Q2:
A. She did not actually swallow the medication when it was given since she did not like the taste.

Metronidazole tastes terrible, and the taste lingers after it is absorbed since the drug is also secreted with saliva and other bodily fluids. If she was not observed taking the medication, it is possible that took some, but not all of the pills and failed treatment. The argument against this is that she reports having become nauseated, which suggests that she took enough of the metronidazole to experience this common side effect.

With many “single-dose” treatments for STDs, it is often a good idea to have the patient take the medication in the presence of a nurse or doctor and have them wait to make sure that the medication is retained.