Can antibiotics affect IUDs like Kyleena, Mirena, or Skyla?
No, antibiotics do not affect IUDs such as Kyleena, Mirena, or Skyla. In fact, there are not many contraceptive devices or even contraceptives that are affected by antibiotics, despite popular belief that this is the case.
There are only two situations where antibiotics can affect ORAL contraceptives (not IUDs, injectable or implantable contraceptives). These are:
- If the antibiotic or the bacterial condition being treated with the antibiotic causes diarrhea or vomiting. This may reduce the time the oral contraceptive has to be absorbed, which may lower levels of contraceptive hormones in the body, increasing the risk of pregnancy
- If the antibiotic being given is either rifampin or rifabutin, and it is being given for 2 months or longer. Both these antibiotics induce (speed-up) the metabolism of liver enzymes, which can lower the blood levels of oral hormonal contraceptives.
Hormone-releasing IUDs such as Kyleena, Mirena, or Skyla work directly in the uterine cavity and do not rely on absorption through the stomach or metabolism through the liver for their effect, making drug interactions far less likely.
Why do people think that antibiotics affect contraceptives?
Research has shown that with combined oral contraceptives, the estrogen component (usually ethinyl estradiol) undergoes enterohepatic recirculation. This means that it is absorbed through the stomach wall and then metabolized in the liver to form inactive conjugates with glucuronide, which are then excreted back into the duodenum in the bile. Bacteria within our stomach and intestine then cleave (break apart) these conjugates, and the active estrogen is then reabsorbed and can exert its effects.
Researchers also had a theory that if these bacteria were suppressed or killed (which happens if you take a broad-spectrum antibiotic) then this would prevent these conjugates from being cleaved, which could result in lower than normal concentrations of estrogen which might cause contraceptive failure, increasing the risk of pregnancy.
However, subsequent research has shown two things. Firstly, the enterohepatic recirculation of estrogen is not important and large studies investigating women taking oral contraceptives in conjunction with non-enzyme inducing antibiotics have not shown any decreased levels of ethinyl estradiol nor an increased incidence of pregnancy. If diarrhea or vomiting does occur, then a woman should be advised to follow the “seven-day rule”, which means using other methods of contraception (eg, condoms or abstinence) until seven active pills have been taken and the diarrhea has ceased.
Secondly, that the only antibiotics that could affect oral hormonal contraceptives are those that induce enzymes, and currently, there are only two of these available, rifampin and rifabutin which are used to treat tuberculosis and meningitis. Women who take either rifampin or rifabutin for more than two months are advised to change from their oral contraceptive to another method (such as an implant or IUD) that is not affected by these medications.
Related questions
- What should I expect after a Mirena IUD removal?
- What are the side effects of IUDs?
- Can you get pregnant with an IUD?
How do hormone-releasing IUDs work?
Kyleena, Mirena, and Skyla work by releasing a continuous, low-dose of levonorgestrel (a progesterone hormone) which is thought to prevent pregnancy by thickening cervical mucus which prevents the passage of sperm into the uterus, inhibiting the motility of sperm and their survival, and changing the endometrium so it is unable to accommodate a fertilized egg.
What are the differences between Kyleena, Mirena, and Skyla?
Kyleena, Mirena, and Skyla are all T-shaped contraceptive devices that slowly release levonorgestrel and are placed inside a woman’s uterus to prevent pregnancy. The main differences between them are how long they last for, how much levonorgestrel they release, and the size of the device.
For more information about the differences between Kyleena, Mirena, and Skyla, see here.
References
- Will antibiotics stop my contraception working? NHS https://www.nhs.uk/conditions/contraception/antibiotics-contraception/
- Reminder: Most broad-spectrum antibiotics do not interact with combined oral contraceptives BPAC BPJ Issue 61. https://bpac.org.nz/BPJ/2014/june/docs/BPJ61-news.pdf
- Simmons KB, Haddad LB, Nanda K, Curtis KM. Drug interactions between non-rifamycin antibiotics and hormonal contraception: a systematic review. Am J Obstet Gynecol. 2018 Jan;218(1):88-97.e14. DOI: 10.1016/j.ajog.2017.07.003. Epub 2017 Jul 8. PMID: 28694152.
Read next
Can Kyleena cause weight gain?
Yes, Kyleena can cause weight gain in some women although this is not listed as a common side effect of Kyleena. Weight gain associated with Kyleena is most likely due to water retention caused by the progestin contained in Kyleena, rather than an increase in body fat percentage. In most women, the bloating should subside within a few months. Continue reading
Can Kyleena cause acne?
Yes, acne is a common side effect of Kyleena, reported in 14.1% of women who were assigned to Kyleena in clinical trials. Women who are predisposed to hormonal acne (for example, they typically have a breakout of acne just before their period) are more likely than others to develop acne with Kyleena. Continue reading
Can Kyleena make your period stop?
Yes, Kyleena may make your period stop. Research has shown that 12 out of 100 women (12%) or women stop having periods after one year of Kyleena use. Typically, most women experience some sort of change in their periods, usually during the first three to six months after Kyleena insertion. Their periods may become lighter or more irregular or spotting may occur in between periods. Some women experience heavy bleeding during this time. However, these changes usually settle down after about 6 months with most women experiencing shorter and lighter periods once their body adjusts. Continue reading
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