My Son Is 1 Year Old. He Has Been Passing

My son is 1 year old. He has been passing loose stool for two days , 3-4 times a day. Today his stools are more watery. I have mistakenly given him 2.5 ml ofloxin Oz then I read in Google that it is not recommended in kids. We have consulted a doctor has has prescribed zifi 50 mg that also an antibiotics. Can I start it from tomorrow as I have given oflox Oz today. Does it have any adverse effect. Kindly suggest.