Glossary
national drug code
The National Drug Code is the identifier a drug package carries in three segments — labeler, product, package. Labels print it as 10 digits in one of three layouts; billing systems key on an 11-digit padded form.
The National Drug Code (NDC) is the number that identifies a specific drug package in the United States. It has three segments — the labeler code, which FDA assigns to the manufacturer or repackager; the product code, which the labeler assigns to a strength and dosage form; and the package code, which distinguishes the bottle size or the unit-dose blister. The labeler and the product together describe the drug; the package code is what makes the NDC a package identifier rather than a drug identifier.
An NDC is printed on the label as 10 digits in one of three layouts — 4-4-2, 5-3-2 or 5-4-1 — and billed in exactly one, the 11-digit 5-4-2 form, made by padding the short segment with a leading zero. That padding step is the arithmetic the exam tests: read the label's layout, find the segment that is one digit short, add the zero there, and rejoin as 5-4-2.
Three consequences follow. One drug has many NDCs — every labeler, every package size and every repackager gets its own — so an NDC identifies a package and not a molecule. The NDC is not the price and not the therapeutic substitute: two products with different NDCs may be interchangeable, and two with the same drug name may not be. And the code is a technical identifier with its own FDA rule; the labeler/product/package structure is governed by 21 CFR 207.33, which FDA revised in a final format rule published March 5, 2026. When a claim rejects, the NDC is usually the first field to check.
Taught in
Related terms
- DEA number — A DEA number is the nine-character registration identifier the DEA issues to a prescriber or a pharmacy: two letters, then seven digits. The second letter is the surname initial, and the last digit is a check digit.
- beyond-use date — A beyond-use date is the last date a prepared or opened medication may be used. It is set by the pharmacy from USP standards, not by the manufacturer's expiration date on the stock bottle.
- days supply — Days supply is how long a dispensed quantity is meant to last: the quantity divided by the amount taken per day. It comes from the sig, not from the size of the package.
Source: PTCB — PTCE Content Outline, effective January 6, 2026 (the KA 1.2 statement "Therapeutic duplications", the KA 2.2 and 2.3 statements on controlled substances and prescription requirements, the KA 4.3 and 4.4 statements on NDC, lot, expiration and returns, and the KA 3.1/3.2 error-prevention statements, quoted verbatim); FDA label and NDC data read through openFDA and DailyMed; ISMP (the high-alert medication definition and the error-prone abbreviation list); USP <795> and <797>; the DEA Pharmacist's Manual (outline accessed 2026-10-03, verbatim; every fact below restates this course's own guides, which carry the per-source citations on their own pages (FDA, ISMP, USP and DEA each publish on its own schedule))