Final answer:
In the FDA's Orange Book, an "A" rating indicates a drug is therapeutically equivalent to other equivalents, whereas a "B" rating indicates it is not.
Step-by-step explanation:
When searching the Orange Book for a therapeutic equivalent, anything that starts with an "A" indicates that the drug product is considered to be therapeutically equivalent to other pharmaceutically equivalent products. In contrast, anything starting with a "B" signifies that the drug product is not considered to be therapeutically equivalent to other pharmaceutically equivalent products. The Orange Book's rating system is critical for healthcare providers when they are making decisions about prescribing generic medications.