Maryland Code, Insurance § 15-847.1

(1) insurers and nonprofit health service plans that provide coverage for prescription drugs under individual, group, or blanket health insurance policies or contracts that are issued or delivered in the State; and

(2) health maintenance organizations that provide coverage for prescription drugs under individual group contracts that are issued or delivered in the State.

(b)(1) Subject to paragraph (2) of this subsection and § 15-822.1 of this subtitle, an entity subject to this section may not impose a copayment or coinsurance requirement on a prescription drug prescribed to treat diabetes, HIV, or AIDS that exceeds $150 for up to a 30-day supply of the drug.

(2) On July 1 each year, the limit on the copayment or coinsurance requirement on a prescription drug prescribed to treat diabetes, HIV, or AIDS shall increase by a percentage equal to the percentage change from the preceding year in the medical care component of the March Consumer Price Index for All Urban Consumers, Washington Metropolitan Area, from the U.S. Department of Labor, Bureau of Labor Statistics.