Last updated: May 21, 2026
Executive summary
- Chlor-Trimeton is the brand name of chlorpheniramine maleate, a first-generation H1 antihistamine used for allergic rhinitis and related histamine-mediated symptoms.
- Because chlorpheniramine is an older, non-oncology small molecule with long-established generic availability, market exposure is driven by formulation strength, dosage form, label scope, and payer/OTC positioning rather than patent-protected “new chemical entity” development.
- Clinical-trial activity for chlorpheniramine is limited to niche studies (often comparative, safety, pediatric formulations, or pharmaceutic/formulation work) rather than large phase 3 programs for novel indications.
- Commercial trajectory is steady but price-compression sensitive: branded share is typically constrained by generic chlorpheniramine, with growth dependent on OTC channel dynamics and product reformulations that do not materially change the active ingredient.
What is CHLOR-TRIMETON (chlorpheniramine maleate) and what indications does it have?
Quick answer: CHLOR-TRIMETON is chlorpheniramine maleate, an H1 antihistamine. It is used for symptomatic relief of allergic rhinitis and other allergic conditions that benefit from first-generation antihistamine activity.
How does chlorpheniramine work
Chlorpheniramine is a first-generation, centrally acting antihistamine that blocks histamine H1 receptors, reducing symptoms such as sneezing, itching, and rhinorrhea. The first-generation class is associated with sedation relative to many second-generation antihistamines.
Common labeled uses
Across US and international labeling, chlorpheniramine is used for:
- Allergic rhinitis symptoms
- Upper respiratory allergy symptoms
- Histamine-mediated allergic symptoms depending on specific product labeling (strength and dosage form dependent)
What clinical trials are ongoing or recently completed for chlorpheniramine maleate?
Quick answer: Trial volume is low and the dataset skews toward comparative symptom-control, safety/tolerability, pediatric or formulation/PK studies, and older comparative trials rather than late-stage NDA-style development.
Clinical development pattern for mature first-generation antihistamines
For mature, off-patent actives like chlorpheniramine:
- Sponsor participation concentrates on formulation work (e.g., child-appropriate dosing, taste-masking, extended release if applicable).
- Studies often use endpoints tied to symptom scores, time-to-relief, and sedation-related measures.
- Registrational phase 3 trials for new indications are uncommon unless a manufacturer pursues a distinct combination product or a new delivery format with a differentiated regulatory path.
What to expect from trial designs
Common features in chlorpheniramine trial protocols include:
- Randomized, controlled, single-dose or short-duration multiple-dose comparisons versus placebo or alternative antihistamines
- Safety assessments focused on somnolence, anticholinergic effects, and adverse event rates
- PK/PD sub-studies when formulation differences are the core variable
How does CHLOR-TRIMETON compare with second-generation antihistamines on efficacy and tolerability?
Quick answer: First-generation chlorpheniramine generally provides symptom relief but has a higher sedation burden versus many second-generation antihistamines (e.g., cetirizine, loratadine, fexofenadine), which affects adherence and OTC market selection.
Commercial impact of class comparison
- In OTC allergic rhinitis, second-generation antihistamines capture more shelf space in many markets due to lower sedation claims.
- Chlorpheniramine maintains a role where cost, symptom specificity, or “older” brand familiarity supports continued sales.
Where chlorpheniramine can still win
Chlorpheniramine products can remain competitive when:
- Pricing is lower than second-generation alternatives
- Payer and formulary preferences support low-cost antihistamines
- Combination products (when present) provide value aligned with consumer needs (for example, multi-symptom cold/allergy products)
What patents protect CHLOR-TRIMETON (chlorpheniramine maleate)?
Quick answer: For the active ingredient chlorpheniramine maleate, current patent protection is generally not the primary driver of market exclusivity because the molecule is mature and widely genericized. Brand-level exclusivity, if any, would have historically expired long ago.
How to frame IP for CHLOR-TRIMETON
For a long-established antihistamine, the realistic IP landscape is typically:
- Old composition-of-matter and salt form patents that have expired
- Possible later patents tied to specific dosage forms, manufacturing processes, or combinations
- Labeling and regulatory exclusivity protections that do not last for generics of an old active ingredient
When does CHLOR-TRIMETON lose exclusivity?
Quick answer: Exclusivity for chlorpheniramine as an active ingredient is effectively long expired. Any remaining exclusivity would be tied to a specific marketed formulation or combination, not to the core molecule.
What is the Orange Book status of chlorpheniramine maleate (CHLOR-TRIMETON)?
Quick answer: Orange Book coverage for chlorpheniramine exists for certain listed products, but for a mature active, most entries are generic or multiple applicant listings, and brand exclusivity is limited.
How strong is the patent estate for CHLOR-TRIMETON and what does it mean for generics?
Quick answer: Patent strength is low for the active ingredient; generic entry risk is high for any unprotected changes. If CHLOR-TRIMETON is protected only via formulation or specific combination patents, generic risk rises when those specific claims are not asserted.
Generic entry scenario
- If only older molecule patents exist, generic products can be marketed broadly.
- If newer formulation or combination patents exist, generic entry depends on whether the generic makes a noninfringing design-around or waits for expiration.
Are there any Paragraph IV challenges for chlorpheniramine maleate products?
Quick answer: Paragraph IV activity is not a meaningful focal point for chlorpheniramine as an active ingredient because generic competition is already entrenched; any challenges would be product-specific and would occur mainly when a distinct, later-listed formulation has remaining protection.
What FDA regulatory status applies to CHLOR-TRIMETON?
Quick answer: CHLOR-TRIMETON is an FDA-regulated drug product. Chlorpheniramine maleate is available as generics, and the brand’s regulatory advantage is not driven by ongoing new exclusivity.
OTC vs Rx positioning
Market access depends on whether the specific strength and dosage form are OTC or Rx in the relevant geography. OTC positioning typically drives volume in allergic symptom seasons.
Market analysis: how big is CHLOR-TRIMETON and what drives demand?
Quick answer: Chlorpheniramine maleate is a mature allergic rhinitis antihistamine with sales driven by seasonal allergy demand, OTC pricing, shelf competition, and consumer preference for first-generation sedation-tolerant products.
Primary demand drivers
- Allergy season length and intensity
- OTC promotional intensity and retailer planogram placement
- Substitution by second-generation antihistamines
- Multi-symptom cold/allergy product bundling (when offered with the active)
Key market constraints
- Price compression from multiple generics
- Lower consumer preference in markets where second-generation “non-drowsy” claims are dominant
- Sedation-related utilization limits (daytime use patterns)
Sales projection: base case, downside, and upside for CHLOR-TRIMETON
Quick answer: For a mature genericized antihistamine, a realistic projection is low-to-flat growth with modest share losses versus second-generation competitors in most scenarios, unless a product revival occurs through channel expansion or combination/formulation differentiation.
Base case (most likely)
- Volume: stable to slightly declining due to continued substitution to second-generation antihistamines
- Price: limited upside due to generic competition
- Net sales: low growth or mild decline
Upside scenario
- Strong OTC channel execution and promotional support
- Differentiated dosage form or combination that reduces direct substitution
- Market-specific labeling or access improvement
Downside scenario
- Increased retailer preference for non-sedating antihistamines
- Further promotional price cuts by generic competitors
- Margins pressured by payer and retailer contract renegotiations
Competitive landscape: what products most directly substitute for chlorpheniramine?
Quick answer: Substitution is primarily within allergic rhinitis antihistamines, with second-generation agents capturing incremental consumer preference due to lower sedation.
Direct competitive set (class substitutes)
- Cetirizine
- Loratadine
- Fexofenadine
- Other OTC antihistamines and combination cold/allergy products
Which strategy best improves CHLOR-TRIMETON commercial outcomes under generic pressure?
Quick answer: Win through packaging, dosage convenience, and combination differentiation rather than relying on active-ingredient exclusivity.
Actionable levers
- Dosage form and dosing convenience (for example, liquid or specific pediatric dosing schemes where feasible)
- Combination positioning for multi-symptom allergy or cold formulations
- Retail channel optimization during peak allergy periods
- Consumer targeting for those seeking cost-effective antihistamine options
Key Takeaways
- CHLOR-TRIMETON (chlorpheniramine maleate) is a mature antihistamine with limited clinical development momentum outside comparative, safety, and formulation-type studies.
- Market growth is constrained by established generics and substitution to second-generation antihistamines.
- Patent-driven exclusivity is not a central commercial driver for the chlorpheniramine active ingredient; differentiation must come from dosage form, combinations, and channel execution.
FAQs
- Is chlorpheniramine maleate still being studied clinically and in what types of trials?
- Does chlorpheniramine face major FDA exclusivity barriers or opportunities compared with second-generation antihistamines?
- What are the most common safety concerns with first-generation antihistamines like chlorpheniramine?
- How do OTC cold/allergy combination products affect chlorpheniramine share versus monotherapy antihistamines?
- What dosing form characteristics most influence adherence for chlorpheniramine in pediatric and adult markets?
References (APA)
- FDA Orange Book. (n.d.). Drug Products Approved for Marketing. U.S. Food and Drug Administration. https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm
- ClinicalTrials.gov. (n.d.). Chlorpheniramine maleate studies. U.S. National Library of Medicine. https://clinicaltrials.gov/
