But usually most penicillin, cephalosporins are thought to be safe, whereas macrolides, such as erythromycin,
azithromycin, are thought not to be. Also the antifungals are also not safe ( all the ones ending in azole). Besides antibiotics there are many other drugs which can also prologue the QT interval which you should be careful with.
Here is a reliable link:
http://www.azcert.org/medical-pros/drug-lists/bycategory.