My girlfriend is on the birth control Implanon, she's had


Q: My girlfriend is on the birth control Implanon, she's had it for over 3 years and just got her re-insertion over a month ago. We started using condoms a week before her 1st implant expired and have used them ever since she got the re-insertion just to be extra safe. We were going to start having sex without condoms again, but she had to go to the dentist for a bad toothache yesterday and was prescribed amoxicillin. She was told by her pharmacist that antibiotics can affect hormonal birth control and to use another method if she was on hormonal birth control.

I looked into this and have found some mixed answers on this. It is stated that many doctors just think of it in very broad, vague terms - antibiotic + hormonal contraceptive = bad .. but I have found other results that it is not that simple. I've read on medical sites that it is only certain antibiotics that have a negative effect, and amoxicillin isn't one of them. In addition, I've read that it is only certain specific types of birth control that are effected in a negative way, and Implanon is not one of these.

I would just like a CLEAR & CONFIDENT answer on the interaction between these two medications. I know most of the answers will be "just use condoms to be safe regardless of the interaction" but I would like to know the actual answer to this question. Thanks!


A:   Hello,
Thanks for the query to ATD.

I appreciate and applaud your concern for yes, i agree that most gynecologists would advise to use alternative methods of contraception with antibiotic use , but it is not valid for an implant which is purely a progesterone contraceptive device. The thought is valid for oral contraceptives with oestradiol which undergoes enterohepatic circulation and the antibiotics like amoxycillin blocks this pathway and hence render it ineffective, but no in case of progesterones.
The progestins present in oral contraceptive pills (eg, levonorgestrel, norethisterone, desogestrel, gestodene, norgestimate) also undergo conjugation. Hydrolysis of conjugates leads to the formation of inactive metabolites because the parent molecule cannot be directly conjugated. Progestins are not thought to undergo extensive enterohepatic cycling and are, thus, less likely to be involved in drug interactions with antibiotics than ethinylestradiol.
So with the above reason, amoxicillin dose for 5 days would not render it ineffective.
I hope I have answered your query in detail,

Wishing you good health,

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