Is esgic (acetaminophen butalbital and caffeine) an effective pain reliever other than for headaches?

Yes: Esgic, (acetaminophen butalbital and caffeine) also known by the name Fioricet contains butalbital (a barbiturate), caffeine and acetaminophen. It can help for pain other then headache. You have to be very cautious with barbiturates however. They can cause significant CNS depression. And if used too often can cause rebound headaches. It would be safer to use Acetaminophen or an NSAID alone.