Medication Formulary

This project is a proof-of-concept for representing medical formularies in FHIR. Formularies are lists of medications covered under a health insurance plan. Several metadata elements are associated with the formularies (and the individual medications) that are important for patients make decisions about which health plan suits their needs for medications.

Formulary Structure

Formularies in the United States are normally published by health insurers on an annual basis, with minor annual updates. There are occasional emergency releases of formularies when a new medication is released to the public or an existing medication is removed from coverage.

Insurers regularly administer multiple health plans and each of those plans may have its own formulary.

Each formulary contains a list of medications. Since not all medications are covered in the same way or at the same price point, each medication has several metadata elements. Most importantly, drugs are placed into tiers that determine the co-pay or co-insurance amounts that they incur. There is not a single, standard set of drug tiers, but most insurers group medications into 3, 4, 5, or 6 tiers. In addition to the drug tier, medications may also list limitations (e.g., quantity limits, step therapy requirements, prior authorization requirements, etc.) that patients covered under the health plan should be aware of.

Formulary Examples

For reference, the following are links to the formularies for several health insurance companies in the United States:

Expected Users

This Implementation Guide is intended for insurers within the United States. Currently, many insurers make their formularies available to patients using PDFs or drug search forms on their websites. Providing formularies using FHIR may allow patients to more easily comparison-shop between plans and could help insurers educate consumers about the differences between various drug tiers/classes.