For the same, you can decrease the dose of
coreg to 3.125 mg twice a day instead of giving it 6.25 mg once a day as it has got a short
half life and stops acting after 12 hrs. The other option is to decrease the dose of lasix to 20 mg daily.
Please make sure that she’s not taking any extra salt apart from the salt in her food like any salt on the salad, in the curd etc.
However, a decrease in BP could be a manifestation of the worsening of the function of the heart.
I hope that helps.