Medi-Span and First Databank (FDB) are two of the most widely utilized drug compendia publishers. Both publishers include drug attributes and pricing values. Each publisher also has a unique, proprietary drug identifier that groups products with the same active ingredient, strength, route, and dosage form.
The Generic Product Identifier (GPI) from Medi-Span is 14 characters made up of 7 couplets. FDB has the Generic Sequence Number (GSN) also known as the Clinical Formulation ID or formerly as GCN Sequence Number (GCN Seq No), which is 6 digits in length. FDB also has the GCN (Formulation ID) which is 5 digits, but the GSN is more detailed and will be the focus of this review.
This table highlights some of the differences between the GPI and GSN.
| Attribute | GPI | GSN |
| Hierarchy | Yes | No (see NOTE below) |
| Regular changes | Yes | Few to none |
| Value Limitations | Dosage form couplet | N/A |
| Therapeutic Classifications | 1 per GPI | No (see NOTE below) |
The GPI is setup as a hierarchy, which allows groupings at less specific levels than the active ingredient, strength, route, and dosage form. Here is an example of the GPI hierarchy for Nortriptyline HCL 10mg capsules:
| GPI | Coding | Example |
| 58- | Drug Group | Antidepressants |
| 58-20- | Drug Class | Tricyclic agents |
| 58-20-00 | Drug sub-class | Tricyclic agents |
| 58-20-00-60 | Drug name | Nortriptyline |
| 58-20-00-60-10 | Drug name extension | Nortriptyline HCL |
| 58-20-00-60-10-01 | Dosage form | Nortriptyline HCL Capsule |
| 58-20-00-60-10-01-05 | Strength | Nortriptyline HCL Capsule 10mg |
GPIs may change at any of the hierarchy levels. Each couplet is limited because currently only numbers are used, although letters will be added July 1, 2013 to expand their capabilities. The dosage form couplet at position 11 and 12 of the GPI will be the first to be expanded with the use of letters. A 14 character GPI resides in a single therapeutic classification due to the hierarchy.
The GSN does not utilize a hierarchy. This reduces the need for a GSN to change because there is not a defined sequence to the numbers. The individual digits of the GSN do not have meaning, so the GSN is only limited in its entirety.
| NOTE: The Hierarchal Ingredient Code (HIC) and Enhanced Therapeutic Classification System (ETC) are the separate identifiers that FDB publishes to achieve groupings at the organ system, therapeutic class and subclass, and active ingredient (with and without the salt). |
There is no right or wrong answer on which proprietary identifier to use. The GPI has several built-in features but requires maintenance. The GSN requires the use of additional identifiers but with less maintenance. PHSL has extensive experience with both drug compendia and their respective identifiers as depicted here and here.
Contact PHSL with your questions about Medi-Span and FDB today!