Interactions – Which drugs cancels out the effectiveness of the pill?
Interactions can occur when taking two drugs. There are drugs that can influence the effectiveness of the minipill and can cancel the contraceptive protection. If a doctor prescribes a medicine, it is essential to point out that hormonal contraceptives must be taken.
The effect of the minipill can be affected by the following medications: antiepileptic drugs such as hydantoins, barbiturates, primidone, oxcarbazepine, topiramate, felbamate and other drugs used to treat epilepsy, drugs used to treat tuberculosis such as rifampicin. Other antibiotics can also influence the effectiveness of the pill, for example preparations which disturb the intestinal flora in patients. This is especially true for penicillin, tetracyclines, cephalosporins or cloramphenicol.
In addition to antibiotics, a large number of antivirals affect the effectiveness of the minipill, including ritanovir, rifabutin, efavirenz, nevirapin and nelfinavir. Griseofulvin, an antimycotic against fungal infections, is also one of the drugs of concern. The herbal medicine St. John’s wort, which is sometimes used for mild to moderate depression, also reduces the effectiveness of the pill via accelerated breakdown.
Activated carbon can also reduce the absorption of the active substance and thus the contraceptive protection. If it is necessary to take antibiotics, the prescribing doctor must be informed about hormonal contraception. He may make further recommendations.
In some cases the effectiveness of the pill is reduced by antibiotics, this is especially true of rifampicin in the treatment of tuberculosis. A variety of other antibiotics can also reduce the effectiveness of the minipill. By influencing the intestinal flora, the active ingredient of the minipill may not be fully absorbed and may not reach the necessary concentration in the blood to provide full contraceptive protection. The contraceptive protection may be impaired, especially in the case of vomiting or diarrhoea. Users should use additional barrier methods for safety reasons.
Intake during pregnancy and lactation
The minipill is the method of choice for breastfeeding mothers after non-hormonal contraceptive methods. Taking the minipill does not affect milk production. In addition, the proportion of the active ingredient that is transferred to the baby via breast milk is comparatively low.
So far there is no evidence that the growth or development of the breastfed child is impaired. If you are pregnant or suspect that you are pregnant, you should not take the minipill or stop taking it. If hormonal contraceptives are taken continuously during pregnancy, it cannot be completely ruled out that malformations may occur in the unborn child.
If you want to use contraception while breastfeeding, you should generally use non-hormonal methods. For women who still want to use hormonal contraception, the minipill is the method of choice when breastfeeding. In contrast to combination preparations, the preparation does not affect milk production.A small amount of the active ingredient reaches the infant through breast milk.
You should start taking the minipill no earlier than six weeks after delivery. To date, there is no evidence that taking the minipill in nursing mothers has any effect on the growth and development of the infant. Women who are breastfeeding should discuss the possibilities of contraception with their doctor.
