I Have Had A UTI For 10 + Days And

I have had a UTI for 10 + days and used docycline 100mg bid for 5 days, it has not cleared, I had same problem about 4 weeks ago. Treated the same, I have a problem taking meds have reactions like rash, etc., had heart attack 10/6/2014. The culture this time says I need Rocephin shot to clear this up, is this drug dangerous?