Starting buprenorphine too early can trigger precipitated withdrawal, a sudden and severe reaction rather than the gradual withdrawal someone would otherwise expect. This is one reason inducting onto buprenorphine is timed carefully around a person's last use.
Some herbal supplements, like St. John's Wort, are strong inducers of the liver enzyme CYP3A4, which can lower blood levels of methadone or buprenorphine and reduce how well they work — a fact rarely mentioned outside clinical literature.
If your insurance denies coverage for medication treatment, federal and state parity laws may require your plan to cover it the same way it covers other medical conditions — this is a real legal basis for an appeal, not just a talking point.