How to read an NDC

Three numbers, not one

Every drug product sold in the United States carries a National Drug Code. It looks like one number and it is three, separated by hyphens. This site holds 1,260 product codes and 2,081 package codes underneath them.

The pattern is labeller-product-package. On a shelf you usually see the full three-segment code. In FDA's directory, and throughout this site, a product is identified by the first two segments only, because the third one changes with the pack size while the medicine does not.

The first segment: who put its name on it

The first four or five digits are the labeller code, which FDA assigns to a company. Every product that company lists begins with the same digits. 157 labeller codes appear in this dataset.

The labeller is whoever put its name on the package, and that is often not the manufacturer. A supermarket chain, a distributor and a contract manufacturer can each hold a listing for what is physically the same lozenge, each with its own labeller code. That is why the labeller index and the brand index are separate things here.

The second segment: which formulation

The next three or four digits identify a specific product from that labeller: a specific active ingredient at a specific strength in a specific dosage form. Change the strength and you change this segment. Change the flavour and, usually, you also change it, because FDA treats a differently flavoured product as a different listing.

This is the segment that does the work. It is why the product index has 1,260 rows and not 438.

The third segment: which box

The last one or two digits identify the pack. A 20-count bag and a 90-count tub of the identical lozenge share a product code and differ only here. Each product page on this site lists every package code filed against it, with the description the labeller wrote, which is where you find out that a carton contains three containers of forty.

What an NDC does not tell you

It is a registration number, not a quality mark and not an approval. FDA says so itself: assigning an NDC does not mean FDA has approved the product. A listing exists because a company filed it.

• It does not tell you the product is on sale. 76 listings here are bulk or further-processing records that no shop ever stocks.
• It does not tell you the product is current. Every listing carries an expiration date for the listing itself, which this site shows and does not use to hide anything.
• It does not tell you the product is over the counter. 3 of the products here are prescription only, and they are flagged as such.