Last updated: May 25, 2026
Cardizem (diltiazem) suppliers: who manufactures brand and generic doses, and what to buy in US channel
Cardizem is the brand name for diltiazem. In the US, supply is fragmented across branded manufacturer(s) and multiple generic manufacturers of oral solid doses (immediate-release and extended-release). The primary “supplier” in distribution terms is the FDA-listed drug product manufacturer (NDA holder supply chain for the brand) plus the abbreviated-new-drug (ANDA) manufacturers that produce generic Cardizem equivalents.
What matters for procurement and substitution risk is the product’s exact strength and dosage form (IR vs ER), plus the FDA Orange Book listing per strength, and the manufacturing site(s) tied to each ANDA/NDA.
Because your request is “Suppliers for the pharmaceutical drug: cardizem” without dosage form, strength, or jurisdiction, a complete supplier list cannot be produced from first principles without Orange Book and label-by-label manufacturing data.
What does “supplier” mean for Cardizem in practice (NDA vs ANDA vs distributors)?
For business use, “supplier” usually breaks into three layers:
- FDA-labeled drug product manufacturer(s)
- The labeled manufacturer for the branded NDA product or the ANDA generic product.
- API supplier(s)
- Often not disclosed on the US carton/label; it is typically an upstream contract manufacturing and sourcing chain.
- Wholesaler/distributor network
- Wholesale distribution partners are separate from the drug product manufacturer.
Only layer (1) is reliably determinable without guessing, because Orange Book and FDA labeling tie drug product manufacturing to specific NDA/ANDA products by strength and dosage form.
Which companies supply Cardizem in the US (Orange Book labeled manufacturers)?
Answer: Cardizem supply comes from the brand NDA holder’s manufacturing sites plus multiple ANDA manufacturers for diltiazem immediate-release (IR) and diltiazem extended-release (ER) formulations.
But a definitive company list requires the specific Cardizem label family (IR vs ER) and strength, because different strengths can have different ANDA “drug product” manufacturers even for the same active ingredient.
Cardizem brand product coverage (what to map in Orange Book)
- Cardizem (diltiazem hydrochloride): oral, multiple strengths and dosage forms
- Cardizem CD (ER formulation): commonly cited as ER capsule/tablet equivalent family
- Other marketed diltiazem ER products exist under different brand names depending on market history
Generic supply structure for diltiazem
- Diltiazem hydrochloride immediate-release tablets/capsules
- Diltiazem hydrochloride extended-release tablets/capsules
- Manufacturing sites vary by ANDA product
Do Cardizem suppliers differ between immediate-release and extended-release?
Answer: Yes. IR vs ER products generally map to different ANDA formulations and different manufacturing lines/sites, even when the active ingredient is the same diltiazem hydrochloride.
Why IR and ER have different supplier lists
- Distinct dosage technology (release mechanism, excipient system, process steps)
- Different patent and interchangeability histories can drive different ANDA entrants
- Labeling/manufacturing approvals are product-specific in the Orange Book
Who supplies Cardizem in specific strengths (mg) and dosage forms?
Answer: Supplier identity is strength-specific. The Orange Book listing for, for example, diltiazem ER at one mg strength can list one set of manufacturers, while another strength can list different drug product applicants.
Procurement reality
For RFP/RFQ execution, buyer outcomes depend on:
- Exact NDC selected
- ANDA selected for that NDC
- Manufacturing site listed for that product
What are the typical ANDA manufacturers supplying generic diltiazem (Cardizem equivalents)?
Answer: The generic diltiazem market is supplied by multi-product generics manufacturers and segment leaders across cardiovascular therapeutics.
However, producing a complete and accurate supplier roster requires Orange Book lookups per NDC, because:
- Companies can enter and exit supply
- Manufacturing sites can change
- Different ER formats (capsules/tablets) and different salts/strengths can have separate listings
Which API suppliers make diltiazem for Cardizem and its generics?
Answer: API supply chains exist across multiple chemical manufacturers and repackaged intermediates globally, but API names and sites are not consistently disclosed in US drug product labeling.
For “supplier” purposes, the only robust API-level sourcing path is:
- Drug master files (DMFs) and public DMF references
- Vendor qualification records (if you have them)
- GMP audit data from the finished-dose manufacturer
A factual API supplier list for “Cardizem” specifically cannot be produced without Orange Book tied DMF/public filings, and label disclosure is usually insufficient.
How to identify the right Cardizem supplier fast (procurement workflow tied to regulatory data)
Answer: Use a label-to-Orange-Book mapping workflow:
- Identify the exact dosage form (IR tablet vs ER capsule/tablet)
- Identify the strength and NDC
- Retrieve the Orange Book listing for the active ingredient and product
- Record the drug product applicant and labeled manufacturer for that specific listing
- Use the listing’s manufacturing site to qualify procurement
This produces a defensible supplier list for:
- Availability planning
- Substitute risk assessment
- Contracting with confirmed-GMP sites
What generic entry risks exist for Cardizem suppliers (supply and litigation angle)?
Answer: Generic diltiazem has a mature ANDA landscape. Generic entry risk is less about “first-to-file” dynamics and more about:
- Site-specific supply constraints
- Compliance events affecting a given manufacturer’s NDC
- Switching approvals or changes to manufacturing sites
A structured “Paragraph IV risk” and settlement-driven view is generally tied to product-specific patent estates and specific Orange Book-listed patents, which also requires dosage form and strength selection to avoid mixing unrelated diltiazem formulations.
Key Takeaways
- “Cardizem suppliers” in the US must be defined by dosage form and strength, because IR and ER have different ANDA and manufacturing lineups.
- The only defensible supplier list for procurement is the one built from Orange Book listings mapped to the exact NDC for each strength.
- Brand and generic supply are not interchangeable at the manufacturer level; NDC-level mapping is required.
FAQs
- What companies manufacture Cardizem CD (diltiazem extended-release) in the US?
- Which Cardizem NDCs map to which ANDA drug product applicants and labeled manufacturers?
- Are Cardizem IR and Cardizem ER supplied by the same manufacturers?
- How do I confirm the manufacturing site for a specific Cardizem strength and NDC?
- What manufacturing quality or supply disruptions most often affect generic diltiazem availability?
References (APA)
- US Food and Drug Administration. Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/
