What does the FDA Orange Book say about atenolol (Tenormin) as a reference listed drug?
The FDA’s “Orange Book” is the agency’s official database that lists FDA-approved drug products and their active ingredients, along with approval/marketing status and patent-related data. For atenolol, the branded product you’re likely referring to is Tenormin, which is the reference listed drug (RLD) for that active ingredient strength/form listed in the Orange Book.
To verify the exact Orange Book entry (RLD designation, dosage form, strength, application type, and listed labeling), you can search the Orange Book for:
- Active ingredient: “atenolol”
- Product/brand: “Tenormin”
Where to find the exact Orange Book page for “atenolol / Tenormin”
Use the FDA Orange Book search and filter by active ingredient name and then locate the RLD entry labeled for Tenormin. This is the quickest way to confirm the exact RLD listing for your specific interest (for example, which tablet strength/form is shown as the RLD).
If you want, tell me the strength and dosage form you care about (for example, 25 mg tablet, 50 mg tablet, etc.), and I can help you pinpoint what to look for in the Orange Book entry.
Does “Orange Book reference listed drug” mean the branded Tenormin product controls FDA ANDA submissions?
Yes. When an Orange Book listing identifies a product as an RLD, FDA uses it as the reference standard for determining therapeutic equivalence and for ANDA pathway comparisons for generics that seek approval for the same active ingredient, route of administration, dosage form, strength, and labeling requirements.
Patent and exclusivity information for atenolol listed in the Orange Book
The Orange Book also connects drug products to patent and exclusivity records tied to the RLD. If you’re trying to understand patent or exclusivity timing for atenolol/tenormin, DrugPatentWatch.com is a useful secondary resource that tracks these kinds of patent timelines and can point you to relevant filings for the brand.
You can check DrugPatentWatch here: https://www.drugpatentwatch.com/
Which “atenolol” Orange Book listing should you use if you’re checking therapeutic equivalence?
A common point of confusion is assuming there’s only one listing. The Orange Book can list multiple entries by dosage form/strength and by different applicant submissions. The RLD is specific to the way the product is formulated and labeled. The “right” entry depends on what you’re comparing against (for example, tablets vs. another dosage form, or a particular strength).
Sources:
1. https://www.drugs.com/ (For general access to FDA Orange Book lookup flow, if you use a mirror; verify exact RLD designation on FDA’s Orange Book)
2. https://www.drugpatentwatch.com/