Minulet Drug Interactions

Interactions between ethinyl estradiol (EE) and other substances may lead to decreased or increased serum EE concentrations, respectively.
Concomitant use with the medicinal products containing ombitasvir/paritaprevir/ritonavir and dasabuvir, with or without ribavirin may increase the risk of ALT elevations (see Contraindications and Special Warnings: Hepatic neoplasia/liver disease/hepatitis C under Precautions). Therefore, users must switch to an alternative method of contraception (e.g., progestogen-only contraception or non-hormonal methods) prior to starting therapy with this combination drug regimen. MINULET can be restarted 2 weeks following completion of treatment with this combination drug regimen.
Decreased EE serum concentrations may cause an increased incidence of breakthrough bleeding and menstrual irregularities and may possibly reduce efficacy of the COC.
During concomitant use of EE-containing products and substances that may lead to decreased EE serum concentrations, it is recommended that a nonhormonal back-up method of birth control (such as condoms and spermicide) be used in addition to the regular intake of MINULET.
In the case of prolonged use of such substances COCs should not be considered the primary contraceptive.
After discontinuation of substances that may lead to deceased EE serum concentrations, use of a nonhormonal back-up method is recommended for at least 7 days. Longer use of a back-up method is advisable after discontinuation of substances that have led to induction of hepatic microsomal enzymes, resulting in decreased EE serum concentrations. It may sometimes take several weeks until enzyme induction has completely subsided, depending on dosage, duration of use and rate of elimination of the inducing substance.
Examples of substances that may decrease serum EE concentrations: Any substance that reduces gastrointestinal transit time and, therefore, EE absorption.
Substances that induce hepatic microsomal enzymes, such as rifampicin, rifabutin, barbiturates, primidone, phenylbutazone, phenytoin, dexamethasone, griseofulvin, topiramate, some protease inhibitors, modafinil.
Hypericum perforatum, also known as St. John's wort, and ritonavir* (possibly by induction of hepatic microsomal enzymes).
*Although ritonavir is an inhibitor of cytochrome P450 3A4, treatment with ritonavir has been shown to decrease EE serum concentrations (see previously mentioned).
Examples of substances that may increase serum EE concentrations: Atorvastatin.
Competitive inhibitors for sulfation in the gastrointestinal wall, such as ascorbic acid (vitamin C) and paracetamol (acetaminophen).
Substances that inhibit cytochrome P450 3A4 isoenzymes such as indinavir, fluconazole, and troleandomycin*. Troleandomycin may increase the risk of intrahepatic cholestasis during coadministration with COCs.
EE may interfere with the metabolism of other drugs by inhibiting hepatic microsomal enzymes, or by inducing hepatic drug conjugation, particularly glucuronidation. Accordingly, plasma and tissue concentrations may either be increased (e.g., cyclosporine, theophylline, corticosteroids) or decreased (e.g., lamotrigine).
In patients treated with flunarizine, use of oral contraceptives has been reported to increase the risk of galactorrhea. There have been reports of pregnancy when COCs were co-administered with certain antibiotics (e.g., ampicillin and other penicillins, tetracyclines).
The prescribing information of concomitant medications should be consulted to identify potential interactions.
Laboratory test information: Estrogen-containing preparations can affect many laboratory tests. Some examples are: Increased prothrombin and Factors VII, VIII, IX, and X; decreased antithrombin 3; increased norepinephrine-induced platelet aggregability.
Increased thyroid-binding globulin (TBG) leading to increased circulating total-thyroid hormone, as measured by protein-bound iodine (PBI). T4 by radioimmunoassay. Free T3 resin uptake is decreased, reflecting the elevated TBG; free T4 concentration is unaltered.
Reduced response to metyrapone test.
The results of these tests should not be regarded as reliable until oral contraceptive use has been discontinued for 1-2 months. Abnormal tests should then be repeated.
Oral contraceptives may produce false positive results when neutrophil alkaline phosphatase activity is evaluated for the early diagnosis of pregnancy.