RM Anova or Ancova

I have two groups of people (one young one older) each receiving the same blood pressure medication daily, with blood pressure measured daily for 14 days. There is a fairly large difference in blood pressure at baseline (20 mmHg higher in the older group). Blood pressure decreased in both groups, but I would like to find if the response between the two groups is different. Would it be best to run a rm ANCOVA with post hoc multiple comparisons at each timepoint (baseline difference as the covariate)? Or rm anova with post hoc tests?
Also would there be a disadvantage to using baseline subtracted data and simply running a rm anova with post hoc tests at each time point?