Urology · 5α-reductase inhibitor
Finasteride
Dose
5 mg PO OD for BPH; 1 mg OD for androgenetic alopecia.
Use
Symptomatic BPH with prostate >30 mL; reduces retention and surgery risk.
Monitoring
PSA halves after 6 months — double the measured value when interpreting.
Side effects
- • Reduced libido
- • Erectile dysfunction
- • Gynaecomastia
- • Persistent post-finasteride symptoms (rare)
Always confirm dose against your local formulary / BNF before prescribing.
