Finasteride 1mg is a synthetic 4-azasteroid compound that acts as a specific, competitive inhibitor of Type II 5α-reductase, an intracellular enzyme that converts testosterone to the potent androgen dihydrotestosterone (DHT). It is primarily indicated for the treatment of male pattern hair loss (androgenetic alopecia) in men. In the Indian context, it is widely prescribed by dermatologists and is available as a Schedule H drug, requiring a valid prescription.
Adult: 1 mg orally once daily, with or without food.
Note: Tablet should be swallowed whole with a glass of water. It can be taken at any time of day, but it is advisable to take it at the same time each day to maintain consistent blood levels. Do not crush or break tablets, especially if handled by women of childbearing potential.
Finasteride is a competitive and specific inhibitor of steroid Type II 5α-reductase, the intracellular enzyme that converts testosterone to the more potent androgen, 5α-dihydrotestosterone (DHT). In the scalp, DHT is believed to miniaturize hair follicles, leading to the progressive hair loss seen in androgenetic alopecia. By inhibiting the formation of DHT, finasteride decreases scalp and serum DHT concentrations, interrupting a key factor in the pathogenesis of hair loss.
Pregnancy: CATEGORY X. Contraindicated. Can cause abnormalities of the external genitalia in a male fetus if absorbed by a pregnant woman. Women of childbearing potential should not handle crushed or broken tablets.
Driving: Finasteride is not expected to affect the ability to drive or operate machinery. However, individuals experiencing dizziness or other CNS effects should exercise caution.
| Strong CYP3A4 Inhibitors (e.g., Ketoconazole, Itraconazole, Ritonavir, Clarithromycin) | May increase finasteride plasma concentrations. Clinical significance for the 1mg dose is likely minimal but monitoring is advised. | Moderate |
| Alpha-blockers (e.g., Tamsulosin, Terazosin) - for BPH | No significant interaction with the 1mg dose. (Note: 5mg finasteride is used in combination with alpha-blockers for BPH). | Minor |
| Saw Palmetto (Herbal Supplement) | Theoretical pharmacodynamic interaction as both may affect 5α-reductase. Combined use is not recommended. | Moderate |
| Oral Contraceptives / Hormonal Therapies | No known pharmacokinetic interaction. However, finasteride is contraindicated in pregnant women. | Major (for pregnancy risk) |
Same composition (Finasteride (1mg)), different brands: