Interactions between estrogen/progestagen combinations like Diane-35 and other drugs may lead to breakthrough bleeding and/or contraceptive failure.
Various substances, such as barbiturates, rifampicin and antiepileptic drugs (such as barbexaclone, carbamazepine, phenytoin, primidone) and possibly also oxcarbazepine, topiramate, felbamate, griseofulvin and products containing St. John's wort (Hypericum), accelerate the metabolisation of sex hormones (possible loss of contraceptive effect).
Also HIV protease inhibitors (e.g. ritonavir) and non-nucleoside reverse transcriptase inhibitors (e.g. nevirapine), and combinations of them, have been reported to potentially affect hepatic metabolism.
Diane-35 may affect the metabolism of certain other drugs. Accordingly, plasma and tissue concentrations may either increase (e.g. cyclosporin) or decrease (e.g. lamotrigine).
Women who are being treated with a medication of the substance classes mentioned above should use additional barrier contraceptives alongside the combination oral contraceptive, i.e. while taking the concomitant medication and for 28 days afterward.
Reduced levels of the active ingredients have been observed due to alteration of the intestinal flora when some antibiotics (e.g. penicillins and tetracyclines) are taken at the same time. Increased rates of intermenstrual bleeding as well as isolated pregnancies have been recorded. Women receiving antibiotic treatment should use additional barrier contraceptives during this time of concomitant medication and for 7 days afterward. If the use of an additional barrier contraceptive overruns the end of the pack, the next Diane-35 pack should be started without a 7-day break.
The requirement for antidiabetics can change as a result of the effect on glucose tolerance.
Note: Diane-35 may not be used with an additional hormonal contraceptive; such medicinal products have to be discontinued prior to starting treatment with Diane-35 (for this, see also Dosage & Administration).