Pharmacological properties pharmacodynamics. Mifepristone is a synthetic steroidal antigestagenic agent (it blocks the action of progesterone at the receptor level), does not reveal progestogenic activity. There is antagonism with GCS (due to competition at the level of communication with receptors). Strengthens the contractility of the myometrium, stimulating the release of interleukin-8 in choriodecidual cells, increasing the sensitivity of the myometrium to prostaglandins. Depending on the phase of the menstrual cycle, it causes a delay in ovulation, changes in the endometrium and prevents the implantation of a fertilized egg. Pharmacokinetics. After a single dose of 600 mg Cmax in blood plasma of 1.98 mg / l is achieved after 1.3 hours. The absolute bioavailability is 69%. In blood plasma, mifepristone is 98% bound to proteins: albumin and acidic alpha-1 glycoprotein. After the distribution phase, excretion initially occurs slowly, the concentration decreases by 2 times between 12–72 hours, then much faster. T½ is 18 hours. Indications GYNEPRISTON immediate (postcoital) contraception (after unprotected intercourse or if the contraceptive method used cannot be considered reliable). The use of GINEPRISTON inside for 72 hours after unprotected intercourse by contraception, 1 tablet of Ginepristone 10 mg once. To maintain the effect of contraception, you should refrain from eating for 2 hours before and for 2 hours after using the drug. Ginepristone can be used during any phase of the menstrual cycle. Contraindications a history of hypersensitivity to mifepristone, adrenal insufficiency and long-term GCS therapy, acute or chronic renal and / or hepatic failure, porphyria, uterine fibroids, the presence of a scar on the uterus, anemia, hemostasis disorders (including previous treatment with anticoagulants), inflammatory diseases of the female genital organs, the presence of severe extragenital pathology. Severe BA. Side effects from the genitourinary system: spotting from the genital tract, menstrual irregularities, endometritis. From the nervous system: headache, dizziness. From the gastrointestinal tract: nausea, vomiting, diarrhea, abdominal cramps. On the part of the skin and subcutaneous tissue: urticaria, skin rashes. From the immune system: hypersensitivity reactions. Others: discomfort in the lower abdomen, weakness, malaise, chills, hyperthermia, toxic shock syndrome, breast tenderness.
Special instructions should be prescribed with caution in case of impaired hemostasis (including previous treatment with anticoagulants), chronic obstructive pulmonary diseases (including BA), severe hypertension, cardiac arrhythmias and heart failure, patients with a history of heart valve replacement, infective endocarditis ... Due to the anticorticosteroid activity of mifepristone, the effectiveness of long-term corticosteroid therapy, including inhaled corticosteroids in patients with asthma, may be reduced within 3-4 days after the use of mifepristone. In these cases, a dose adjustment of corticosteroids may be required. The drug is not recommended for regular use for the purpose of routine permanent contraception. The drug does not protect against sexually transmitted diseases and AIDS. The patient should be informed in advance about possible adverse reactions. If menstruation is delayed by more than 5 days or appears on time, but its course differs from normal, or for some reason there is a suspicion of pregnancy, the possibility of pregnancy must be excluded. Use during pregnancy and lactation. The drug should not be used during pregnancy. Breastfeeding should be stopped for 14 days after taking the drug. Children. Immediate contraception as a means of protection against unwanted pregnancy for adolescents is advisable to use only in emergency cases in persons who have been raped, taking into account all the possible consequences. The ability to influence the reaction rate when driving or operating machinery. There is no information on the effect of the drug on the ability to drive vehicles or work with complex mechanisms, but the possibility of developing adverse reactions from the nervous system (dizziness, weakness) should be taken into account.
Interactions should be avoided concomitant use with NSAIDs, it is not recommended to take NSAIDs in combination for 8-12 days after using the drug. Rifampicin, dexamethasone, some anticonvulsants (phenytoin, phenobarbital, carbamazepine) can stimulate the metabolism of mifepristone (reduce its concentration in blood plasma). Despite the fact that the metabolism of mifepristone occurs with the participation of the CYP 3A4 enzyme of the cytochrome P450 system, while taking the drug with inhibitors of this enzyme (ketoconazole, itraconazole, erythromycin, grapefruit juice), it is possible to inhibit the metabolism of mifepristone and increase its level in blood plasma. According to in vitro studies, the simultaneous use of mifepristone with drugs that are substrates of CYP 3A4 can lead to an increase in the level of these drugs in blood plasma. Due to the slow elimination of mifepristone from the body, this interaction can be observed for a long time after its use. Caution should be exercised when concomitant use of mifepristone with drugs that are substrates for CYP 3A4 have a narrow therapeutic range, including some drugs that are used during general anesthesia. Simultaneous use with NSAIDs should be avoided. Overdose of Ginepristone at a dose of up to 2 g does not cause adverse reactions. In case of an overdose of the drug, adrenal insufficiency is possible. Therapy is symptomatic. Storage conditions at a temperature not exceeding 30 ° С.
Tags: Emergency contraceptive.