Finasteride (Tablets) Instructions for Use

ATC Code

G04CB01 (Finasteride)

Active Substance

Finasteride (Rec.INN registered by WHO)

Clinical-Pharmacological Group

Drug for the treatment of benign prostatic hyperplasia. 5α-reductase inhibitor

Pharmacotherapeutic Group

Drugs used in urology; drugs for the treatment of benign prostatic hyperplasia; testosterone-5-alpha-reductase inhibitors

Pharmacological Action

An inhibitor of 5-alpha reductase, the enzyme that converts testosterone into the more active dihydrotestosterone. It reduces the content of dihydrotestosterone in the blood and prostate tissue.

It suppresses the stimulating effect of dihydrotestosterone on the development of prostate adenoma.

Finasteride promotes a reduction in the size of the enlarged gland, improves urine flow, and reduces symptoms associated with benign prostatic hypertrophy. It may take several months of treatment to reduce the clinical manifestations of the disease.

Pharmacokinetics

It is well absorbed and penetrates into tissues and body fluids, and is detected in ejaculate. Bioavailability is 80% and does not depend on food intake. C_max is reached in 1-2 hours. Plasma protein binding is 90%.

It is excreted as metabolites by the kidneys (39%) and through the intestines (57%). T_1/2 is 6-8 hours. Long-term (3-7 months) administration at a dose of 5 mg/day reduces the concentration of 5-alpha-dihydrotestosterone in blood serum by 70%.

Indications

Benign prostatic hyperplasia (to reduce the size of the prostate gland; improve urine flow and reduce symptoms associated with hyperplasia; reduce the risk of acute urinary retention requiring catheterization or surgical intervention, including transurethral resection of the prostate and prostatectomy).

ICD codes

Dosage Regimen

Take one 5 mg tabletorally once daily.

Administer the dose with a glass of water, with or without food, as food intake does not significantly affect bioavailability.

Continue treatment long-term, as a minimum of 6 months is usually required to assess therapeutic efficacy and observe a reduction in prostate size and improvement in urinary symptoms.

Swallow the tablet whole; do not crush or chew it.

If a dose is missed, take it as soon as remembered unless it is almost time for the next scheduled dose. Do not take a double dose to make up for a forgotten one.

Regular monitoring, including digital rectal examination, is required during therapy.

Do not discontinue treatment without consulting a physician, as symptoms may return.

Adverse Reactions

From the reproductive system: rarely – impotence, decreased libido, decreased volume of ejaculate, gynecomastia.

Allergic reactions: skin rash, angioedema are possible.

Contraindications

Hypersensitivity to finasteride, obstructive uropathy, prostate cancer. Finasteride is not used in women and children.

Use in Pregnancy and Lactation

Women of childbearing age and pregnant women should avoid contact with the drug, as it has teratogenic properties (the ability to suppress the conversion of testosterone to dihydrotestosterone can cause impaired development of the genital organs in a male fetus) and penetrates into seminal fluid.

Use in Hepatic Impairment

Finasteride should be used with caution in hepatic insufficiency.

Pediatric Use

The drug is not used in children.

Special Precautions

Finasteride should be used with caution in hepatic insufficiency.

In the presence of a large volume of residual urine and/or a sharply reduced urine flow, the development of obstructive uropathy should be considered.

Before starting treatment with finasteride and periodically during treatment, a digital rectal examination and examination by other methods for the presence of prostate cancer should be performed.

Drug Interactions

No clinically significant interaction of finasteride with propranolol, digoxin, glibenclamide, warfarin, theophylline, and antipyrine has been found.

Apparently, Finasteride does not have a significant effect on the cytochrome P450 enzyme system and, accordingly, does not affect the pharmacokinetic parameters of drugs metabolized by hepatic microsomal enzymes.

No clinically significant drug interaction was observed with the simultaneous use of finasteride with ACE inhibitors, alpha-blockers, beta-blockers, calcium channel blockers, nitrates, diuretics, histamine H₂-receptor blockers, HMG-CoA reductase inhibitors, NSAIDs, quinolones, and benzodiazepines.

Storage Conditions

Store at 2°C (36°F) to 25°C (77°F). Keep in original packaging, protected from light. Keep out of reach of children.

Dispensing Status

Rx Only

Important Safety Information

This information is for educational purposes only and does not replace professional medical advice. Always consult your doctor before use. Dosage and side effects may vary. Use only as prescribed.