Finasteride – 4-azasteroid compounds, selectively and competitively inhibiting 5α-reductase. This nicotinamide adenine dinucleotide phosphate (NADP) -dependent enzyme converts testosterone to dihydrotestosterone.
Preparation isoenzymes specifically inhibits 5α-reductase type 2, which leads to a significant reduction in DHT levels in the prostate (> 90%) and in the circulation (from 60% to 80%).
Finasteride improves prostate testosterone (approximately 85%) in patients with BPH, it does not affect the growth and morphology of the prostate gland. The drug has no pronounced affinity to the androgen receptors. Finasteride significantly reduces plasma PSA level by 41% – 71% in patients with symptomatic BPH. However, the drug has no effect on the ratio of the values of unbound and total PSA.
prostate size is reduced under the influence of finasteride as a result of atrophy and apoptosis. Due to the influence of the histological changes of the drug observed after 6 months of treatment. Glandular elements prostate tissues most sensitive to finasteride. The drug lowers the tone of the detrusor in patients with urinary retention caused by benign prostatic hyperplasia.
Finasteride is well absorbed in the gastrointestinal tract, the food slows the absorption rate, but does not affect the amount of suction. Average bioavailability of finasteride is 63% (within 34 – 71%), based on the ratio of the area under the curve for intravenous reference dose. The maximum value of finasteride plasma concentration of 37 ng / ml (27 – 49%) and reached within 1 – 2 hours after administration. The drug accumulates in the body after repeated multiple introductions. The establishment of the equilibrium concentration occurs after 17 days, the exact time is not known.
Approximately 90% of finasteride is circulated in the linked state with plasma proteins. Finasteride high volume of distribution (76 l at steady state); drug penetrates the blood-brain barrier and a small amount was found in semen. The drug can be absorbed through the skin in contact with the milled tablets.
Finasteride is metabolized primarily by the liver to inactive metabolites. Plasma clearance finasteride 165 ml / min (70 -279ml / min) and the half-life of 6 hours. Approximately 39% (32 – 46%) received a dose excreted in urine as metabolites, and 57 (51 – 64%) through the intestine.
Pharmacokinetics in general does not change with increasing term renal insufficiency. Pharmacokinetics in liver failure conditions has not been studied functions.
Obolensky OP, Russia
1 film-coated tablet contains:
Finasteride 5 mg
calcium hydrogenphosphate dihydrate
sodium dodecyl sulfate,
giprolozaa (hydroxypropyl cellulose)
Treatment of benign prostatic hypertrophy.
- Hypersensitivity to finasteride and other components of the drug;
- Obstructive uropathy;
- lactose intolerance;
- lactase deficiency;
- syndrome of glucose-galactose malabsorption;
- for use in women;
- the age of 18 years.
The frequency of side effects is classified according to the recommendations of the World Health Organization: very often – at least 10%; often – at least 1% but less than 10%; infrequently – at least 0.1% but less than 1%; rarely – at least 0.01% but less than 0.1%; very rare (including sporadic cases) – less than 0.01%.
From the nervous system: rarely – drowsiness.
On the part of genitals and mammary gland: very often – impotence often -reduction libido, ejaculation disorders, decrease in ejaculate volume, and an increase in breast tenderness; rarely – pain in the testicles; very rarely – selection of mammary secretion, formation of nodules in the mammary glands. In most patients, these effects were transient.
Allergic reactions: often – skin rash; rarely – itching, urticaria, angioneurotic edema of the lips and face.
From the laboratory parameters: seldom – a decline in PSA concentration.
How to accept, acceptance rate and dosage
Inside, squeezed liquid and swallowing whole tablet (tablet can not divide and comminute), regardless of the meal.
The recommended dose is 5 mg (1 tablet) 1 time per day.
The treatment duration to 6 months, if necessary, the treatment may be continued until a clinical effect.
In patients with hepatic impairment Dose adjustment is not required.
In patients with renal failure of different severity (with a decrease QC to 9 ml / min) a dose adjustment is required.
Elderly patients No dose adjustment is required.
In a dry place, protected from light at a temperature not higher than 25 ° C
Not detected clinically significant interactions with other drugs finasteride.
The combined use of finasteride with propranolol, digoxin, glibenclamide, warfarin, theophylline, angiotensin converting enzyme inhibitors, acetaminophen, acetylsalicylic acid, alpha-blockers, beta-blockers, calcium channel blockers, nitrates, diuretics, blockers of histamine H2-receptor, HMG-CoA reductase inhibitors, nonsteroidal antiinflammatory drugs, quinolones and benzodiazepines detected clinically relevant manifestations of a medicament vzaimodeys tviya.
Finasteride is used in patients with enlarged prostate gland, whose volume is more than 40 cm3.
Patients with a large amount of residual urine and / or substantially reduced current urine should be closely monitored for obstructive uropathy.
Patients who are taking finasteride should be observed at the urologist.
Before treatment with finasteride is necessary to eliminate the disease, stimulating the growth of the prostate and the urethra obstruction – prostate cancer, urethral stricture, bladder hypotension, a violation of its innervation and infectious prostatitis.
As there is no experience in the treatment of BPH with finasteride in patients with hepatic impairment, treatment of these patients should be performed with caution, since we can not exclude the increase of finasteride plasma concentrations.
Influence on concentrations of PSA and diagnosis of prostate cancer before treatment with finasteride and periodically during the treatment process should be carried rectal examination and other methods of cancer diagnosis prostate. Determination of serum PSA is also used for prostate cancer. Initial PSA concentrations above 10 ng / ml implies a wider examination of the patient, including biopsy of the prostate.
When PSA concentration range of 4-10 ng / ml is recommended additional examination of the patient. The concentration of PSA in patients with prostate cancer and patients not having that disease, may coincide to a great extent. Therefore, in men with BPH normal value PSA concentration does not exclude prostate cancer regardless of treatment with finasteride. The initial concentration of PSA less than 4 ng / ml also allows to eliminate prostate cancer.
Finasteride causes a decrease in serum PSA concentrations by approximately 50% in patients with BPH even in the presence of prostate cancer. In this regard, it should be borne in mind that the reduction in PSA levels in patients with BPH treated with finasteride, does not rule out concomitant prostate cancer.
Patients receiving finasteride for 6 months. or more, the rate of PSA should be doubled compared with the normal values of the indicator in patients not receiving treatment. This adjustment preserves the sensitivity and specificity of the PSA analysis and the possibility of prostate cancer.
Any sustained increase in PSA levels of patients treated with finasteride, requires a thorough examination to determine the cause, including violation of the use of finasteride.
Finasteride does not significantly reduce the percentage of free PSA fraction (ratio of free PSA / total PSA). This indicator remains constant even under the influence of finasteride. If the percentage of free PSA is used, correction values of the given parameter is optional for diagnosing prostate cancer.
Influence on laboratory parameters
PSA concentration in serum is correlated with patient age and prostate volume and prostate volume, in turn, depends on the age of the patient. In determining the concentration of PSA should be noted that this figure is reduced in patients treated with finasteride.
In most patients, the rapid decline in PSA concentration observed during the first months of treatment, after which there is a stabilization of this parameter at a new value that is typically half of the values obtained before treatment. Therefore, in patients treated with finasteride for 6 months or more, you should double the PSA concentration for comparison with normal ranges in men not taking finasteride.
Effects on ability to transport management and work with technology
Caution must be exercised in controlling transportation and handling equipment due to the fact that when using the drug may cause side reaction such as drowsiness.
Pregnancy and lactation
The drug Finasteride is not indicated for women and children.
Patients received a single dose of finasteride to 400 mg and in multiple doses up to 80 mg / day for 3 months, with no adverse effects were observed.
Recommendations for specific treatment with finasteride no overdose.