Estelle-35 Drug Interactions

Effects of other medicaments on Estelle-35: Interactions can occur with drugs that induce microsomal enzymes which can result in increased clearance of sex hormones and which may lead to breakthrough bleeding and/or contraceptive failure.
There have been reports of pregnancy while taking hormonal contraceptives and antibiotics, but clinical studies in women demonstrate no evidence of an interaction between COCs and non-enzyme inducing antibiotics. Rifampicin and griseofulvin are two enzyme-inducing antimicrobials that are known to reduce the efficacy of COC.
Women on treatment with any of these drugs should temporarily use a barrier method in addition to Estelle-35 or choose another method of contraception. The barrier method should be used during the time of concomitant drug administration and for 28 days after their discontinuation. If the period during which the barrier method is used runs beyond the end of the tablets in the Estelle-35 pack, the next pack should be started without the usual tablet-free interval.
Substances increasing the clearance of Estelle-35 (diminished efficacy of Estelle-35 by enzyme-induction), e.g.: phenytoin, barbiturates, primidone, carbamazepine, rifampicin, and possibly also oxcarbazepine, topiramate, felbamate, griseofulvin and products containing St. John's wort.
Substances with variable effects on the clearance of Estelle-35, e.g.: When co-administered with Estelle-35, many HIV/HCV protease inhibitors and non-nucleoside reverse transcriptase inhibitors can increase or decrease plasma concentrations of estrogen or progestin. These changes may be clinically relevant in some cases.
Effects of estrogen/progestogen combinations on other medicaments: Estrogen/progestogen combinations like Estelle-35 may affect the metabolism of certain other drugs. Accordingly, plasma and tissue concentrations may either increase (e.g. cyclosporins) or decrease (e.g. lamotrigine).
Other forms of interactions: Laboratory tests: The use of preparations like Estelle-35 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.
Note: The prescribing information of concomitant medications should be consulted to identify potential interactions.