Diarrhea and vomiting affect the action of oral contraceptives.

Question: Diarrhea and vomiting affect the action of oral contraceptives. Is it true or not?

Answer: The data found that diarrhea and vomiting affect the action of oral contraceptives. The diarrhea that results in reduced effectiveness of oral contraceptives is severe diarrhea. It does not have to define definition of severe diarrhea (such as yet undefined number of time that defecation), and there is no evidence or clinical studies about the efficacy of the drug to decline that would affect pregnancy or hormone levels when severe diarrhea.

There is also a suggestion that if the diarrhea for at least 48 hours during taking oral contraceptives. It is not necessary to eat more contraceptives and do not need to use another more contraception.

But if you have diarrhea for up to 48 hours or longer, it is recommended to eat the next tablet of contraceptives as usual, but using drug together with other methods of contraception, such as using condoms, or avoiding having sex as long as until having eaten a pill every day for at least seven days after stopped diarrhea. And it may require more emergency contraceptives in some cases that have sex without protection.

Reference:

1. US Selected Practice Recommendations for Contraceptive Use, 2013. MMWR 2013; 62 (5): 1-60.