my 9yr. old shih Tzu has a heart murmur. she was coughing a lot, and dr. put her on Lasix, she also takes vetimed and potassium 2x daily. she has a good appetite, but won t eat her prescription food for cardiac problems. the last few days I haven t given her Lasix, because she s not coughing at all. she acts perky and hungry a lot. am I wromng for not giving her the Lasix all the time.?