Several factors can contribute to why some medications are not covered by insurance:
Formulary Design. Insurance companies maintain a formulary, which is a list of medications they cover. Medications not included in this list might not be covered due to the insurer's decision to prioritize certain drugs based on cost-effectiveness, safety, and therapeutic value.
Cost. Some medications are excluded from coverage due to their high cost. Insurers may opt to exclude certain expensive drugs to control expenses and keep premiums manageable for their policyholders.
Clinical Necessity. Insurers might determine that certain medications are not deemed clinically necessary for most individuals, especially if alternative treatments with similar efficacy are available at a lower cost.
Generic Availability. Insurance companies often favor generic medications over brand-name equivalents due to their lower cost. Insurers might exclude coverage for the brand-name version if a generic version is available.
Prior Authorization. Certain medications require prior authorization from the insurance company before coverage is approved. It might not be covered if the authorization process is not completed or the medication does not meet the insurer's criteria.
Experimental or Off-Label Use. Medications still undergoing clinical trials or prescribed for off-label uses (not approved by regulatory authorities) might not be covered due to limited evidence of their effectiveness and safety.
Policy Limitations. Some insurance plans have limitations on coverage for specific conditions or medications. These limitations can be based on the plan's structure, type, or cost.
Changing Formularies. Insurers periodically update their formularies, adding or removing medications based on new clinical evidence, pricing negotiations, and market availability.