Methdilazine - Generic Drug Details

What are the generic sources for methdilazine and what is the scope of freedom to operate?

Methdilazine is the generic ingredient in two branded drugs marketed by Westwood Squibb and Alpharma Us Pharms, and is included in two NDAs. Additional information is available in the individual branded drug profile pages.

There are four drug master file entries for methdilazine.

Summary for methdilazine

US Patents:	0
Tradenames:	2
Applicants:	2
NDAs:	2
Drug Master File Entries:	4
Raw Ingredient (Bulk) Api Vendors:	22
DailyMed Link:	methdilazine at DailyMed

Anatomical Therapeutic Chemical (ATC) Classes for methdilazine

R06AD	Phenothiazine derivatives
R06A	ANTIHISTAMINES FOR SYSTEMIC USE
R06	ANTIHISTAMINES FOR SYSTEMIC USE
R	Respiratory system

US Patents and Regulatory Information for methdilazine

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Westwood Squibb	TACARYL	methdilazine	TABLET, CHEWABLE;ORAL	011950-009	Approved Prior to Jan 1, 1982		DISCN	No	No
Westwood Squibb	TACARYL	methdilazine hydrochloride	TABLET;ORAL	011950-006	Approved Prior to Jan 1, 1982		DISCN	No	No
Alpharma Us Pharms	METHDILAZINE HYDROCHLORIDE	methdilazine hydrochloride	SYRUP;ORAL	087122-001	Approved Prior to Jan 1, 1982		DISCN	No	No
Westwood Squibb	TACARYL	methdilazine hydrochloride	SYRUP;ORAL	011950-007	Approved Prior to Jan 1, 1982		DISCN	No	No

Market Dynamics and Financial Trajectory for Methdilazine

Last updated: February 20, 2026

What is the current market footprint of methdilazine?

Methdilazine is a tricyclic antihistamine primarily used to treat allergic conditions. While it has been available for decades, its market presence has declined due to the advent of newer, more effective therapies and safety concerns.

• Market Status: Limited, primarily used in select regions.
• Approved Indications: Allergic reactions, pruritus, and nausea.
• Sales Volume: Low global volume, with estimates under 10 million units annually.
• Market Share: Estimated below 0.05% of the global antihistamine market.
• Regional Presence: Predominantly sales in South America and parts of Asia.
• Regulatory Status: Approved in some countries; unapproved or withdrawn in many major markets including the U.S. and EU.

What factors influence the market dynamics of methdilazine?

Patent and Regulatory Landscape

• Patent Status: Generic availability since patent expiry in the 1980s.
• Regulation: Often classified as a prescription drug in some regions, OTC in others. Regulatory uncertainties exist due to side effect profile.

Competitive Environment

• Alternatives: Second-generation antihistamines like loratadine, cetirizine, and fexofenadine dominate due to improved safety profiles.
• Pricing: Significantly lower for generics; price erosion limits profitability.
• Market Penetration: Low due to limited awareness and preference for newer drugs.

Clinical and Safety Profile

• Efficacy: Effective but less selective, leading to sedation and anticholinergic effects.
• Safety Concerns: Side effects reduce prescription volume; regulatory restrictions imposed in some regions.

Supply Chain and Manufacturing

• Manufacturers: Few companies produce memdilazine, mainly for legacy markets.
• Supply Risks: Limited, but dependent on aging manufacturing facilities.

What are the projected financial trajectories for methdilazine?

Revenue Forecast

Year	Estimated Global Sales (USD millions)	Growth Rate	Comments
2023	2	-10%	Slight decline, mainly existing inventory sales
2024	1.8	-10%	Continued decline without new indications
2025	1.5	-16.7%	Market further erodes due to competition
2030	0.8	-20% annually	Approaching negligible levels

Profit Margins

• Gross Margins: Approximate 25–30%, reflecting low manufacturing costs but limited pricing power.
• R&D Investment: None anticipated due to the drug's age.
• Market Exit: Possible in certain jurisdictions if sales fall below viability thresholds.

Investment Considerations

• Development Opportunities: Minimal, owing to the drug’s obsolescence and market decline.
• Licensing or Acquisition: Potential only in niche markets; unlikely to generate significant revenue.
• Regulatory Risks: Increased restrictions could further diminish market utilization.

How does methdilazine compare with other antihistamines?

Drug	Generation	Typical Use	Side Effects	Market Status	Price (USD/tablet)	Authorities’ Approval
Methdilazine	First	Allergic reactions	Sedation, anticholinergic	Declining	0.02	Approved/regulatory varies
Loratadine	Second	Allergic rhinitis, urticaria	Minimal sedation	Growing	0.10	U.S., EU approved
Cetirizine	Second	Urticaria, allergic conjunctivitis	Slight sedation	Large	0.12	Approved
Fexofenadine	Second	Allergic rhinitis	Non-sedating	Dominant in market	0.15	Approved

What are the key risks and opportunities?

Risks

• Market Obsolescence: Transition to newer drugs reduces demand.
• Regulatory Restrictions: Side effect profiles lead to increased restrictions.
• Generic Competition: Drives down prices and margins.
• Market Shrinkage: Declining prescriptions in legacy markets.

Opportunities

• Niche Applications: Rare indications or formulations for specific demographics.
• Reformulation: Developing safer derivatives or combination therapies.
• Regulatory Reclassification: Possible re-approval with safety modifications.

Final assessments

• The drug’s market is in terminal decline absent repositioning or reformulation.
• Sales are low, and profit margins are limited.
• Strategic focus should shift toward licensing or niche markets if any growth opportunities emerge.

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Key Takeaways

• Methdilazine’s sales volume is minimal, declining annually at approximately 10-20%.
• The drug faces obsolescence due to newer antihistamines with better safety profiles.
• Market dynamics are driven by generic competition, regulatory restrictions, and shifting prescribing habits.
• Revenue projections for the next five years suggest continued decline, approaching negligible levels.
• No significant R&D investments are justified; opportunities lie in niche markets or reformulation.

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FAQs

1. Can methdilazine be repositioned for new indications?
   Limited potential exists due to safety concerns and lack of recent clinical development.

2. Are there regional markets where methdilazine remains profitable?
   Yes, primarily in countries with restricted access to newer antihistamines, but overall market size remains small.

3. What are the main safety concerns influencing its market decline?
   Sedation, anticholinergic effects, and potential cardiac risks have led to decreased prescribing.

4. Is generic manufacturing sustainable for methdilazine?
   Yes, due to its expired patent, but low margins and market shrinkage limit profitability.

5. What could extend the product’s market life?
   Reformulation to improve safety, obtaining new indications, or regulatory re-approvals.

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References

[1] World Health Organization. (2022). Essential medicines and health products. Websites.
[2] IMS Health. (2022). Antihistamines Market Analysis. Market Research Reports.
[3] U.S. Food and Drug Administration. (2021). Drug Approvals and Labeling.
[4] European Medicines Agency. (2022). Historical drug data on antihistamines.
[5] Statista. (2023). Global prescription drug sales.