5-alpha reductase inhibitors
5-alpha reductase inhibitors are prescription medicines that lower the hormone DHT in men. Finasteride 5 mg is used to treat an enlarged prostate. They take months to work, can cause sexual side effects, and must not be handled crushed by women who are or may be pregnant.
Pharmacist review in progress. This page is based on the sources listed below and is being checked by our registered pharmacist.
How do 5-alpha reductase inhibitors work?
These medicines block the enzyme that turns testosterone into DHT, a hormone that drives growth of the prostate. With less DHT, the prostate can shrink slowly.
Active ingredients of this type
These active ingredients belong to 5-alpha reductase inhibitors. They are listed A to Z.
- Finasteride: Finasteride 5 mg is a prescription medicine for an enlarged prostate in men.
Common questions
How long do they take to work?
Usually several months, so benefit is judged over a long period. Symptoms often return if the medicine is stopped. Do not stop on your own; talk to your doctor if you are worried about side effects.
Do they affect a PSA blood test?
Yes. Finasteride lowers PSA by about half within six months. Tell any doctor who orders a PSA test that you take it, because the result must be read with this in mind.
Sources
- Finasteride. NHS (UK)
- Proscar (finasteride) 5 mg: label. DailyMed, US National Library of Medicine