Origins of Finasteride
Finasteride is a synthetic drug developed in the late 1980s by Merck & Co., initially as a treatment for benign prostatic hyperplasia (BPH), or an enlarged prostate. It was discovered during research into steroid metabolism, specifically focusing on the enzyme 5-alpha-reductase. This enzyme converts testosterone into dihydrotestosterone (DHT), a more potent androgen linked to conditions like prostate enlargement and male-pattern baldness. By inhibiting this enzyme, finasteride reduces DHT levels, effectively addressing these conditions.
The drug was first approved by the U.S. Food and Drug Administration (FDA) in 1992 for treating BPH under the brand name Proscar. Later, in 1997, it was approved at a lower dose under the brand name Propecia for treating male-pattern hair loss.
Properties of Finasteride
1. Chemical Structure
- Finasteride is a 4-azasteroid compound, structurally similar to natural steroids.
- Chemical formula: C23H36N2O2
- Molecular weight: 372.55 g/mol
2.Mechanism of Action
- It is a selective inhibitor of type II 5-alpha-reductase, an enzyme that converts testosterone into DHT.
- By lowering DHT levels, finasteride reduces its impact on androgen-sensitive tissues, such as the prostate and hair follicles.
3.Pharmacokinetics
- Absorption: Oral administration with good bioavailability.
- Metabolism: Primarily in the liver via cytochrome P450 enzymes.
- Elimination: Excreted through feces and urine.
4.Dosages
- 1 mg/day for androgenic alopecia (hair loss).
- 5 mg/day for benign prostatic hyperplasia.
5.Formulations
- Typically available in tablet form.
Introduction and Uses of Finasteride
1.Benign Prostatic Hyperplasia (BPH)
- Finasteride was introduced to treat symptoms like urinary retention, frequent urination, and the need for surgery in severe cases.
- It helps by reducing prostate size and improving urinary flow.
2.Androgenic Alopecia (Male-Pattern Baldness)
- In 1997, finasteride became widely popular for hair loss prevention in men. It works by maintaining hair density and slowing hair thinning.
3.Other Off-Label Uses
- Some studies have explored its role in treating hormonal disorders like hirsutism in women, though this use is less common.
Considerations
While finasteride is effective for its approved uses, it has side effects, including reduced libido, erectile dysfunction, and, in rare cases, depression. Its effects are reversible upon discontinuation in most individuals, but some reports suggest persistent side effects, known as Post-Finasteride Syndrome (PFS), in a small subset of users.
The introduction of finasteride revolutionized the management of BPH and male-pattern baldness, offering a non-surgical alternative to addressing these conditions.