Included in the formulation
АТХ:G.04.C.B.02 Dutasteride
Pharmacodynamics:A remedy for the treatment of benign prostatic hyperplasia. Suppresses the activity of 5α-reductase isoenzymes of the 1 st and 2 nd type, which are responsible for converting testosterone into 5α-dihydrotestosterone. Dihydrotestosterone is the main androgen responsible for the hyperplasia of the glandular tissue of the prostate gland.
The maximum effect of dutasteride on the decrease in the concentration of dihydrotestosterone is dose-dependent and is observed 1-2 weeks after the start of treatment. After 1 and 2 weeks of taking dutasteride at a dose of 0.5 mg per day, the average concentration of dihydrotestosterone in serum is reduced by 85% and 90%.
Dutasteride helps to reduce the size of the prostate gland, improves urination and reduces the risk of acute urinary retention and the need for surgical treatment.
Pharmacokinetics:Absorption - 60%. Connection with plasma proteins - 99% (albumin), 96.8% - acid α1-glycoprotein. Vd - 4.28 ± 7.14 l / kg, penetrates the blood-brain barrier and into the sperm. Biotransformation in the liver (CYP3A4 and CYP3A5) to the active (6β-hydroxydutasteride) and low-activity metabolites. The half-life is 170-300 h (1-5 weeks), characterized by an increase with age.Clearance - 2,3 ± 0,8 ml / min per 1 kg. Elimination by the kidneys (less than 1% - unchanged), mainly - with feces (40% - in the form of metabolites, 5% - unchanged).
Absolute bioavailability of dutasteride in men is about 60% with respect to a 2-hour intravenous infusion. Bioavailability of dutasteride does not depend on food intake.
Indications:Treatment and prevention of progression of benign prostatic hyperplasia.
XIV.N40-N51.N41 Inflammatory diseases of the prostate
XIV.N40-N51.N40 Hyperplasia of the prostate
XVIII.R30-R39.R33 Retention of urine
Contraindications:Hypersensitivity to dutasteride and other 5α-reductase inhibitors; prostate cancer; contraindicated in women and children.
Carefully:Caution should be used in patients with impaired liver function, since dutasteride is subject to intensive metabolism in the liver, and its half-life is 3-5 weeks.
In patients with benign prostatic hyperplasia, digital rectal examination and other methods of prostate cancer testing prior to treatment with dutasteride should be performed and periodically repeated during treatment to exclude the development of prostate cancer.
Pregnancy and lactation:Recommendations FDA category X. Contraindicated in women. Absorbed from the skin. It carries the risk of developing anomalies for male fetuses, so pregnant women or women of reproductive age should not touch capsules with the drug. Adequate and well-controlled studies on humans have not been conducted. Preclinical studies indicate that suppression of dihydrotestosterone production by dutasteride in pregnant women can disrupt the development of external genitalia in male fetuses.
There is no information on the penetration into breast milk. Do not apply!
Dosing and Administration:For adult men, including elderly patients, the recommended dose for oral administration is 500 μg once a day. Treatment should be continued for at least 6 months.
Side effects:On the part of the reproductive system: erectile dysfunction, change (decrease) of libido, ejaculation, gynecomastia (includes soreness and enlargement of the mammary glands).
Allergic reactions: rash, itching, hives, localized edema, angioedema.
From the skin and subcutaneous fat: Alopecia (mainly loss of hair on the body) or hypertrichosis.
Overdose:When administering dutasteride to 40 mg per day, no significant side effects were noted once (80 times higher than the therapeutic dose) for 7 days. During clinical trials, patients received dutasteride in a dose of 5 mg daily, while no additional side effects were observed to those observed with 0.5 mg of dutasteride.
Treatment: symptomatic and supportive, since there is no specific antidote to dutasteride.
Interaction:Because the dutasteride metabolized by the isoenzyme CYP3A4, in the presence of inhibitors of CYP3A4, the concentration of dutasteride in the blood can increase.
With the simultaneous use of dutasteride with inhibitors of CYP3A4 verapamil and diltiazem decreased clearance. At the same time, amlodipine, another blocker of calcium channels, does not reduce the clearance of dutasteride.
Special instructions:Dutasteride is absorbed through the skin, so children and women should avoid contact with the active substance. In case of such contact, immediately wash the corresponding skin area with soap and water.
Determination of concentrations Prostate-specific antigen in the serum is an important component of a complex of studies aimed at detecting prostate cancer. Baseline Prostate-specific antigen less than 4 ng / ml in patients receiving dutasteride, does not exclude the diagnosis of prostate cancer.