Oligest Drug Interactions

Effects of Other Medicinal Products on Dienogest: Progestogens including dienogest are metabolized mainly by the cytochrome P450 CYP3A4 located both in the intestinal mucosa and in the liver. Therefore, inducers or inhibitors of CYP3A4 may affect the progestogen drug metabolism. An increased clearance of sex hormones due to enzyme induction may reduce the therapeutic effect of dienogest and may result in undesirable effects e.g. changes in the uterine bleeding profile.
A reduced clearance of sex hormones due to enzyme inhibition may increase the exposure to dienogest and may result in undesirable effects.
Substances increasing the clearance of sex hormones (diminished efficacy by enzyme-induction), e.g.: phenytoin, barbiturates, primidone, carbamazepine, rifampicin, and possibly also oxcarbazepine, topiramate, felbamate, griseofulvin, and products containing St. John's wort.
Enzyme induction can already be observed after a few days of treatment. Maximum enzyme induction is generally seen within a few weeks. After cessation of drug therapy, enzyme induction may be sustained for about 4 weeks.
The effect of the CYP3A4 inducer rifampicin was studied in healthy postmenopausal women. Coadministration of rifampicin with estradiol valerate/dienogest tablets led to significant decreases in steady state concentrations and systemic exposures of dienogest.
Substances with variable effects on the clearance of sex hormones, e.g.: When co-administered with sex hormones, many combinations of HIV/HCV protease inhibitors and nonnucleoside reverse transcriptase inhibitors can increase or decrease plasma concentrations of the progestin. The net effect of these changes may be clinically relevant in some cases.
Substances decreasing the clearance of sex hormones (enzyme inhibitors) dienogest is a substrate of cytochrome P450 (CYP) 3A4.
Concomitant administration of strong CYP3A4 inhibitors can increase plasma concentrations of dienogest.
Coadministration with the strong CYP3A4 enzyme inhibitor ketoconazole resulted in a 2.9-fold increase of AUC (0-24h) at steady state for dienogest. Concomitant administration of the moderate inhibitor erythromycin increased the AUC (0-24h) of dienogest at steady state by 1.6-fold.
Effects of Dienogest on Other Medicinal Products: Based on in vitro inhibition studies, a clinically relevant interaction of dienogest with the cytochrome P450 enzyme mediated metabolism of other medication is unlikely.
Interaction with Food: A standardized high fat meal did not affect the bioavailability of dienogest.
Laboratory Tests: The use of progestogens may influence the results of certain laboratory tests, including biochemical parameters of liver, thyroid, adrenal and renal function, plasma levels of (carrier) proteins (e.g. corticosteroid binding globulin and lipid/lipoprotein fractions), parameters of carbohydrate metabolism and parameters of coagulation and fibrinolysis. Changes generally remain within the normal laboratory range.