I’ve been on both Cipro and Flagyl for years, and they have neither improved nor worsened my driving. Sometimes side effects can occur (e.g. dizziness, confusion, disorientation, etc.) that would make driving a poor idea, but as long as you’re paying attention you’ll notice that something isn’t right, and that driving would be ill-advised.
Flagyl can interact badly with alcohol, but that’s not broadly true of most antibiotics.