Can you have a bad reaction from taking keflex while taking methadone?

Every antibiotic I have taken while on Methadone have had an effect on my Methadone. Most antibiotics have a small effect usually making the methadone less effective. Cipro specifically has an impact. The clinic where you get your methadone should have the drugs that effect strength your dose should be posted at the dispensing window. The dispensing nurse should be able to answer most simple questions and while most dispensing nurses act like they know everything but in reality in most states the are just LVN and unless they are very conscientious, their knowledge is not very extensive.