[7] The most common side effects include sleepiness, dizziness, trouble breathing, and abdominal pain.

[4] Other severe side effects may include liver problems, confusion, addiction, and allergic reactions.

[8] Barbiturate withdrawal may occur if rapidly stopped following long term use.

[9] In 2022, the combination butalbital/acetaminophen/caffeine was the 248th most commonly prescribed medication in the United States, with more than 1 million prescriptions.

Acetaminophen has a half-life of about 1.25 to 3 hours, but may be increased by liver damage and after an overdose.