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CONTENT: Fempro, 2.5mg (10 pills)
Antineoplastic agent, an inhibitor of the synthesis of estrogens. Letrozole has an antiestrogenic effect, selectively inhibits aromatase (an enzyme for the synthesis of estrogens) through highly competitive binding to the subunit of this enzyme, the heme cytochrome P450. It blocks the synthesis of estrogens in both peripheral and tumor tissues.
In postmenopausal women, estrogens are mainly produced with the involvement of the aromatase enzyme, which converts the androgens synthesized in the adrenal glands (primarily androstenedione and testosterone) into oestrones and oestradiol.
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The drug is taken orally, regardless of food intake.
The recommended dose of letrozole is 2.5 mg once / day, daily, long (for 5 years or until relapse).
As an extended adjuvant therapy, treatment should last for 4 years (no longer than 5 years).
If signs of disease progression appear, letrozole use should be discontinued.
In patients with recent illness or a metastatic tumor, treatment with letrozole should be continued until the tumor progresses.
Correction of the letrozole dose is not required in elderly patients.
Side effects
Letrozole, as a preparation for adjuvant therapy for breast cancer, as well as an agent for the treatment of early stages of breast cancer (in people previously treated with tamoxifen), is well tolerated by patients.
Side effects on the background of treatment with letrozole in most cases were due to the lack of estrogens that the drug caused.
Side effects are presented based on data from clinical trials and post-control licenses.
Adverse effects of:
Blutsysteme: Leukopenie;
Urinary tract: urinary tract infection, frequent urination;
Nervous system: Anxiety, irritability, nervousness, depressive states, headaches, sleep and memory disorders, dizziness, hypesthesia and paresthesia. In addition, cerebral blood flow disorders are possible;
Sensory organs: decreased visual acuity, taste disturbance, cataract, eye irritation;
Heart and blood vessels: tachycardia, high blood pressure, palpitations, thrombophlebitis, angina pectoris, arterial thrombosis, pulmonary embolism;
Digestive tract: loss of appetite and body weight, hypercholesterolemia, vomiting and nausea, digestive and stool exams, abdominal pain, dry mouth, stomatitis and increased activity of liver enzymes;
Reproductive system: vaginal discharge, vaginal bleeding, vaginal dryness, painful sensations in the mammary glands. Lability of appetite and body weight, hypercholesterolemia, vomiting and nausea, digestive and stool exams, abdominal pain, dry mouth, stomatitis, and increased activity of liver enzymes; Reproductive system: vaginal discharge, vaginal bleeding, vaginal dryness, painful sensations in the mammary glands. Lability of appetite and body weight, hypercholesterolemia, vomiting and nausea, digestive and stool exams, abdominal pain, dry mouth, stomatitis, and increased activity of liver enzymes; Reproductive system: vaginal discharge, vaginal bleeding, vaginal dryness, painful sensations in the mammary glands.
Drug interactions
Experience with the drug letrozole with other anti-tumor drugs is not.
In vitro, cimetidine and warfarin had no effect on the efficacy and plasma concentrations of letrozole (despite the significant effects of cimetidine and warfarin on P450).
Significant interactions of letrozola with benzodiazepines, anti-inflammatory drugs, furosemide, barbiturates, and omeprazole were not observed.
Letrozole inhibits the activity of CYP2 A6 and CYP2 C19 in vitro, but there was no clinically significant interaction with diazepam (CYP2 C19 substrate). Despite the fact that the likelihood of interactions of letrozole with the isoenzyme CYP2 C19 is negligible, caution should be exercised in connection with the appointment of letrozole with substances metabolized with the participation of CYP2 C19.
Overdose
There is no clinical experience with letrozole overdose. Animal experiments show a low risk of acute intoxication with letrozole.
In clinical studies there has been the experience of a single dose of 30 mg letrozole and long-term therapy with letrozole at a dose of 5 mg / day that was not accompanied by the development of serious side effects and effects that were potentially fatal.
There is no specific antidote letrozole. In the case of acute overdose, standard clinical measures recommended for intoxication with drugs are carried out.
