5-alpha-reductase inhibitors
- Block testosterone → DHT conversion
- Finasteride: BPH + male hair loss
- Dutasteride: stronger type 1 + 2 blockade
- BPH benefit takes months, not days
- combine with alpha-1 blocker if needed
- Sexual dysfunction can occur
- PSA falls ~50% → interpret accordingly
Class at a glance
- Block testosterone → DHT conversion
Clinical role
- Finasteride: BPH + male hair loss
- Dutasteride: stronger type 1 + 2 blockade
Other clinical roles
- BPH benefit takes months, not days
- combine with alpha-1 blocker if needed
Safety / monitoring
- Sexual dysfunction can occur
- PSA falls ~50% → interpret accordingly
Self-check
- What does finasteride treat?
BPH and male hair loss. - About how much do 5-alpha-reductase inhibitors lower PSA?
About 50%.
Drugs in this class (2)
5-alpha-reductase inhibitors prescription history
Animated chart of estimated U.S. prescriptions per year, BPH meds (1987–2026). 5-alpha reductase inhibitor highlighted from 1992.
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