CLINICAL TRIALS PROFILE FOR ZYRTEC-D 12 HOUR

505(b)(2) Clinical Trials for ZYRTEC-D 12 HOUR

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	NCT02024152 ↗	Safety, Tolerability and Pharmacokinetics Trial of JDP-205 Injection 10 mg	Completed	Algorithme Pharma Inc	Phase 1	2011-03-01	This study is to investigate the pharmacokinetics (PK) together with the safety and tolerability of JDP-205 at 5 mg and 10 mg intravenous doses and 10 mg intramuscular dose, in comparison to the marketed cetirizine oral product Zyrtec® 10 mg tablets (an OTC product) in healthy male and female volunteers after a single dose administration.
OTC	NCT02024152 ↗	Safety, Tolerability and Pharmacokinetics Trial of JDP-205 Injection 10 mg	Completed	JDP Therapeutics, Inc.	Phase 1	2011-03-01	This study is to investigate the pharmacokinetics (PK) together with the safety and tolerability of JDP-205 at 5 mg and 10 mg intravenous doses and 10 mg intramuscular dose, in comparison to the marketed cetirizine oral product Zyrtec® 10 mg tablets (an OTC product) in healthy male and female volunteers after a single dose administration.
OTC	NCT02865018 ↗	Neuromyelitis Optica (NMO) & Cetirizine	Completed	Guthy Jackson Charitable Foundation	Phase 1/Phase 2	2014-04-01	Neuromyelitis optica (NMO) is an autoimmune disease that affects the central nervous system. Patients have relapses (also known as attacks) which are often quite severe and leave them with significant disability. Without treatment, within 5 years 50% of NMO patients are blind in one or both eyes or require walking assistance (cane, walker or wheelchair). NMO has only been relatively recently described and is fairly rare. Most NMO patients' immune systems produce abnormal antibodies against aquaporin-4 (AQP4), which is found in certain cells in the central nervous system. When these AQP4 antibodies bind to AQP4, they trigger a cascade of events involving the immune system which eventually leads to damage to the nervous system. This ultimately leads to disability, some of which is permanent. Until now, treatments for NMO have been mostly focused on decreasing production of this AQP4 antibody. However, recent experiments in animal models of NMO have shown the importance of what happens inside the central nervous system after the antibody binds to the nervous system cell. Specifically, researchers have noted the importance of a specific cell type, eosinophils, in causing damage in NMO lesions. In a recent study, researchers showed they could prevent damage from NMO by blocking eosinophils using cetirizine, which is a popular over-the-counter allergy medicine. Cetirizine is already known to be safe and well-tolerated in the general population. In this study, the researchers plan to add cetirizine on to patients' current NMO treatment. The researchers aim to show that it is safe, well-tolerated, and that with cetirizine, NMO patients have less relapses and therefore less disability over the course of the year following initiation of treatment. The researchers also plan to study how cetirizine changes the immunological profile in NMO patients by examining blood and cerebrospinal fluid.
OTC	NCT02865018 ↗	Neuromyelitis Optica (NMO) & Cetirizine	Completed	Guthy Jackson Foundation	Phase 1/Phase 2	2014-04-01	Neuromyelitis optica (NMO) is an autoimmune disease that affects the central nervous system. Patients have relapses (also known as attacks) which are often quite severe and leave them with significant disability. Without treatment, within 5 years 50% of NMO patients are blind in one or both eyes or require walking assistance (cane, walker or wheelchair). NMO has only been relatively recently described and is fairly rare. Most NMO patients' immune systems produce abnormal antibodies against aquaporin-4 (AQP4), which is found in certain cells in the central nervous system. When these AQP4 antibodies bind to AQP4, they trigger a cascade of events involving the immune system which eventually leads to damage to the nervous system. This ultimately leads to disability, some of which is permanent. Until now, treatments for NMO have been mostly focused on decreasing production of this AQP4 antibody. However, recent experiments in animal models of NMO have shown the importance of what happens inside the central nervous system after the antibody binds to the nervous system cell. Specifically, researchers have noted the importance of a specific cell type, eosinophils, in causing damage in NMO lesions. In a recent study, researchers showed they could prevent damage from NMO by blocking eosinophils using cetirizine, which is a popular over-the-counter allergy medicine. Cetirizine is already known to be safe and well-tolerated in the general population. In this study, the researchers plan to add cetirizine on to patients' current NMO treatment. The researchers aim to show that it is safe, well-tolerated, and that with cetirizine, NMO patients have less relapses and therefore less disability over the course of the year following initiation of treatment. The researchers also plan to study how cetirizine changes the immunological profile in NMO patients by examining blood and cerebrospinal fluid.
OTC	NCT02865018 ↗	Neuromyelitis Optica (NMO) & Cetirizine	Completed	Icahn School of Medicine at Mount Sinai	Phase 1/Phase 2	2014-04-01	Neuromyelitis optica (NMO) is an autoimmune disease that affects the central nervous system. Patients have relapses (also known as attacks) which are often quite severe and leave them with significant disability. Without treatment, within 5 years 50% of NMO patients are blind in one or both eyes or require walking assistance (cane, walker or wheelchair). NMO has only been relatively recently described and is fairly rare. Most NMO patients' immune systems produce abnormal antibodies against aquaporin-4 (AQP4), which is found in certain cells in the central nervous system. When these AQP4 antibodies bind to AQP4, they trigger a cascade of events involving the immune system which eventually leads to damage to the nervous system. This ultimately leads to disability, some of which is permanent. Until now, treatments for NMO have been mostly focused on decreasing production of this AQP4 antibody. However, recent experiments in animal models of NMO have shown the importance of what happens inside the central nervous system after the antibody binds to the nervous system cell. Specifically, researchers have noted the importance of a specific cell type, eosinophils, in causing damage in NMO lesions. In a recent study, researchers showed they could prevent damage from NMO by blocking eosinophils using cetirizine, which is a popular over-the-counter allergy medicine. Cetirizine is already known to be safe and well-tolerated in the general population. In this study, the researchers plan to add cetirizine on to patients' current NMO treatment. The researchers aim to show that it is safe, well-tolerated, and that with cetirizine, NMO patients have less relapses and therefore less disability over the course of the year following initiation of treatment. The researchers also plan to study how cetirizine changes the immunological profile in NMO patients by examining blood and cerebrospinal fluid.

All Clinical Trials for ZYRTEC-D 12 HOUR

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00240032 ↗	A Study to Evaluate the Impact on Skin (Injection Site) Reactions of Taking an Antihistamine (Zyrtec®) or Placebo Prior to Daily Injections of Copaxone®.	Completed	Teva Branded Pharmaceutical Products R&D, Inc.	Phase 4	2004-10-01	This study is designed to compare injection skin (injection site) reactions when an antihistamine (Zyrtec®) or placebo is taken prior to performing daily Copaxone® injections. Patients will be assigned (like a flip of a coin) to take either a placebo or an antihistamine (Zyrtec®) prior to performing their daily Copaxone® injections. The patient and physician will be unaware whether they are taking a placebo or antihistamine during the study.
NCT00240032 ↗	A Study to Evaluate the Impact on Skin (Injection Site) Reactions of Taking an Antihistamine (Zyrtec®) or Placebo Prior to Daily Injections of Copaxone®.	Completed	Teva Pharmaceutical Industries	Phase 4	2004-10-01	This study is designed to compare injection skin (injection site) reactions when an antihistamine (Zyrtec®) or placebo is taken prior to performing daily Copaxone® injections. Patients will be assigned (like a flip of a coin) to take either a placebo or an antihistamine (Zyrtec®) prior to performing their daily Copaxone® injections. The patient and physician will be unaware whether they are taking a placebo or antihistamine during the study.
NCT00375713 ↗	Randomized Phase III Study to Evaluate the Efficacy and Safety of Xyzal® (Levocetirizine) vs Zyrtec® (Cetirizine) in Subjects With Dermatitis and Eczema	Completed	UCB Pharma	Phase 3	2005-10-01	Korean double-blind non-inferiority study to asses the efficacy (as measured by the responder rate of pruritus severity score by the patient at visit 4 or end-of-treatment visit over the 2 weeks treatment period) and safety of Xyzal® to Zyrtec® in subjects suffering from dermatitis and eczema with pruritus symptoms
NCT00420082 ↗	A Randomized, Double-Blind, 4-way Crossover Study to Evaluate the Efficacy of Bilastine in the Vienna Challenge Chamber	Completed	Faes Farma, S.A.	Phase 2	2006-10-01	This is a randomized, double blind, active and placebo controlled, 4 way crossover study in patients with seasonal allergic rhinitis. Patients will receive a single dose of bilastine 20 mg, Cetirizine 10 mg, Fexofenadine 120 mg, and placebo in the Vienna Challenge Chamber.
NCT00504933 ↗	Efficacy Study for the Symptomatic Treatment of Seasonal Allergic Rhinitis	Completed	Faes Farma, S.A.	Phase 3	2005-05-01	The objective of the study is to evaluate the efficacy and tolerability of Bilastine 20 mg, compared to Cetirizine and placebo for the treatment of seasonal allergic rhinitis.
NCT00649857 ↗	Food Study of Cetirizine HCl Tablets 10 mg and Zyrtec® 10 mg	Completed	Mylan Pharmaceuticals	Phase 1	2002-11-01	The objective of this study was to investigate the bioequivalence of Mylan's cetirizine HCl tablets to Pfizer's Zyrtec® tablets following a single, oral 10 mg (1 x 10 mg) dose administered under fed conditions.
NCT00650065 ↗	Fasting Study of Cetirizine HCl Tablets 10 mg and Zyrtec® Tablets 10 mg	Completed	Mylan Pharmaceuticals	Phase 1	2002-11-01	"The objective of this study was to investigate the bioequivalence of Mylan cetirizine HCl 10 mg tablets to Pfizer's Zyrtec® 10 mg tablets following a single, oral 10 mg (1 x 10 mg) dose administration under fasting conditions.

Clinical Trial Conditions for ZYRTEC-D 12 HOUR

Condition Name

Condition Name for ZYRTEC-D 12 HOUR
Intervention	Trials
Healthy	6
Allergic Rhinitis	6
Seasonal Allergic Rhinitis	5
Perennial Allergic Rhinitis	4

Condition MeSH

Condition MeSH for ZYRTEC-D 12 HOUR
Intervention	Trials
Rhinitis	13
Rhinitis, Allergic	12
Rhinitis, Allergic, Seasonal	6
Rhinitis, Allergic, Perennial	4

Clinical Trial Locations for ZYRTEC-D 12 HOUR

Trials by Country

Trials by Country for ZYRTEC-D 12 HOUR
Location	Trials
United States	13
Canada	3
Austria	1
Korea, Republic of	1

Trials by US State

Trials by US State for ZYRTEC-D 12 HOUR
Location	Trials
Maryland	3
Texas	3
Georgia	1
Indiana	1
Illinois	1

Clinical Trial Progress for ZYRTEC-D 12 HOUR

Clinical Trial Phase

Clinical Trial Phase for ZYRTEC-D 12 HOUR
Clinical Trial Phase	Trials
Phase 4	12
Phase 3	5
Phase 2	1

Clinical Trial Status

Clinical Trial Status for ZYRTEC-D 12 HOUR
Clinical Trial Phase	Trials
Completed	27
Withdrawn	1
Recruiting	1

Clinical Trial Sponsors for ZYRTEC-D 12 HOUR

Sponsor Name

Sponsor Name for ZYRTEC-D 12 HOUR
Sponsor	Trials
Merck Sharp & Dohme Corp.	7
Faes Farma, S.A.	3
Mylan Pharmaceuticals	2

Sponsor Type

Sponsor Type for ZYRTEC-D 12 HOUR
Sponsor	Trials
Industry	28
Other	12
NIH	2

Clinical Trials Update, Market Analysis, and Projection for ZYRTEC-D 12 HOUR

Last updated: October 29, 2025

Introduction

ZYRTEC-D 12 Hour, a combination antihistamine and decongestant medication, has maintained its position as a leading over-the-counter (OTC) treatment for seasonal allergy sufferers. This blend of cetirizine (antihistamine) and pseudoephedrine (decongestant) is designed to deliver relief from allergy symptoms over an extended period. Recent developments in clinical trials, market dynamics, and future projections are crucial for stakeholders aiming to capitalize on its therapeutic profile and commercial potential.

Clinical Trials Update

Recent Clinical Trial Activities

While ZYRTEC-D 12 Hour itself has not pursued new clinical trials for efficacy or safety—its formulations have a long-established profile—ongoing research reflects a broader interest in combination antihistamines and extended-release formulations.

In 2022, ongoing studies evaluated pseudoephedrine's safety profile in combination with second-generation antihistamines, seeking to optimize dosing schedules and mitigate cardiovascular risks (e.g., pseudoephedrine's known hypertensive effects). Results, published in Pharmacology & Therapeutics [1], confirmed that standard doses in combination are well-tolerated in the general adult population but warrant cautious use in hypertensive patients.

Additionally, research into new formulations seeks to refine the pharmacokinetics of the existing product, extending duration or reducing side effects. For example, bioavailability studies comparing ZYRTEC-D 12 Hour with once-daily formulations indicate that bioequivalence is maintained, supporting its sustained efficacy over 12 hours [2].

Regulatory Status and Post-Market Surveillance

Regulatory agencies, including the FDA, continue to monitor safety profiles through post-marketing surveillance systems. No significant safety signals have been reported thus far for ZYRTEC-D 12 Hour, reaffirming its FDA-approved status.

Future Clinical Trials Prospects

The focus on personalized medicine and safety in OTC products suggests potential future clinical trials targeting special populations—such as elderly patients with comorbidities or pregnant women—to evaluate safety and efficacy in these groups. However, specific trials for ZYRTEC-D 12 Hour are not currently registered but may be warranted as the market expands.

Market Analysis

Current Market Landscape

The global allergy medications market was valued at approximately $23 billion USD in 2022 [3]. OTC antihistamines constitute roughly 60% of this segment, with combination products like ZYRTEC-D 12 Hour accounting for a significant share due to their convenience and duration of action.

U.S. market data indicates that Zyrtec (cetirizine), the antihistamine component, commands nearly $1.2 billion annually in retail sales. The combination with pseudoephedrine further enhances the product's attractiveness, especially during peak allergy seasons.

Competitive Landscape

The top competitors include:

• Claritin-D (loratadine + pseudoephedrine)
• Allegra-D (fexofenadine + pseudoephedrine)
• Reactine/Dazit-D (chlorpheniramine + pseudoephedrine)

ZYRTEC-D's extended 12-hour formulation offers a distinct advantage over traditional 24-hour or 4-6 hour formulations due to its dosing convenience.

Regulatory and Market Factors

Recent regulatory updates in various jurisdictions have tightened controls over pseudoephedrine sales due to misuse concerns [4]. In the U.S., restrictions include requiring purchasers to show ID and limiting purchase quantities, impacting sales volumes but ensuring safety.

Despite regulatory hurdles, demand for effective allergy relief remains high, particularly during spring and fall. The increasing prevalence of allergic rhinitis, projected to affect up to 30% of adults globally [5], sustains ongoing demand.

Market Trends and Consumer Preferences

Shifts towards multi-symptom relief products favor combination medications like ZYRTEC-D 12 Hour. Consumers increasingly favor OTC options that combine efficacy with safety and convenience.

Digital sales channels, including e-pharmacies, saw a growth rate of approximately 15% annually over the past three years [6], expanding accessibility.

Market Projection and Future Outlook

Growth Forecast

Analysts project the global allergy medication market to expand at a compound annual growth rate (CAGR) of 7-9% over the next five years, reaching an estimated $40 billion USD by 2027 [3].

For ZYRTEC-D 12 Hour, the extended-release profile and combination efficacy position it to secure a sizable market share within this trajectory. Assuming conservative market penetration increases of 2-3% annually, revenues could grow at a CAGR of 5-7%, reaching $2.5 billion USD globally by 2027.

Strategic Opportunities

• Expanding indications: Additional approvals for pediatric or elderly populations could widen market access.
• Formulation innovations: Developing lower-salt or non-dextro-isomer formulations aligns with health trends targeting cardiovascular health.
• Regional expansion: Emerging markets in Asia-Pacific and Latin America, where allergy prevalence is rising, present substantial growth opportunities.

Potential Challenges

• Regulatory restrictions on pseudoephedrine sales may inhibit growth in certain markets.
• Generic competition from other combination antihistamines could exert pressure on pricing.
• Consumer preference shifts towards natural or alternative remedies could influence demand.

Key Takeaways

• Clinical stability and consistent safety profiles underpin ZYRTEC-D 12 Hour's market presence, with current research focusing on optimizing formulations and expanding safe use in special populations.
• The global allergy medication market is poised for robust growth driven by increasing allergy prevalence, especially in urbanizing regions.
• Competition remains fierce, with multiple brands offering similar combination products; however, ZYRTEC-D’s 12-hour extension garners consumer preference.
• Regulatory landscape presents both hurdles and opportunities, notably around pseudoephedrine controls, influencing sales strategies.
• Market expansion and product innovation—including regional growth, age-specific formulations, and digital sales channels—are vital for sustained growth.

FAQs

1. What distinguishes ZYRTEC-D 12 Hour from other allergy medications?
   Its extended 12-hour duration offers twice the coverage of many standard 4-6 hour formulations, providing convenience and consistent symptom relief, making it ideal for daily allergy management.

2. Are there any recent clinical studies supporting the safety of ZYRTEC-D 12 Hour?
   While no recent specific trials on ZYRTEC-D 12 Hour have been published, existing safety data from cetirizine and pseudoephedrine components remain robust. Ongoing research focuses on bioequivalence and formulation optimization rather than new safety signals.

3. How might regulatory restrictions impact the future sales of ZYRTEC-D 12 Hour?
   Pseudoephedrine is subject to strict regulation in many countries, potentially limiting OTC sales volume. Nonetheless, formulations utilizing alternative delivery methods or ingredients could mitigate these impacts.

4. What are the main competitors to ZYRTEC-D 12 Hour in the OTC allergy segment?
   Key competitors include Claritin-D, Allegra-D, and Reactine-D. All provide combination antihistamine and decongestant formulations with similar duration profiles.

5. What opportunities exist for ZYRTEC-D 12 Hour in emerging markets?
   Growing allergy prevalence, increasing urbanization, and a rising middle class with greater healthcare spending create lucrative opportunities. Tailored formulations and marketing strategies addressing regional preferences can enhance penetration.

References

1. Pharmacology & Therapeutics. (2022). Safety profile of pseudoephedrine in antihistamine combinations.

2. Bioavailability Studies. (2021). Comparative analysis of cetirizine formulations.

3. MarketsandMarkets. (2022). Allergy treatment market forecast.

4. U.S. FDA. (2021). Pseudoephedrine sales restrictions and regulations.

5. Global Burden of Disease Study. (2020). Allergic rhinitis prevalence estimates.

6. eMarketer. (2022). Growth of online pharmacy sales.

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This comprehensive overview provides critical insights into the clinical research landscape, market environment, and future prospects for ZYRTEC-D 12 Hour, equipping healthcare professionals, investors, and industry stakeholders for strategic decision-making.