Harvard Health Letter

By the way, doctor: Is it okay to switch from Avodart to finasteride for BPH?

Q. I have been taking Avodart for my BPH, along with Flomax, but finasteride may be less expensive. Should I switch?

A. The drugs used to treat benign prostatic hyperplasia (BPH) fall into two main groups, the 5-alpha-reductase inhibitors and the alpha-1 blockers. Finasteride (Proscar), which is available as a generic, and dutasteride (Avodart) are 5-alpha-reductase inhibitors. Tamsulosin (Flomax) is an alpha-1 blocker.

The 5-alpha-reductase inhibitors shrink the prostate gland by blocking the 5-alpha-reductase enzyme that converts testosterone to dihydrotestosterone, a form of the male hormone that acts on the gland. The alpha-1 blockers relax smooth muscle cells in the prostate and the bladder neck, where the urethra comes out of the bladder. The 5-alpha-reductase inhibitors may take awhile to work (six months to a year) but are effective in men with larger prostates. The alpha-1 blockers tend to improve urinary symptoms quickly and are usually prescribed for mild or moderate BPH.

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