signals
     • aspirin-related risk mitigation and contraindication adherence
     • caffeine-related tolerability
   • Often post-authorization or registry-linked rather than pivotal pre-authorization programs.

Business implication: if a sponsor is planning incremental development, the most financeable clinical programs are formulation and controlled efficacy/safety bridges, not new mechanism-of-action clinical development.

What does the AAC market look like by channel, geography, and product role?

AAC sits in the OTC and pharmacy-dispensed analgesic segment in many markets, commonly sold for headache and general pain relief. Market structure is shaped by:

• OTC availability and low switching costs for consumers
• Brand concentration in some countries and generics in others
• Pricing pressure driven by mature competition
• Regulatory label constraints around aspirin exposure (GI bleeding risk), pediatric use restrictions, and caffeine-sensitive warnings

Market role by consumer need

AAC products are typically positioned as:

• Fast headache relief
• General pain relief (headache, minor aches and pains)
• Acute self-medication where OTC combination value matters

Competitive landscape (commercial reality for AAC)

The competitive set includes:

• branded multi-ingredient analgesics with different combinations
• single-ingredient acetaminophen or aspirin
• other “headache cocktail” combinations (varies by country)

Differentiation drivers that survive in mature segments:

• speed of onset and tolerability in label-supported claims
• price per dose and pack architecture
• pharmacist/consumer perception of efficacy

How large is the AAC market and what is the growth outlook?

A hard-dollar market size for “AAC as a distinct drug combination” is inconsistently reported across mainstream datasets because many sources aggregate fixed-dose analgesics or group combination analgesics at higher levels than ingredient-level pairings. The most actionable approach for projections in this category is to project volume through OTC analgesic consumption trends and adjust for:

• unit share shifts among combination vs single-agent analgesics
• generic penetration and brand dilution
• regulatory pressure on aspirin-containing products and caffeine-containing combinations
• substitution driven by price and availability

Directionally, the AAC segment tends to follow OTC analgesic demand with modest volume growth and pricing decline, with periodic uplift from product relaunches and seasonal peaks (headache seasons and cold/flu seasons).

Projection logic for AAC (volume-led, price-down baseline)

• Volume trend: steady demand for OTC analgesics; mild tailwinds from persistent headache prevalence.
• Price trend: structurally down over time due to generics and OTC competition.
• Net revenue: typically flat-to-low growth unless a sponsor captures share with a branded relaunch or differentiation platform.

What variables change AAC revenue outcomes in the next 3 to 5 years?

Key drivers that move results:

1. OTC category substitution

   • Combination analgesics vs single-agent analgesics
   • Consumer response to tolerability perceptions and guideline messaging

2. Aspirin-related label pressure

   • Updates or enforcement of contraindications
   • Risk communication on GI bleeding and pediatric/adolescent use restrictions (notably where aspirin labeling tightens)

3. Caffeine sensitivity and adverse event scrutiny

   • Market messaging and complaint rates affect repeat purchase
   • Some markets see consumer preference drift when caffeine warnings are prominent

4. Supply and manufacturing economics

   • Ingredient procurement, formulation cost, and logistics for unit-dose packaging
   • Contract manufacturing scale affects gross margin stability

5. Seasonality

   • Headache and pain cycles
   • Respiratory season for general aches and fever-related self-medication

Clinical development feasibility: what kinds of AAC programs can move the needle commercially?

Because the ingredients are mature, development that can produce commercial upside is typically limited to:

• OTC relaunch strategies
  • New pack sizes, dosing regimen optimization, or differentiation by dissolution profile
• Regulatory expansions
  • New strengths or route-of-administration formats where allowed
• Head-to-head evidence
  • Trials designed to support stronger, label-safe positioning in headache or acute pain
• Safety improvements
  • Studies that support reduced-risk claims, where regulators accept endpoints and real-world evidence

Most impactful programs are not “novel clinical efficacy,” but programs that reduce payer and regulatory friction for label expansion and improve consumer perceived benefit.

What is the realistic innovation pipeline for AAC?

In AAC, the innovation pipeline is usually:

• formulation and compliance upgrades
• stability improvements
• bioavailability bridging
• incremental trial data supporting labeling and promotional claim safety

A new mechanism-of-action AAC is not the commercial norm in markets where these ingredients already exist at scale.

How should investors and sponsors underwrite AAC market participation?

A defensible underwriting model uses:

• OTC analgesic growth forecasts at the country level
• category mix shifts (combination vs single)
• expected share capture from branding and distribution
• pricing and margin assumptions driven by genericization pace

Underwriting template (directional)

Revenue = (Total OTC analgesic demand) x (AAC combination share) x (AAC branded share) x (net price).

Key assumptions:

• combination share stable to modestly down in some markets
• AAC branded share depends on patent-like exclusivity substitutes (brand, formulation differentiation)
• net price declines unless sponsor maintains differentiation or exits low-margin channels

What are the top risks to AAC projections?

1. Regulatory tightening around aspirin-containing products
   • pediatric and adolescent restrictions, GI risk communications
2. Consumer drift to other analgesics
   • preferential use of acetaminophen-only products or other combination analgesics
3. Competitive intensity
   • generic entrants, price-based retail promotions
4. Safety-related recalls or adverse event spikes
   • concentrated adverse-event periods can change category consumption

Key Takeaways

• AAC development is largely mature and driven by formulation, bioequivalence, and short comparative efficacy work, not new molecular breakthroughs.
• The AAC market functions as a volume-led OTC analgesic segment with pricing pressure from generics and fixed-dose competition.
• Near-term growth is most likely modest and contingent on share capture via branding and packaging, plus label-consistent safety positioning.
• Commercial success depends on navigating aspirin label risk and caffeine tolerability perceptions, while maintaining competitive net pricing.

FAQs

1) Are there ongoing pivotal trials that could materially change AAC labeling?

AAC’s clinical activity is typically concentrated in formulation and bridging or short-duration comparative studies rather than new pivotal efficacy programs that would materially reset labeling.

2) What endpoints do AAC studies prioritize for pain claims?

Trials commonly prioritize pain intensity reduction over fixed time windows, responder proportions, time to meaningful pain relief, and adverse event profiling with GI and caffeine-related attention.

3) Why does AAC face less “new innovation” than newer drug classes?

The combination’s ingredients are mature, widely available, and largely off-patent in many markets, shifting development toward incremental formulation and regulatory bridging.

4) What most affects AAC revenue projections?

Category mix (combination vs single), branded vs generic share, net price, regulatory messaging around aspirin, and seasonal consumption patterns.

5) What development strategy is most realistic for an AAC entrant?

The most financeable strategy is typically formulation differentiation with bioequivalence support, plus label-relevant comparative or safety evidence designed to reduce regulatory and commercial friction.

References

[1] FDA. “Analgesic, Antipyretic, and Anti-Inflammatory Drug Products for Over-the-Counter Use.” U.S. Food and Drug Administration.
[2] EMA. “Guideline on the Investigation of Bioequivalence.” European Medicines Agency.
[3] World Health Organization. “WHO Model Formulary: Analgesics.” World Health Organization.