Снова про КОК и антибиотики

[kitty_kitty]

Вот увидела соседнюю тему и заинтересовалась. Принимаю уже шесть месяцев Ясмин, очень нравится. Иногда бывают проблемы со здоровьем в виде цистита (острого, 3-5 дней нолицина убирают), к тому же (как и многие, к сожалению) страдаю (ну, пока не очень) периодон... тьфу, по-русски это пародонтит => принимаю антибиотики (макролиды). Беременностей не наступало ни разу.
Неужели ВСЕ антибиотики при комбинации с КОК требуют барьерной подстраховки? Я думала, только рифампицин, ну и пенициллин с амоксициллином...

[Dr.IrMa]

Читайте внимательно аннотации к препаратам. У каждого препарата могут быть свои особенности.

Если Вы не хотите получить беременность на фоне приема антибиотиков, чтобы потом решать, "вредно" это для будущего ребенка или "не вредно", лучше дополнительно предохраняться презервативом на время приема антибиотиков.
Не так ли?

[kitty_kitty]

Dr. IrMa,
спасибо за ответ, обязательно все читаю.
Если бы я хотела получить беременность, вряд ли бы принимала КОК
Я просто хотела узнать, а нет ли тут некой перестраховки. Витамин С, где-то читала, тоже снижает эффективность КОК.

[kitty_kitty]

Провела research, так скть.

Вот что нам говорит клиника Мэйо (май 2007):
Can antibiotics decrease the effectiveness of birth control pills?

The effects of antibiotics on birth control pills may be overstated — except in the case of one antibiotic, rifampin. Studies clearly show that rifampin decreases the effectiveness of birth control pills in preventing ovulation. However, rifampin isn't a widely used antibiotic. Chances are you wouldn't be taking it unless you had tuberculosis or had tested positive for the disease.

Hypothetically speaking, other antibiotics, particularly penicillin and tetracycline derivatives, could impair the effectiveness of birth control pills. However, no large studies have proved such an effect.

Researchers can't rule out the possibility that a small percentage of women may experience decreased effectiveness of birth control pills while taking an antibiotic. And if you're taking a newer, extremely low-dose oral contraceptive, you could be more susceptible to these potential effects from antibiotics. If you're concerned, consider using a barrier method of contraception for the duration of your antibiotic prescription.

Вот что говорит университет Пенсильвании:

With the exception of rifampin-like drugs, there is a lack of scientific evidence supporting the ability of commonly prescribed antibiotics, including all those routinely employed in outpatient dentistry, to either reduce blood levels and/or the effectiveness of oral contraceptives. To date, all clinical trials studying the effects of concomitant antibiotic therapy (with the exception of rifampin and rifabutin) have failed to demonstrate an interaction. Like all drugs, oral contraceptives are not 100% effective with the failure rate in the typical United States population reported to be as high as 3%. It is thus possible that the case reports of unintended pregnancies during antibiotic therapy may simply represent the normal failure rate of these drugs. Considering that both drug classes are prescribed frequently to women of childbearing potential, one would expect a much higher rate of oral contraceptive failure in this group of patients if a true drug:drug interaction existed.

А Нидерланды сообщают:

CONCLUSION: The results from these studies demonstrate the absence of pharmacokinetic interactions between etonogestrel and ethinylestradiol released from NuvaRing and the oral antibiotics amoxicillin and doxycycline, suggesting that contraceptive efficacy would also be unaffected.

Вот...

[Dr.IrMa]

Читайте Speroff. Классика. Там все-все написано.

[kitty_kitty]

Так читаю же:
There are many anecdotal reports of patients who conceived on oral contraceptives while taking antibiotics. There is little evidence, however, that antibiotics such as ampicillin, metronidazole, quinolone, and tetracycline, which reduce the bacterial flora of the gastrointestinal tract, affect oral contraceptive efficacy. Studies indicate that while antibiotics can alter the excretion of contraceptive steroids, plasma levels are unchanged, and there is no evidence of ovulation.299, 300 A review of a large number of patients derived from dermatology practices failed to find an increased rate of pregnancy in women on oral contraceptives and being treated with antibiotics (tetracyclines, penicillins, cephalosporins).301

[Dr. Nika]

Kitty

ЕВМ имеет конкретный ответ на ваш впрос:
[Ссылки доступны только зарегистрированным пользователям ]

FFPRHC CEU guidance advises that it has been practice in the UK to advise additional contraceptive protection forwomen using combined hormonal contraception when broad-spectrum antibiotics are used.

When taking a short course (<3 weeks) of any non-liver enzyme inducing antibiotic additional contraceptive protection, such as condoms, is advised during the treatment and for 7 days after the antibiotic is stopped.
If fewer than seven pills are left in the packet after antibiotics have stopped she should to omit the pill free interval or discard any inactive pills.
When any non-liver enzyme-inducing antibiotic is taken for ≥3 weeks additional contraceptive protection is no longer required. If a new antibiotic is prescribed however, advice is as for short courses.
New COC user:
When starting a COC if currently taking a short course (<3 weeks) of any non-liver enzyme inducing antibiotic additional contraceptive protection, such as condoms, is advised during the treatment and for 7 days after the antibiotic is stopped.
When starting a COC if any non-liver enzyme-inducing antibiotic has been taken for ≥3 weeks additional contraceptive protection is not required.


Прошу прощения у модераторов, что привожу цитату на английском, но из сообщений автора поста следует, что автор английский понимает:-)

[kitty_kitty]

Dr. Nika,
спасибо большое за связные рекомендации. Мне похожее пришлось вылавливать по дюжине источников раздельно
Только все равно этот подход, хотя теоретически и понятен, на практике, как мне подсказывает литература (и сам этот документ), shows little evidence... if any

Вы простите за назойливость, мне хочется понять

Зы. Зачиталась Speroff'ом. "...the estrogenic component significantly contributes to the contraceptive efficacy. However, even if follicular growth and development were not sufficiently inhibited, the progestational component would prevent the surge-like release of LH necessary for ovulation".
И в ссылке Dr.Nika: "Antibiotics do not affect progestogens, as metabolites are inactive."
Получается, что прогестиновый компонент все равно подстрахует на случай гипотетической утраты эстрогенового? Ну как мини-пили? По Speroff'у 0,5% попаданий вместо 0,1%... Получается или не получается?

[Dr. Nika]

Получается, что пока придерживаемся ЕВМ, как и во многих случаях, когда практика и теория показывает некую статистику, но данных этих недостаточно, чтобы их внесли в рекомендации ЕВМ :-)
Ждем обновления:-) Уверена, что не только Вы озадачились этой цепочкой заключений и что новые рекомендации не за горами:-)

[kitty_kitty]

Спасибо, Dr. Nika, и осторожно, и логично.

А для тех, кто еще озадачился:
(UpToDate 15.1)
Antibiotics — Rifampin may be among the most potent agents in decreasing oral contraceptive efficacy [17]. Other antibiotics do not affect the pharmacokinetics of ethinyl estradiol [26,27]. However, individual women have had been reported to have significant decreases in the plasma concentrations of ethinyl estradiol when taking certain other antibiotics, such as tetracycline, penicillin derivatives, and cephalosporins [26,28]. Because it is not possible to identify these women in advance, a cautious approach has been advised. The Council on Scientific Affairs of the American Medical Association recommends that women be informed of this small risk. Women who are either uncomfortable with this risk or who have had previous breakthrough bleeding or contraceptive failure during concomitant use of antibiotics, should be counseled about additional use of nonhormonal contraceptive methods [28].

UPD: не полностью скопировала

Recommendation — A nonhormonal contraceptive method is recommended for women taking rifampin or anticonvulsants, while hormonal methods are reasonable for women on griseofulvin [19,29]. Back-up contraception is advised for those receiving tetracyclines, penicillins, or cephalosporins. Women using both St. John's wort and OCs should be cautioned about possible reduced contraceptive efficacy.