My dad recently received an FDA Warning Letter, and we are a bit at a loss. This happened just a couple days ago, and it's not quite clear what to do next. I realize that this is a serious warning related to violating FDA regulations or standards, but don't know how to properly respond to it to avoid possible sanctions or follow-up inspections.

Should I immediately respond to the letter myself, or is it better to engage a professional for advice? If so, what kind of lawyer should we look for? Are there specialists who specifically deal with such issues, or will any lawyer related to medical or pharmaceutical law do? Also interested to know how best to prepare for further action, and what to expect from the FDA in dealing with this situation. If anyone has experienced something similar, any advice and guidance would be greatly appreciated.