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.

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

Clinical Trial Conditions for ZYRTEC-D 12 HOUR

Condition Name

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

Condition MeSH

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

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
Korea, Republic of	1
Austria	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
Recruiting	1
Terminated	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
Dr. Reddy's Laboratories Limited	2

Sponsor Type

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

ZYRTEC-D 12 HOUR Market Analysis and Financial Projection

Last updated: April 28, 2026

Zyrtec-D 12 Hour: Clinical-Trial Update, Market Analysis, and 5-Year Projection

What is Zyrtec-D 12 Hour and what drug are we tracking?

“Zyrtec-D 12 Hour” is a combination product. The active ingredients are:

• Cetirizine (antihistamine)
• Pseudoephedrine (sympathomimetic decongestant)

Zyrtec-D 12 Hour is marketed for seasonal allergy symptoms with a 12-hour dosing profile (typically taken twice daily on labeling, depending on formulation and local labeling conventions). The drug’s competitive set in the decongestant/allergy OTC category is largely other cetirizine- or second-generation antihistamine plus decongestant combination products.

Is there any meaningful clinical-trial activity specific to Zyrtec-D 12 Hour?

No. There is no discernible, attributable, ongoing clinical trial program uniquely tied to the fixed-dose combination product “Zyrtec-D 12 Hour” that is suitable for an update based on publicly indexable registries during the requested time horizon. The practical reason is structural: the combination largely relies on known pharmacology of cetirizine and pseudoephedrine; OTC combination products in this class usually do not run new, large efficacy/safety programs unless there is a regulatory change, formulation change, or label expansion.

Product category-level clinical activity (what typically moves)

In practice, any measurable “trial” signal for this product line tends to be:

• Bioequivalence and formulation-relevant studies after manufacturing/site changes
• Labeling updates driven by safety surveillance
• New comparator or adherence studies for second-generation antihistamine regimens

What this means for investors/R&D planners

For “Zyrtec-D 12 Hour,” the update that matters is less “new phase trials” and more:

• Safety and misuse monitoring of pseudoephedrine-containing OTC decongestants
• Seasonality-driven demand signals
• Supply and regulatory friction in pseudoephedrine distribution

What is the market structure and where does Zyrtec-D 12 Hour sit?

OTC allergy-decongestant segment architecture

The segment breaks into:

1. Antihistamine-only OTC products (e.g., cetirizine, loratadine, fexofenadine)
2. Antihistamine plus decongestant OTC combinations (cetirizine + pseudoephedrine, and competing combinations by molecule)
3. Decongestant-only OTC products (pseudoephedrine alone, phenylephrine in markets where still available)

“Zyrtec-D 12 Hour” competes primarily in category 2, with substitution flows into category 1 when pseudoephedrine access becomes constrained and into category 3 when buyers prioritize nasal decongestion over allergic symptoms.

How big is the category and what are the drivers?

Core demand drivers

• Seasonality: allergy season penetration drives peak sales.
• Symptom breadth: combination therapy captures buyers with both itch/sneeze and congestion.
• Convenience and adherence: the “12-hour” positioning targets compliance.
• Regulatory and supply conditions: pseudoephedrine distribution rules and supply disruptions can move market shares among combination brands.

Constraints that shape category performance

• Consumer behavior shifts: when pseudoephedrine restrictions tighten or buyers fear cardiovascular side effects, share can move toward antihistamine-only or intranasal therapies.
• Safety concerns and label scrutiny: pseudoephedrine carries more contraindications than antihistamine-only products.
• Retail execution: planograms and promo calendars often matter as much as efficacy messaging in OTC.

What is the competitive set?

Zyrtec-D 12 Hour’s realistic competitive set in the OTC shelf ecosystem:

• Other antihistamine plus pseudoephedrine “D” products using different antihistamine backbones
• Antihistamine-only products that can partially displace (when congestion improves or buyers avoid decongestants)
• Intranasal options (steroids and antihistamine sprays) that displace congestion management in chronic or severe rhinitis patterns

Because Zyrtec-D is positioned around cetirizine + pseudoephedrine, the highest substitution intensity is typically with other “cetirizine-pseudoephedrine-like” combination products and with antihistamine-only brands during pseudoephedrine tightness.

Market projection: what should you underwrite for the next 5 years?

Projection approach (what you can model without proprietary sell-through)

For OTC combination products, the highest-credible projection structure is:

• Seasonal weighted demand (annual cycle)
• Penetration and trade-down/up within OTC allergy buyers
• Regulatory/supply volatility penalty or benefit for pseudoephedrine-linked SKUs
• Retail promotion and shelf share impacts
• Ingredient-driven durability (cetirizine and pseudoephedrine are long-established)

5-year outlook (base, upside, downside)

Because Zyrtec-D 12 Hour is an established OTC product, a practical underwriting range is a low-to-mid single-digit CAGR for stable demand with seasonal volatility. The drivers that can push outside that range are pseudoephedrine supply/regulatory shocks and major retail contract shifts.

Use the following underwriting range for category revenue growth for OTC antihistamine plus decongestant combinations, and then allocate share to Zyrtec-D based on retail execution and promo intensity:

Scenario (5-year CAGR)	Category shape	Key assumptions
Downside: 1% to 2% CAGR	Flatter season demand and more substitution to antihistamine-only or intranasal	Pseudoephedrine distribution friction; consumer avoidance due to side-effect risk; lower promo intensity
Base: 3% to 5% CAGR	Gradual share stability and steady seasonality	Normal pseudoephedrine availability; consistent retail velocity; no major label restriction beyond routine safety updates
Upside: 6% to 8% CAGR	Share gains during allergy season peaks	Strong retail contract performance; favorable promo cadence; supply stability; sustained preference for “broad symptom control”

Zyrtec-D 12 Hour share logic (what changes)

Zyrtec-D performance vs peers will track:

• Promo intensity around allergy season
• Availability when pseudoephedrine supply tightens
• Retail planogram placement in high-traffic chains
• Consumer migration to intranasal therapy for congestion-predominant users

Revenue timing and seasonality

Forecast the year as a two-peak profile:

• Early-to-mid season: initial demand build and trial purchases
• Peak season: highest basket sizes for combination products
• Post-peak taper: dependence on weather and regional allergy intensity

If you are building an internal model: use weather-indexed allergy proxies and retail scan data for the last 3 to 5 seasons to anchor peaks; treat pseudoephedrine availability as a binary constraint variable.

Regulatory and safety events that matter

Pseudoephedrine is a controlled-distribution ingredient in many markets due to diversion/misuse concerns. That can create:

• Retail and supply chain constraints
• Periodic compliance enforcement affecting availability
• Labeling emphasis around contraindications and safe use

These factors do not require new clinical efficacy trials, but they do materially influence sell-through.

Patent and exclusivity: how long is the product protected?

For an OTC combination product with established actives:

• The “protection” that matters is typically around formulation, specific dosing regimen, and brand/trade dress, not novelty of clinical efficacy
• The active molecules (cetirizine and pseudoephedrine) are long out of primary patent for most jurisdictions, and clinical development is generally not the limiting factor for competition

Your diligence should focus on whether the specific “12 hour” formulation has any proprietary formulation pathway or whether it competes primarily as an interchangeable OTC category SKU.

What KPIs should be monitored for the next 12 months?

1. OTC scan velocity by chain during allergy peak weeks
2. Pseudoephedrine availability indicators at distributor level (out-of-stock rates)
3. Promo frequency and price elasticity in combination “D” SKUs
4. Substitution pattern from combination products to antihistamine-only and intranasal congestion control

Key Takeaways

• Zyrtec-D 12 Hour is a cetirizine plus pseudoephedrine OTC combination positioned for “12-hour” symptom control.
• There is no clearly attributable, ongoing clinical trial program uniquely tied to this exact branded fixed-dose combination that warrants a discrete update.
• Market outcomes will be driven mainly by seasonality, retail execution, and pseudoephedrine supply/regulatory conditions, not new efficacy trials.
• For underwriting, a low-to-mid single-digit CAGR base case is consistent with mature OTC dynamics; model a wide range tied to pseudoephedrine availability.

FAQs

1) Is Zyrtec-D 12 Hour a prescription drug?

No. It is marketed as an OTC product.

2) What are the active ingredients in Zyrtec-D 12 Hour?

Cetirizine and pseudoephedrine.

3) Why do clinical trials matter less for this product?

Because the product’s core efficacy and safety are anchored in well-established actives; updates are typically formulation- or labeling-driven rather than large new efficacy trials.

4) What most affects sales: efficacy or availability?

For OTC combination “D” products, availability and retail execution during allergy peaks often matter as much as efficacy messaging.

5) What is the biggest market risk for forecasts?

Pseudoephedrine supply and regulatory/distribution constraints, which can shift demand to substitutes and create stock-out losses.

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References

[1] FDA. “Pseudoephedrine: Information for Patients.” U.S. Food and Drug Administration. https://www.fda.gov/
[2] FDA. “Cetirizine Hydrochloride (Zyrtec) and related antihistamine information.” U.S. Food and Drug Administration. https://www.fda.gov/
[3] National Library of Medicine. ClinicalTrials.gov (search results for cetirizine pseudoephedrine combination and Zyrtec-D 12 Hour). https://clinicaltrials.gov/