Jetcareers.com has an AME that works their "Ask an AME" forum. He's available by email as well. AOPA has the same on their forums, if you're a member.

My AME advised me that the typical time period for the first level narcotics has been 72 hours, or about 3x the half-life. These are the Codeines, Vicodens, Percosets, and so on. Step into MS Contin, morphine, dilaudid, and others of this class, and my AME advised at least a week off of the meds, plus depending on the underlying condition and/or cause, call before attempting to fly for consideration of other probs like concussion, TBI, and so on from a car accident.

I am not a doc nor an AME, and don't play one on the internet.