What Is Finasteride?

Finasteride is an oral medication used to treat hair loss and noncancerous prostate enlargement in cisgender men and excessive hair growth in cisgender women. It can also be used in hormone therapy for transgender women.

It is an antiandrogen, which means it functions by stopping androgens from having an effect in the body. Finasteride specifically reduces the production of dihydrotestosterone, which is produced in several locations in the body, including in the prostate gland, scalp, and brain.

Does Finasteride Have Adverse Effects?

Although they are rare, adverse effects are known for finasteride. Some of these are reversible, which means they stop after patients stop taking the drug. However, others can persist. In both cases, these effects are rare enough that the medication is still very commonly prescribed.

The adverse effects include disruptions to sex drive and erectile dysfunction; changes in the production of steroids related to the neurological system; loss of muscular strength; breast enlargement in cisgender men; and psychological effects, including depression and increased suicidality (see the next section for a definition of this term).

Post-finasteride syndrome is sometimes used to refer to the collection of serious adverse effects that are seen in patients that take finasteride and persist after they discontinue it. Note that despite there being some literature available on post-finasteride syndrome, it is a contentious term. As pointed out in the editorial “Suicidality and Psychological Adverse Events in Patients Treated with Finasteride”, it is not recognized by the research community as a valid classification. There is even a paper that suggested that post-finasteride syndrome has only been documented in low-quality studies.

What Is Suicidality?

Suicidality is a term that covers all the aspects of suicide: ideation, which means having serious thoughts about suicide; planning; and attempts. In psychological and psychiatric research and practice, suicidality is sometimes discussed in terms of the balance between the will to live and the wish to die, with subjects ranked as nonsuicidal, or having low, moderate or high suicidality.

Note that suicidal ideation does not always imply or lead to planning or attempts. It is a difficult topic to study, because there is no universal definition of suicidal ideation. This makes it difficult to compare results from different research papers. Furthermore, healthcare records often document suicidal ideation as present or absent rather than considering the nuances of it.

Increases in suicidality of any kind in response to medication are considered an adverse effect. If researchers look at a population (a group of people with common demographic characteristics) and see that the suicidality is significantly higher in those taking a medication than in those not taking it, this is called a significant disproportionality signal for increased suicidality.

What Is the Editorial About?

The editorial “Suicidality and Psychological Adverse Events in Patients Treated with Finasteride” looks at the disproportionality signal for suicidality, depression, and other psychological adverse effects related to finasteride. The authors briefly review what is known about this important topic.

The authors have over 20 years’ experience in dermatological practice and prescribe oral finasteride for androgenetic alopecia (male hormone-related baldness). They suggest that prior to prescribing finasteride, it may be important to obtain a personal history or screen for preexisting personality disorders, since there is a significant but rare indication that finasteride could trigger or exacerbate such issues.

What Is the Takeaway Message for Patients?

Finasteride is an important medication with a range of applications, but it shouldn’t be taken lightly. Even if adverse effects are rare, they do occur. Always discuss the adverse effects with your doctor prior to taking a new medication.