Im currently taking Microgynon 30, and was prescribed Amoxicillin 500mg as I m having sinus problems, i have been taking the antibiotics for 4 days now. I wasn t informed on whether these antibiotics would affect my pill, and have been sexually active since taking the antibiotics without taking extra precautions. Does Amoxicillin havean effect on my pill? What do you advise I do? I will go for a morning after pill tomorrow, i started taking the Amoxicillin on Friday at 1pm, and wAs sexually active on Saturday at around 1am, I haven t been since then onwards.