Letrozole

Letrozole is an anticancer drug that works by blocking the binding of estrogen.

The drug also has an antiestrogenic effect, selectively slowing down the activity of aromatase (an important bioenzyme in the processes of estrogenic binding) through highly specific synthesis with the components of this enzyme. Together with this, the drug slows down the implementation of estrogenic biosynthesis inside healthy peripheral tissues, as well as neoplasm tissues. [1]

Indications Letrozole

It is used in postmenopausal women - in the early stages with malignant neoplasms in the breast area (expressing the endings of female sex hormones), as an additional treatment.

It is used for malignant breast lesions in the early stages, during postmenopause after completion of standard additional therapy with tamoxifen - as a prolonged additional substance.

It is prescribed for hormone-dependent malignant breast lesions (common) in postmenopausal women - 1st line therapy.

Also used in the case of malignant breast carcinoma of a widespread nature in postmenopausal women who have previously used antiestrogens.

Release form

The release of the substance is realized in tablets - 10 pieces inside a cell pack; in a box - 3 such packs.

Pharmacodynamics

In postmenopausal women, estrogens in a woman are formed mainly with the help of aromatase, which partially converts androgens formed inside the adrenal glands into estrone with estradiol.

The constant use of drugs in a daily portion of 0.1-5 mg causes a decrease in the plasma values of estradiol and estrone with estrone sulfate to a level of up to 95% of the initial values. The inhibition of the binding of estrogens must be maintained for the entire period of therapy. [2]

When the binding of estrogens is blocked, androgens, which are precursors of estrogens in terms of chemical structure, increase.

At the same time, Letrozole therapy slightly increases the likelihood of developing osteoporosis.

Adjuvant treatment in the early stages of malignant breast carcinoma reduces the likelihood of recurrence, increases 5-year progression-free survival, and reduces the risk of metastases and secondary neoplasms.

Prolonged adjunctive treatment reduces the likelihood of relapse by 42%.

Pharmacokinetics

When taken orally, the medication is at a high speed and is almost completely absorbed inside the intestine. The average bioavailability is 99.9%. Food intake reduces the rate of absorption. To achieve the Cmax values, on average, it takes 1 hour in the case of drug use on an empty stomach, or 2 hours in the case of food consumption.

Intraplasmic protein synthesis is approximately 60%. With prolonged use of the drug, its accumulation is not observed.

Most of the drug is involved in metabolic processes with the formation of a metabolic component that does not have activity.

Excretion is mainly realized in the form of metabolic elements together with urine; the smaller part is excreted by the intestines. The half-life is 2 days.

Dosing and administration

The medication is taken orally, without reference to food intake. For a day, they use 1-fold, 2.5 mg of the drug. The drug is used daily and for a long time (5 years or until a relapse occurs).

Prolonged adjuvant treatment usually lasts 4 years (maximum 5 years). If symptoms of progression of carcinoma are detected, the use of drugs must be completely canceled.

In people with carcinoma in the last phase or with manifestations of metastasis, therapy is continued until there is a pronounced development of the neoplasm.

• Application for children

The medication is not intended for pediatric use.

Use Letrozole during pregnancy

Letrozole should not be used during breastfeeding or pregnancy.

Contraindications

The main contraindications:

• hormonal status, which is noted during fertility;
• severe intolerance to the elements of the drug.

Caution is necessary in the case of use in persons with glucose-galactose malabsorption, lactose intolerance and lactase deficiency.

Side effects Letrozole

Among the side symptoms:

• lesions associated with NS: drowsiness, dysesthesia, dizziness, paresthesia, depression and nervousness, and in addition, insomnia, anxiety, hypesthesia, irritability, temporary disorders of cerebral blood flow and memory impairment;
• problems affecting the digestive tract: nausea, abdominal pain, constipation, dyspepsia, dry mouth mucous membranes, vomiting, stomatitis and diarrhea, and in addition, an increase in the activity of intrahepatic enzymes;
• violations of hematopoietic processes: leukopenia;
• respiratory disorders: cough or dyspnea;
• signs associated with blood flow: arterial thrombosis, tachycardia, stroke, thrombophlebitis affecting superficial and deep veins, pulmonary embolism, increased blood pressure, as well as ischemic heart disease;
• epidermal lesions: rashes, Quincke's edema, skin dryness, hyperhidrosis, pruritus, alopecia, anaphylactic signs and urticaria;
• disorders affecting the work of ODA: myalgia, arthritis, fractures, arthralgia, as well as osteoporosis and pain affecting the bones;
• sensory problems: cataracts, taste disturbances, and blurred vision;
• disorders affecting urogenital function: bleeding, pain affecting the sternum, increased frequency of urination, vaginal discharge and infections;
• metabolic disorders: anorexia, thirst, increase or decrease in weight, increased appetite and hypercholesterolemia;
• other manifestations: fatigue, malaise, peripheral edema, paroxysmal fever, hyperthermia, asthenia, generalized edema, dry mucous membranes and pain in the area of neoplasm foci.

Overdose

There is evidence of intoxication with Letrozole.

There are no specific methods of therapy for poisoning with this drug, therefore, symptomatic as well as supportive actions are carried out. The medication can be excreted from the body through hemodialysis.

Storage conditions

Letrozole must be stored in a place protected from moisture, children and sunlight. The temperature level is not higher than 25 ° C.

Shelf life

Letrozole is allowed to be used within a 24-month term from the date of manufacture of the therapeutic substance.

Analogs

The analogues of the medicine are the means of Femara, Aralet, Letromar and Lerza with Letrotera and Letrozole Teva, and besides this Etruzil.

Reviews

Letrozole receives little feedback from patients - people with cancer are not too willing to talk about the course of their pathology and therapy.

Oncologists, on the other hand, consider medicines from this category to be very effective (as confirmed by scientific research and testing) in the treatment of breast carcinoma.