Hi Greatmuffin,
As we are not medical professionals here it would be best to have your question answered by a doctor, as any time medications are mixed complications may arise. I don't have experience in taking either of these drugs, although I know that some antibiotics may decrease the effectiveness of contraceptives. In doing some research I came accross a University of Oregon website (http://studenthealth.oregonstate.edu/answerspot/message.php?message=6540), on which the same question was posted:
"Question: My doctor just put me on Cipro for a UTI. I am also on the pill (Ovcon 35). Can the Cipro cause the pill to be less effective?
Answer: When a woman is taking oral contraceptives and has to also take antibiotics (such as Cipro) that could decrease the effectiveness of the oral contraceptives, it is recommended that she use a back up method of contraception (i.e. a condom) during the entire time she is on the antibiotics and for 7 days after she stops taking the antibiotics. For more information, you may want to consult with a health care provider or a pharmacist."
I would still advise you to check with your doctor. Everyone responds differently to drugs and your doctor will be the best person to consult in this case.
Good luck!
i agree with JW in that you really should be checking with your doctor, or better yet...call your pharmacy & ask the pharmacist. They are the experts when it comes to drug interactions.