How long is inpatient treatment for a painkiller addiction?

Inpatient care for opiate dependency is variable, depending on drug, dosage, duration of use, route of administration and a number of other factors.  I have had patients with the same issue you bring up:  the employer finding out, and I have seen some patients sneak in a detox while telling the employer that they are on vacation.  My opinion is that when you reach a point where you are going to need inpatient treatment, that this is primary and worry about what your employer - or anyone - might say.  My suggestion is that you find the best possible treatment program, get yourself healthy and worry about your employer later.  If you don't deal with your drug problem, it is going to end up ruining your career anyway.