피나스테리드
B
Finasteride
Finasteride
Oral
Finasteride is a selective type II 5α-reductase inhibitor that reduces DHT levels by approximately 65-70% by blocking the conversion of testosterone to dihydrotestosterone. Used as adjunctive therapy in transfeminine HRT, primarily for hair loss and excessive body hair.
Mechanism
섹션 제목: “Mechanism”Finasteride selectively inhibits type II 5α-reductase (primarily found in hair follicles and prostate), reducing serum DHT by ~65-70% while having virtually no effect on testosterone levels.
Compared to dutasteride, finasteride inhibits only one isoform, resulting in less DHT reduction but also potentially fewer side effects.
Dosing
섹션 제목: “Dosing”| Indication | Dose | Notes |
|---|---|---|
| Hair loss (adjunct to HRT) | 1 mg/day | Combined with HRT regimen |
| Alternative dose | 5 mg/day | Some clinicians use higher doses, but additional benefit is unclear |
- Start at 1 mg/day, the standard hair loss dose
- 5 mg tablets (Proscar) are often cheaper and can be quarter-split
- Onset typically requires 3-6 months
Brands & Availability
섹션 제목: “Brands & Availability”| Brand | Strength | Notes |
|---|---|---|
| Propecia | 1 mg | Hair loss indication |
| Proscar | 5 mg | BPH indication, can be split |
| Generics | 1 mg / 5 mg | Widely available globally |
Monitoring
섹션 제목: “Monitoring”- T: Continue routine HRT monitoring every 3 months
- DHT (optional): Can confirm 5αRI effect
- Liver function: Finasteride rarely causes hepatic injury; no additional monitoring usually needed
- PSA: Finasteride reduces PSA by ~50%; inform your doctor if PSA is being tested
Contraindications
섹션 제목: “Contraindications”- Finasteride allergy
- Severe hepatic impairment
- Pregnant partners must not handle crushed/broken tablets (teratogenic to male fetuses — typically not relevant in trans HRT context)