Patient: I am currently on the combined pill. Me and my boyfriend have regular sex. However I have just been prescribed with amoxicillin as I have tonsillitis . I am taking these through the week I am meant to have a withdrawal bleed. I have heard that sperm lasts for seven days (we have had sex within these seven days) And as these antibiotics stop the pill from working could this mean I may be pregnant? PLEASE HELP!
Doctor: The effectiveness of active oral contraceptives may be impaired by concomitant treatment with antibiotics. However, anti biotics may not affect the placebo or the non active pills, meant to be taken during the week of withdrawal bleeding. Although sperms have a lifespan up to 3-5 days following deposition, your active pills have been maximally effective this cycle and so will be through the next cycle, since you finished your antibiotics through the placebo week (preventing any effects on the active pills). Thus it is unlikely that you may be pregnant. It is always safe to use an additional method of contraception while on antibiotics.