Fioricet contains: 325 mg of acetaminophen (APAP), 50 mg of butalbital, and 40 mg of caffeine.
New capsule reformulation of Fioricet contains: 300 mg of acetaminophen (APAP), 50 mg of butalbital, and 40 mg of caffeine.
Fiorinal contains: 325 mg of aspirin (ASA), 50 mg of butalbital, and 40 mg of caffeine.
The only difference between these two is the aspirin in Fiorinal vs acetaminophen in Fioricet.
Exceptions from the scheduling have been made if the drug meets the requirements of section 811(g) (3) (A) of the Controlled Substances Act. The exemption requires that one of the active ingredients be a non-narcotic controlled substance and one of the others be a non-scheduled compound. The potential for abuse is decreased if a sufficient amount of a non-controlled substance (e.g., aspirin or acetaminophen) is added.
According to the FDA, the issue boils down to a specific ratio of aspirin or acetaminophen to butalbital. Fiorinal® is required to have at least 188 mg of aspirin for every 15 mg of butalbital (188:15) to meet CSA exemption.
The ratio needed for Fioricet® is 70 mg of acetaminophen for every 15 mg of butalbital (70:15).
These ratios were based on what the FDA believed were adequate amounts of nonnarcotic to reduce the abuse potential of butalbital.