How safe is hydroxyzine hcl. i was prescribed it for insomnia & anexity. i have been to afraid to start it though. i do have a history of low potassium & svt. should i be concerned?

In my experience cardiac stimulation would be a rare occurrence with hydroxyzine. It can be taken daily or as needed. Ensure that your serum potassium is in normal range at all times in view of your history of SVT. Avoid heavy caffeine & alcohol use. Your pharmacist may have more information about this matter or you could check with your cardiologist.