Which companies make “E56” quetiapine?
“E56” isn’t a manufacturer name on its own; it typically refers to a product/pack code or local labeling used for a specific quetiapine listing (for example, a particular strength and dosage form). Which manufacturer you get depends on the exact E56 entry (strength, tablet vs. extended-release, and country/market).
To identify the manufacturer, you need the full product details from the box/blister or the listing page, especially:
- strength (e.g., 25 mg, 50 mg, 100 mg, 200 mg, etc.)
- immediate-release vs. extended-release (XR/Prolonged)
- dosage form (tablet)
- the country/market you’re using
How to tell which manufacturer you have in practice
Check the packaging for:
- “Manufacturer” or “Marketing authorisation holder”
- the “company name” near the batch/lot info
- the trade name (if any), not just the E56 code
- NDC/ATC/MA number equivalents used locally (varies by country)
If you share the exact strength and whether it’s extended-release, plus the country, I can help narrow down the likely manufacturer names tied to that specific listing.
Are there multiple quetiapine manufacturers for the same dose/strength?
Yes. Quetiapine tablets are made by multiple companies across different markets, often with several generic or brand suppliers. Even when the active ingredient and strength match, different suppliers can market different versions (immediate vs. extended-release), or use different excipients and packaging, which is why the manufacturer can change.
What to compare across manufacturers (so you get the right product)
Patients often run into problems when switching between:
- immediate-release vs. extended-release formulations
- different strengths
- different brands/generics that are not the same release profile
When substituting, confirm the release type and strength match what your prescriber intended.
If you paste the exact text from the box (manufacturer line + strength + “XR/Prolonged” wording), I’ll list the manufacturers that correspond to that exact E56 quetiapine listing.