Amoxicillin, Birth Control and Plan B

Patient: Dear Doctor, I am on the birth control pill orthotricyclen and i have also been taking amoxicillin for about eight days now. I had recently had sex and was wondering if becoming pregnant was a high chance of occuring. should I take plan B or would that alter anything for taking all three?

Doctor: Amoxicillin can interfere with the functioning of the oral contraceptive pill and decrease its effectiveness. I would ad vise alternative contraceptive measures like condoms when on amoxicillin. You may have to discuss with your doctor about the use of plan B.