What is the use of Finasteride (Propecia)?

From the Guidelines

Finasteride is a medication primarily used to treat male pattern baldness and enlarged prostate (benign prostatic hyperplasia), with a recommended dose of 1mg daily for hair loss and 5mg daily for prostate issues, as supported by the most recent study 1.

Key Points

• Finasteride works by inhibiting the enzyme 5-alpha-reductase, which converts testosterone to dihydrotestosterone (DHT), a hormone that contributes to hair loss and prostate enlargement.
• By reducing DHT levels, finasteride can slow or stop hair loss and even promote some regrowth in many men, while also reducing prostate size and improving urinary symptoms, as shown in the study 1.
• Side effects may include decreased libido, erectile dysfunction, and decreased ejaculate volume, though these occur in only a small percentage of users, as reported in the study 1.
• Women who are pregnant or may become pregnant should not handle crushed tablets due to potential risks to male fetuses.
• Results for hair loss typically take 3-6 months to become noticeable, and the medication must be continued long-term as benefits will reverse if treatment is stopped, as stated in the study 1.

Important Considerations

• The use of finasteride for prostate cancer chemoprevention is still being researched, with some studies suggesting a potential increase in high-grade prostate cancers, as discussed in the study 1.
• However, the most recent study 1 provides the strongest evidence for the use of finasteride in treating benign prostatic hyperplasia, and its findings should be prioritized in clinical decision-making.
• Men taking finasteride should be fully informed of the potential benefits and risks, including the uncertainty surrounding high-grade cancers, as emphasized in the study 1.
• The medication should be used under the guidance of a healthcare professional, with regular monitoring of prostate-specific antigen (PSA) levels and other health indicators, as recommended in the study 1.

From the FDA Drug Label

The development and enlargement of the prostate gland is dependent on the potent androgen, 5α -dihydrotestosterone (DHT). Finasteride is a competitive and specific inhibitor of Type II 5α-reductase with which it slowly forms a stable enzyme complex. In patients with BPH, finasteride tablets have no effect on circulating levels of cortisol, prolactin, thyroid-stimulating hormone, or thyroxine. Adult males with genetically inherited Type II 5α -reductase deficiency also have decreased levels of DHT. Except for the associated urogenital defects present at birth, no other clinical abnormalities related to Type II 5α -reductase deficiency have been observed in these individuals These individuals have a small prostate gland throughout life and do not develop BPH In patients with BPH treated with finasteride (1 to 100 mg/day) for 7 to 10 days prior to prostatectomy, an approximate 80% lower DHT content was measured in prostatic tissue removed at surgery, compared to placebo;

The use of Finasteride is to treat Benign Prostatic Hyperplasia (BPH) by reducing the size of the prostate gland. This is achieved by inhibiting the production of Dihydrotestosterone (DHT), a potent androgen that contributes to the development and enlargement of the prostate gland 2.

From the Research

Uses of Finasteride

• Finasteride is used to treat benign prostatic hyperplasia (BPH) by reducing prostatic dihydrotestosterone (DHT) levels and prostate size, resulting in improvements in peak urinary flow rate and urological symptoms 3
• It is also used to treat male pattern hair loss (androgenetic alopecia) by inhibiting the conversion of testosterone to dihydrotestosterone (DHT), which is implicated in the development of hair loss 4, 5, 6
• Finasteride has been shown to promote hair growth and prevent further hair loss in a significant proportion of men with male pattern hair loss 4, 5, 6

Benefits and Risks

• The benefits of finasteride therapy appear to outweigh the risks, with most adverse events being related to sexual dysfunction (decreased libido, ejaculation disorders, and impotence) and occurring in only a small proportion of patients 3
• Finasteride is generally well-tolerated, with a favorable adverse event history 4, 6
• However, there is a concern about the use of finasteride in young fertile patients due to its action on testosterone metabolism, which may affect semen quality 7

Treatment Considerations

• A trial period of 6 or possibly 12 months is necessary to assess patient responsiveness to finasteride therapy for BPH 3
• Thorough pretreatment assessment and periodic follow-up examinations for malignancy are required in clinical practice when using finasteride to treat BPH 3
• The role of finasteride in the treatment of patients with BPH is still emerging and will no doubt gain clarity with further planned investigations 3