Finasteride

What it is and how it works

Mechanism of Action The development and enlargement of the prostate gland is dependent on the potent androgen, 5α-dihydrotestosterone (DHT). Type II 5α-reductase metabolizes testosterone to DHT in the prostate gland, liver and skin. DHT induces androgenic effects by binding to androgen receptors in the cell nuclei of these organs. Finasteride is a competitive and specific inhibitor of Type II 5α-reductase with which it slowly forms a stable enzyme complex. Turnover from this complex is extremely slow (t½ ~ 30 days). This has been demonstrated both in vivo and in vitro . Finasteride has no affinity for the androgen receptor.

Mechanism class: 5-alpha Reductase Inhibitors

Indications

Finasteride tablets is a 5α-reductase inhibitor, indicated for the treatment of symptomatic benign prostatic hyperplasia (BPH) in men with an enlarged prostate to : Improve symptoms Reduce the risk of acute urinary retention Reduce the risk of the need for surgery including transurethral resection of the prostate (TURP) and prostatectomy. Finasteride tablets administered in combination with the alpha-blocker doxazosin is indicated to reduce the risk of symptomatic progression of BPH (a confirmed ≥4 point increase in American Urological Association (AUA) symptom score) . Limitations of Use: Finasteride tablets is not approved for the prevention of prostate cancer . Monotherapy Finasteride tablets are indicated for the treatment of symptomatic benign prostatic hyperplasia (BPH) in men with an enlarged prostate to: - Improve symptoms - Reduce the risk of acute urinary retention - Reduce the risk of the need for surgery including transurethral resection of the prostate (TURP) and prostatectomy.

Dosage and administration (summary)

Finasteride tablets may be administered with or without meals. Finasteride tablets may be administered with or without meals . Monotherapy: One tablet (5 mg) taken once a day . Combination with Doxazosin: One tablet (5 mg) taken once a day in combination with the alpha-blocker doxazosin . Monotherapy The recommended dose of finasteride tablet is one tablet (5 mg) taken once a day . Combination with Alpha-Blocker The recommended dose of finasteride tablets is one tablet (5 mg) taken once a day in combination with the alpha-blocker doxazosin .

Contraindications

Finasteride tablets are contraindicated in the following: Hypersensitivity to any component of this medication. Pregnancy. Finasteride use is contraindicated in women when they are or may potentially be pregnant. Because of the ability of Type II 5α-reductase inhibitors to inhibit the conversion of testosterone to 5α-dihydrotestosterone (DHT), finasteride may cause abnormalities of the external genitalia of a male fetus of a pregnant woman who receives finasteride.

Warnings and precautions

Finasteride reduces serum prostate specific antigen (PSA) levels by approximately 50%. However, any confirmed increase in PSA while on finasteride may signal the presence of prostate cancer and should be evaluated, even if those values are still within the normal range for men not taking a 5α-reductase inhibitor . Finasteride may increase the risk of high-grade prostate cancer (5.2 , 6.1) . Women should not handle crushed or broken finasteride tablets when they are pregnant or may potentially be pregnant due to potential risk to a male fetus (5.3 , 8.1 , 16) .

Pregnancy

Pregnancy Pregnancy Category X. Finasteride are contraindicated for use in women who are or may become pregnant. Finasteride is a Type II 5α-reductase inhibitor that prevents conversion of testosterone to 5α-dihydrotestosterone (DHT), a hormone necessary for normal development of male genitalia.

Storage and supply

Finasteride tablets USP, 5 mg are blue color, film coated, round tablets debossed with ‘IG’ on one side ‘412’ on other. They are supplied as follows: NDC 76282-412-30 bottles of 30 NDC 76282-412-90 bottles of 90 NDC 76282-412-05 bottles of 500 NDC 76282-412-10 bottles of 1000 Storage and Handling Store at 20° to 25°C (68° to 77°F) .

Source: Finasteride (Finasteride) — US FDA prescribing information, 2020-10-30, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.