Finasteride(CAS: 98319-26-7) 

Medical uses Benign prostatic hyperplasia

Physicians use finasteride for the treatment of benign prostatic hyperplasia (BPH), informally known as an enlarged

prostate. The FDA-approved dose is 5 mg once a day. Six months or more of treatment with finasteride may be

required to determine the therapeutic results of treatment. If the drug is discontinued, any therapeutic benefits reverse

within about 6–8 months. Finasteride may improve the symptoms associated with BPH such as difficulty urinating,

getting up during the night to urinate, hesitation at the start of urination, and decreased urinary flow.

Adverse effects

In a four year controlled clinical study, 3040 patients with symptomatic benign prostatic hyperplasia were treated with

5 mg per day finasteride or placebo. Discontinuation rates due to adverse reactions related to sexual function were 3.7%

in the finasteride arm and 2.1% in the placebo arm. Sexual effects were the most common type of adverse reaction.

In 12 month duration double-blind clinical trials including more than 3000 patients, adverse effects included decreased

libido (5% in the finasteride group and 3% in the placebo group), erectile dysfunction (8% finasteride, 3% placebo),

and ejaculation disorder (2% finasteride, 0.6% placebo).

Anxiety and depression

Mood disorders were not observed as an important adverse effect in the phase 3 trials leading to regulatory approval of

finasteride for the treatment of benign prostatic hyperplasia.Nonetheless, regulatory authorities have listed mood disorders

as among the possible adverse effects of finasteride, and a variety of small studies have suggested a possible connection.

In a small study examining the use of finasteride to treat hirsutism in women, fewer patients in the finasteride-treated group

reported depression relative to the control group.

Another study with a larger sample size of 128 men, though no women, also at a dose of 1 mg per day, found that finasteride

increased both BDI and HADS depression scores significantly. The authors concluded that finasteride should be

prescribed cautiously to patients at a high risk of depression.

A study comparing depression in impotent men with a history of exposure to finasteride found that they experienced

greater depression and suicidal ideation relative to non-impotent men without a history of finasteride exposure. The

authors did not comment on the relative extent to which sexual dysfunction and prior finasteride treatment might

have contributed to the depression.