Moggies with high blood pressure

Hi I am new to site. My Cat Molly is 14 and just gone blind -she had High blood pressure(240) so was put on BP tablets but after 3 days we thought she was dying as wouldnt eat or drink or move.We were ready ro have her put to sleep. Stopped tablets this weekend and she has perked up and is eating- Vet says shouldnt have this effect but seems coincidence- has anyone else had this happen?