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Z pack and Birth control
An_249596 posted:
I was taking a 5 day prescription z pack for an upper respriority infection and I am also on an ortho tri cyclen birth control pill. Well on the 5th day of my z pack I had unprotected sex with my boyfriend not thinking anything of it because I was doing so well on taking my pill regularly. I totally forgot about the antibiotics interfering with the effects of my pill and now I am very very worried about being pregnant. Can anyone please help me out and give me some information! Thank you!
tlkittycat1968 responded:
There are actually very few antibiotices tha affect birth control tand those that do are usually prescribed for TB. You did not have unprotected sex as you were on the pill.
MrsLiyahPooh responded:
im in the same situation. did you ever become pregnant?
Jane Harrison Hohner, RN, RNP replied to MrsLiyahPooh's response:
Dear MrsLiyahPooh & An: tlkittycat has spoken correctly. Here are some additional medications which are known to decrease effectiveness of birth control pills (BCPs):

? Alertness drugs (eg Nuvigil) can enhance rapid metabolism of estradiol by increasing liver enzyme activity thus decreasing hormone levels.
? Barbiturates (eg, phenobarbital), hydantoins (eg, phenytoin), carbamazepine, rifampin, or St. John's wort because they may decrease estradiol effectiveness.

In terms of other, common antibiotics interactions with BCPs:
? Azole antifungals (eg, ketoconazole) or macrolide antibiotics (eg, erythromycin, azythromycin, Biaxin) may increase the risk of estradiol 's side effects by increased blood levels of estradiol. Thus these would actually increase effectiveness of BCPs.


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