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Fazlodex
Last reviewed: 03.07.2025
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Indications Fazlodex
Faslodex is prescribed for metastatic and rapidly progressing forms of breast cancer, for oncological diseases that have a positive perception of estrogens (estrogen-dependent breast cancer in patients).
Most often it is used in the climacteric period, when the pathology develops simultaneously with or after the end of treatment with antiestrogenic drugs.
Faslodex is not indicated in young people: it is usually used to treat adults and elderly women.
Release form
The drug Faslodex is intended for intramuscular injection.
It is produced and released in a special disposable syringe made of glass material with a convenient system of use. The syringe contains 5 ml of the drug, packed in a transparent cell package in the amount of 1 piece, a sterile needle in a protected package is supplied in the kit. The drug is dispensed in a cardboard box.
The active ingredient of the drug is fulvestrant, in the amount of 0.25 g. Additional substances are ethanol 96% - 0.5 g, benzyl alcohol - 0.5 g, benzyl benzoate - 0.75 g / ml, castor oil, brought to 5 ml.
The preparation is a transparent, possibly slightly yellowish, slightly viscous (due to castor oil) liquid.
Pharmacodynamics
Pharmacodynamics of Faslodex is determined by the action of the active component of the drug - a substance that has antagonist properties with the estrogen receptor. In terms of the strength of interaction with receptors, it has a similar effect to estradiol. The active substance stops the trophic effect of estrogens, without revealing independent, estrogen-like, activity.
The principle of the drug's action is based on the suppression of active activity and regression of estrogen receptors.
In addition, the active component of Faslodex confidently reduces the expression of progesterone receptors. During the administration of the drug, there is no stimulation of the endometrium during the postmenopausal period.
The effect of the drug on endometrial tissue during long-term treatment has not been assessed, as well as possible changes in tissue structure.
No studies have been conducted on the effects of long-term therapy with the drug on bone tissue.
Pharmacokinetics
When administered intramuscularly, the drug is absorbed gradually. The maximum amount of the active component is detected only after a week. The use of Faslodex in a dosage of 0.5 g provides an optimal balance during the first 4 weeks of use. The balance provides for fluctuations in the level of the active substance in the plasma in a fairly narrow range: max and min readings can differ by approximately 3 times.
When administered intramuscularly, the ratio may be proportional to the administered dosage of the drug (in the range of 0.05-0.5 g).
The active substance is distributed in the body quite quickly, mainly outside the vessels. It binds to plasma proteins by 99%. The main components of the binding consist of low-density, medium-density and high-density lipoprotein fractions.
The metabolic properties of the active substance of the drug consist of a combination of a large number of possible ways of biological transformation, identical to the metabolic schemes of endogenous steroid hormones. The determined metabolites may be somewhat more passive than the active substance.
The active component of the drug is mostly excreted with feces, about 1% can be excreted through the kidneys. The clearance of the substance implies a high degree of extraction in the liver. The half-life is determined to be 50 days.
The pharmacokinetics of Faslodex do not change depending on the patient's age category, weight, or race.
Dosing and administration
Faslodex is intended for intramuscular use. Method of administration: slow (over 2 minutes) injection. If 2 doses are required, the drug is administered first into one, then into the other gluteal muscle.
Adults and elderly patients are administered the drug in the amount of 0.25-0.5 g once every 30 days. It is possible to initially administer Faslodex at 0.5 g twice during the month, with an interval of 14-15 days.
The drug is not used in children and adolescents.
In case of liver and urinary system diseases, there is no need to change the dosage of the drug.
Warning: The needle supplied with the anti-estrogen does not require additional sterilization. Do not touch the needle during the entire period of administration of the drug.
Application scheme:
- we take the transparent syringe out of the packaging cell and inspect it for cracks and chips;
- we print out the outer needle protection;
- break off the partition of the white plastic cap of the syringe cannula and remove the cap together with the rubber stopper;
- Using the rotation method, attach the needle to the syringe cannula;
- remove the needle guard, do this carefully, trying not to catch the end of the needle;
- by lightly pressing, release excess bubbles from the syringe cavity;
- we make an injection into the outer upper quadrant of the buttock, we administer the drug slowly (up to 2 minutes);
- remove the needle and press the special lever, moving it to the extreme forward position to close the end of the needle. If this manipulation fails, then simply place the needle in the needle container to prevent possible contact of the drug residue with the skin.
The procedure should be carried out with the utmost care, the injection should be performed with gloves. No strangers should be allowed to perform the procedure: the administration of the drug should be supervised by a competent medical specialist.
Use Fazlodex during pregnancy
The drug is prohibited for use during pregnancy and breastfeeding.
Contraindications
Contraindications to the use of Faslodex are:
- allergic reactions to the active or any additional substance of the drug;
- severe form of functional liver disorder;
- period of pregnancy and breastfeeding;
- children under 18 years of age.
Caution should be exercised when prescribing the drug to patients with urinary system disorders.
Side effects Fazlodex
The drug Faslodex may cause some side effects, which we list in order of decreasing frequency:
- attacks of nausea;
- diarrhea, weight loss, loss of appetite, vomiting;
- periodic attacks of "heat", cases of thromboembolism;
- skin rashes;
- signs of an inflammatory reaction at the injection site;
- cystitis, urethritis;
- thrush, vaginal discharge;
- increased activity of ALT, AST, alkaline phosphatase;
- high bilirubin levels;
- headaches, swelling.
After stopping the drug, side effects usually disappear.
Overdose
There have been no reports of overdose with Faslodex.
In animal experiments in which large doses of Faslodex were administered, only direct and indirect signs of suppression of the functional capacity of estrogens were observed.
Treatment for overdose is carried out depending on the symptoms identified.
Interactions with other drugs
Based on the results of the experimental interaction of Faslodex and Midazolam, there is no suppression of the activity of cytochrome P450 3A4. The information obtained allows us to conclude that the active substance of the drug does not affect cytochrome P450 1A2, 2D6, 2C9 and 2C19. The effect on other cytochromes was not observed.
During the experimental experience of combined action of Faslodex with such drugs as Rifampicin and Ketoconazole, no obvious changes in the clearance of the active substance of Faslodex were observed. From this it can be concluded that the use of Faslodex simultaneously with drugs that induce or inhibit cytochrome P450 3A4 does not require a revision of the dosage of the drug.
Shelf life
The shelf life of the drug under proper storage conditions is up to 4 years. Do not use this medicine if its shelf life has expired or if the blister pack or the glass syringe itself is damaged.
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Attention!
To simplify the perception of information, this instruction for use of the drug "Fazlodex" translated and presented in a special form on the basis of the official instructions for medical use of the drug. Before use read the annotation that came directly to medicines.
Description provided for informational purposes and is not a guide to self-healing. The need for this drug, the purpose of the treatment regimen, methods and dose of the drug is determined solely by the attending physician. Self-medication is dangerous for your health.