Hi.. Well it is not always necessary that Azithromycin can cause heart attack as it can occur in a very few rare cases or in certain mwdically compromised patients.. So if Amoxicillin is not working you can take Azithromycin or Amoxicillin with Clavulanate potassium so that it becomes more effective.. Along with it you can take cough suppressant like Dextromethorphan and along with it do steam inhalation. If fever persist ypu can take Aceta. Do sufficient rest and take light meals.. Hope I have answered your query. Please let me know if I can assist you further.. Regards. Dr. Honey Arora, Dentist.