I am currently on birth control and have been for years. I never miss a pill and it is not time for my period. I have been using nifedipine cream for 11 days now and have "break through bleeding". Can this happen from the ointment?? It never happens any other time!! And does anyone know if it decreases the effectiveness of the pill?? Help!!

Hi!
Yes, we've had a few women (including myself) who have had increased menstrual bleeding with nifedipine.
As far as interaction with oral contraceptive effectiveness, I really don't know for sure so your safest bet is to ask both your doctor AND your pharmacist because that is a really really important question for your family planning.