MI HB4358

Prohibits insurers offering qualified health plans with prescription drug coverage from removing drugs from formularies or adding utilization restrictions unless specific conditions are met, including FDA safety actions, manufacturer discontinuance, drug reclassification, or price increases of 10% annually or 20% over three years.

Allows formulary changes based on clinically accepted medical best practices, newly approved drugs with clinical advantages, generic/biosimilar alternatives, or over-the-counter reclassification.

Requires insurers to provide affected insureds 90 days' written notice before removing drugs from formulary, including information about alternative medication options.

Mandates that if a prescriber determines a removed or reclassified drug is medically necessary, insurers must treat it as if the change did not occur for that individual during the plan year.

Preserves insurers' ability to add new drugs to formularies mid-year and permits generic substitutions consistent with Michigan pharmacy law; provision is subject to federal law.