How long does it take Butalbital (Fircocet) to kick in:
The pain-relieving effect of acetaminophen is reached within 30-60 minutes after ingestion. Butalbital is well absorbed from the gastrointestinal tract and produces muscle relaxant effects and sedation within one to two hours.
Butalbital is metabolized in the liver by the CYP450 enzyme system, which means it has a wide range of potential drug interactions. Because butalbital has a long half-life—an average of 35 hours—in the body, taking it repeatedly may have a cumulative effect that raises the risk of side effects.
Caffeine has a short half-life and is metabolized in the liver to other active substances (3 to 7 hours).
