Usually this is not a problem. If you are in doubt, or in case you are using non-standard veterinarian medicines, you can always contact us for advice.
It’s not recommended to feed macrolides (third choice of antibiotics in foals, not in grown up horses) simultaneously with COMFORT, IMMUNO or BASIC. This is because the mycotoxin binder will bind to the antibiotics which causes underdosing and possibly resistance.