L.M.
I have had at least one (often more) round of bronchitis every year since I was a very young child. No only should you drink that 8oz of water, you should drink as much liquids as possible. The more hydrated you are, the more it loosens congestion. If you can't take anything else but don't want to take this because of the possible side effects (I am not familiar with this drug) you should talk to your doctor about alternatives...you do need an antibotic to get better though.
Regardless of the medication and liquids be sure to get lots of rest.