By Edmund Murphy

Last updated: 21 March 2024 & medically reviewed by Dr. Kimberly Langdon

Fioricet is comprised of a mix of different drugs that all have varying effects and stay in the system for different amounts of time.

Key takeaways:

  • The total half-life for Fioricet, that is the length of time it takes for half the drug to be eliminated from the system, is 35 hours.

  • Butalbital has a long half-life and is detectable in blood for roughly 8 days.

  • False-positive results are extremely rare, occurring less than 1% of the time. However, Non-steroidal anti-inflammatory drugs (NSAIDs) such as naproxen and ibuprofen can trigger a false-positive result for butalbital.

How long is Fioricet in your system for?

Fioricet contains three different drugs. Each drug is estimated to stay in your body for a different amount of time.

  • Acetaminophen is eliminated after about 6 to 15 hours

  • Caffeine is eliminated after about 15 hours

  • Butalbital is eliminated after about 7 days

The total half-life for Fioricet, that is the length of time it takes for half the drug to be eliminated from the system, is 35 hours. The onset of Fioricet takes 30-60 minutes before the effects are felt.

Fioricet detection in urine

Most urine drug tests will pick up butalbital use 3–7 days from the last dose.

Fioricet detection in blood

Butalbital has a long half-life and is detectable in blood for roughly 8 days. However, blood tests are not frequently used to detect drug use because they are expensive, time-consuming, and invasive.

Fioricet detection in saliva

Butalbital is detectable in saliva for 2–3 days. The other components of Fioricet are far less detectable in saliva toxicology tests.

Fioricet detection in hair folicles

Butalbital deposits into hair follicles during use. Most drug tests are done on the top 2 cm of hair because Fioricet can be detected in hair for 90 days.

Factors that affect Fioricet elimination rate

There are many factors that can influence how long a drug takes to be processed by the body and eliminated. 

For instance, someone who has been using Fioricet for a long period of time or in high doses will carry the substance in their system for longer than someone who hasn’t. The same is also true if someone abuses multiple drugs or combines them with alcohol regularly. Using alcohol or MAOI antidepressants while taking Fioricet can be dangerous and may lead to overdose.

Other factors that influence Fioricet metabolization rates include:

  • Body fat

  • Height

  • Blood pressure

  • Gender

  • Age

  • Pre-existing medical conditions (especially those involving kidney or liver function)

Can you get a false-positive result for Fioricet?

False-positive results are extremely rare, occurring less than 1% of the time. However, Non-steroidal anti-inflammatory drugs (NSAIDs) such as naproxen and ibuprofen can trigger a false-positive result for butalbital.

If someone has tested positive for Fioricet in a toxicology report, their results may be sent for further testing in what is known as a gas chromatography-mass spectrometry (GC-MS) test. These tests are very rarely used as they are very sensitive, though they will rarely return a false-positive result.