Introduction

What is the truth about finasteride? The article “Risk of erectile dysfunction associated with use of 5-α reductase inhibitors for benign prostatic hyperplasia or alopecia: population based studies using the Clinical Practice Research Datalink” by Hagberg et al., has made an important contribution to hair loss treatment in men (1). As a recent investigation into the safety of finasteride, it has helped answer questions about the potential side effects of this medication.

New Literature

For men with receding hairlines, there are a few options available to allow them to keep their hair on their heads. These consist of both surgical and two FDA-approved medications, minoxidil and finasteride. But what about reports that finasteride might be linked to sexual dysfunction? A clinical trial supported these claims when it showed that a slightly higher proportion of patients treated with finasteride reported symptoms of sexual dysfunction compared to those who received placebo treatment (2). Examining a database set up to keep track of all side effects reported by consumers, their doctors and drug companies showed that a disproportionate amount of men taking either finasteride (3) or dutasteride (similar drug) (4) were reporting sexual dysfunction. The original clinical trials which concluded that finasteride was safe were critiqued for inadequate methods (5). This phenomenon was soon given a name, Post-Finasteride Syndrome (PFS). But what was PFS? In addition to sexual dysfunction, PFS was also suspected of causing a plethora of additional undesirable symptoms including fatigue, muscle weakness, and cognitive problems (6,7).  Not only were the symptoms diverse, but so was the onset and duration. Sometimes symptoms showed up at the same time as or shortly after starting finasteride. Sometimes patients had already been taking finasteride regularly when symptoms started. Sometimes symptoms didn’t appear until after a patient stopped taking finasteride and continued long after. PFS ended up a mystery. In some large trials, especially when used at a higher dosage which is sometimes prescribed to treat benign prostate hyperplasia, there was a correlation with finasteride and sexual dysfunction (8–15) but these results were in contrast with what was actually being observed in clinics (16) and the evidence from the scientific community (17). What was going on?

This article by Hagberg et al., was a turning point. Hagberg et al., looked at a population that was taking the higher dosage of finasteride for benign prostate hyperplasia and showed that sexual dysfunction was correlated with disease progression and not treatment (1). The correlation to finasteride was an artifact of treatment guidelines where those who had benign prostate hyperplasia the longest were most likely to be prescribed finasteride and were also the most vulnerable, while those patients who were more recently diagnosed were more likely to be prescribed an alternate treatment. Hagberg et al., also showed there was no increased risk of sexual dysfunction for patients taking finasteride at the lower dosage for hair loss.

With some explanation on how finasteride could be connected to sexual dysfunction, this article was an important step to maintaining the limited options for hair loss treatment. In a second article, Haber et al., continued the momentum (18). Haber et al., confirmed that finasteride at the lower dosage prescribed for hair loss was not related to reports of sexual dysfunction. Instead, both age and self-reporting of reduced libido were indicated.

Take away

So what does this all mean? There can be many causes for sexual dysfunction but finasteride probably isn’t one of them. Although you can find articles across the internet that tell you otherwise, the investigations by Hagberg et al., and Haber et al., provide support for the clinical trials which concluded finasteride safe for use.  As with any prescription medication, if you are interested in trying finasteride, make sure to consult your doctor or health care provider before proceeding.

References

1. Hagberg KW, Divan HA, Persson R, Nickel JC, Jick SS. Risk of erectile dysfunction associated with use of 5-α reductase inhibitors for benign prostatic hyperplasia or alopecia: population based studies using the Clinical Practice Research Datalink. BMJ. 2016 Sep 22;354:i4823.
2. Kaufman KD, Olsen EA, Whiting D, Savin R, DeVillez R, Bergfeld W, et al. Finasteride in the treatment of men with androgenetic alopecia. Finasteride Male Pattern Hair Loss Study Group. J Am Acad Dermatol. 1998 Oct;39(4 Pt 1):578–89.
3. Gupta AK, Carviel J, MacLeod MA, Shear N. Assessing finasteride-associated sexual dysfunction using the FAERS database. J Eur Acad Dermatol Venereol JEADV. 2017 Jun;31(6):1069–75.
4. Gupta AK, Carviel J, Gupta MA, Shear NH. Assessing dutasteride-associated sexual dysfunction using the U.S. Food and Drug Administration Adverse Event Reporting System. J Eur Acad Dermatol Venereol JEADV. 2017 Dec 1;
5. Belknap SM, Aslam I, Kiguradze T, Temps WH, Yarnold PR, Cashy J, et al. Adverse Event Reporting in Clinical Trials of Finasteride for Androgenic Alopecia: A Meta-analysis. JAMA Dermatol. 2015 Jun;151(6):600–6.
6. Healy D, Le Noury J, Mangin D. Enduring sexual dysfunction after treatment with antidepressants, 5α-reductase inhibitors and isotretinoin: 300 cases. Int J Risk Saf Med. 2018;29(3–4):125–34.
7. Irwig MS, Kolukula S. Persistent sexual side effects of finasteride for male pattern hair loss. J Sex Med. 2011 Jun;8(6):1747–53.
8. McConnell JD, Roehrborn CG, Bautista OM, Andriole GL, Dixon CM, Kusek JW, et al. The long-term effect of doxazosin, finasteride, and combination therapy on the clinical progression of benign prostatic hyperplasia. N Engl J Med. 2003 Dec 18;349(25):2387–98.
9. Gormley GJ, Stoner E, Bruskewitz RC, Imperato-McGinley J, Walsh PC, McConnell JD, et al. The effect of finasteride in men with benign prostatic hyperplasia. 1992. J Urol. 2002 Feb;167(2 Pt 2):1102–7; discussion 1108.
10. Andersen JT, Ekman P, Wolf H, Beisland HO, Johansson JE, Kontturi M, et al. Can finasteride reverse the progress of benign prostatic hyperplasia? A two-year placebo-controlled study. The Scandinavian BPH Study Group. Urology. 1995 Nov;46(5):631–7.
11. Marberger MJ. Long-term effects of finasteride in patients with benign prostatic hyperplasia: a double-blind, placebo-controlled, multicenter study. PROWESS Study Group. Urology. 1998 May;51(5):677–86.
12. McConnell JD, Bruskewitz R, Walsh P, Andriole G, Lieber M, Holtgrewe HL, et al. The effect of finasteride on the risk of acute urinary retention and the need for surgical treatment among men with benign prostatic hyperplasia. Finasteride Long-Term Efficacy and Safety Study Group. N Engl J Med. 1998 Feb 26;338(9):557–63.
13. Thompson IM, Goodman PJ, Tangen CM, Lucia MS, Miller GJ, Ford LG, et al. The influence of finasteride on the development of prostate cancer. N Engl J Med. 2003 Jul 17;349(3):215–24.
14. Wessells H, Roy J, Bannow J, Grayhack J, Matsumoto AM, Tenover L, et al. Incidence and severity of sexual adverse experiences in finasteride and placebo-treated men with benign prostatic hyperplasia. Urology. 2003 Mar;61(3):579–84.
15. Kaplan SA, Lee JY, Meehan AG, Kusek JW. Time Course of Incident Adverse Experiences Associated with Doxazosin, Finasteride and Combination Therapy in Men with Benign Prostatic Hyperplasia: The MTOPS Trial. J Urol. 2016 Jun;195(6):1825–9.
16. Tosti A, Piraccini B, Soli M. Evaluation of sexual function in subjects taking finasteride for the treatment of androgenetic alopecia. J Eur Acad Dermatol. 2001 Sep;15(5):418–21.
17. Liu L, Zhao S, Li F, Li E, Kang R, Luo L, et al. Effect of 5α-Reductase Inhibitors on Sexual Function: A Meta-Analysis and Systematic Review of Randomized Controlled Trials. J Sex Med. 2016;13(9):1297–310.
18. Haber RS, Gupta AK, Epstein E, Carviel JL, Foley KA. Finasteride for androgenetic alopecia is not associated with sexual dysfunction: a survey-based, single-centre, controlled study. J Eur Acad Dermatol Venereol JEADV. 2019 Jul;33(7):1393–7.