Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
When these two medicines are taken together, the antibiotic medicine may alter the way your body processes the birth control pill.
What might happen:
The effect of your birth control pills may decrease and cause breakthrough bleeding, spotting, or even unintended pregnancy.
What you should do about this interaction:
Contact your healthcare professionals (e.g. doctor or pharmacist) as soon as possible about using an additional form of birth control during, as well as continuing for a few days after completing antibiotic treatment.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.Reference:1.Marvelon (desogestrel-ethinyl estradiol) Canadian prescribing information. Organon 2008.