Federal guidance on prescription drug coverage under a QHP is found at 45 CFR 156.122. Under that section, an issuer providing EHBs to cover at least the greater of (1) one drug in every United States Pharmacopeia Convention (USP) category and class or (2) the same number of prescription drugs in each category and class as the EHB state benchmark plan. Prior authorization of prescription drugs is permitted as is step therapy. If a recommendation or guideline does not specify the frequency, method, treatment, or setting for the provision of that service, the issuer can use reasonable medical management techniques to determine any coverage limitations.