How long do you have to be off antibiotics for your birth control to be fully effective?

Few antibiotics affect Birth Control; examples inlude rifampin, griseofulvin, and a few HIV medications. For those antibiotics that do affect birth control, the length of time that the effect lasts depends on the mechanism of interference. Contact your health care provider for advice specific to your medication.

It's safest to take 7 active pills after your last antibiotic to ensure full effectiveness. If there aren't 7 active pills left in your pill pack before the placebos, the 7 pills starts the first week of the next pack.