Finasteride, an inhibitor of the enzyme 5alpha-reductase, prescribed for benign prostatic hyperplasia and androgenetic alopecia, induces a wide variety of side effects during treatment and upon withdrawal, like sexual dysfunction and cognitive and psychological disorders, inducing the so-called post-finasteride syndrome (PFS). Here, we explored the behavioral effects of this drug in adult male rats after subchronic finasteride treatment (20 days) and at drug discontinuation (1 month). We employed multiple behavioral paradigms, including the open field test and elevated plus maze to assess locomotor activity and anxiety, and a novelty-seeking test to evaluate exploratory behavior and approach-avoidance tendencies. Our results revealed a dichotomy between immediate and delayed finasteride effects. While effects after subchronic treatment were mild, significant behavioral alterations emerged at the withdrawal. In particular, pronounced hyperactivity, decreased center exploration in the open field, and marked avoidance of novel stimuli, collectively indicating an anxiety-like behavioral phenotype, were revealed. These results, showing a picture of increased vulnerability, are in agreement with clinical reports in PFS, highlighting the relevance of our model for this condition. Moreover, the data here described strengthen the importance of monitoring patients not only during treatment but also following discontinuation of finasteride therapy.

Oral finasteride 1 milligram (1 mg) daily-which is a 5-alpha reductase inhibitor (5-ARI) approved by the Food and Drug Administration (FDA) for androgenetic alopecia-is linked to sexual adverse events (AEs). However, it remains unclear whether this link is causal or merely correlational. In FAERS, AEs are described by preferred terms (pts) of the Medical Dictionary for Regulatory Activities system; we investigated 8 AEs, including erectile dysfunction (pt = 10,061,461). We determined if signals could be detected with finasteride 1 mg-and 0.5 mg of dutasteride (a more potent 5-ARI)-in FAERS, for sexual AEs related to the post-finasteride syndrome (PFS): for the two, we identified the yearly number of cases (i.e. reports with sexual AEs) from 2006 to 2024. For each AE, we conducted a disproportionality analysis where reporting odds ratios (RORs) were estimated-along with p-values and 95% confidence intervals (CIs). There were more reports with finasteride 1 mg than with dutasteride 0.5 mg; for both, more reporting was observed as of 2012, the year the PFS foundation formally propagated PFS awareness. Our findings support that the disproportionately higher reporting of sexual AEs with finasteride 1 mg than with dutasteride 0.5 mg-even more so after 2012-could be attributed to the nocebo effect.

The United States Food and Drug Administration (FDA) approved oral finasteride for androgenetic alopecia. In 2022, approximately 2.6 million U.S. men used it for hair loss and prostate conditions. Post-finasteride syndrome (PFS), proposed in 2012, involves persistent sexual and neuropsychiatric adverse events (AEs) after cessation. These AEs are controversial and often lack assessment of contributing risk factors. We analyzed FDA Adverse Event Reporting System (FAERS) data to explore finasteride's administration route and PFS-like AEs. Using the information component (IC) method for disproportionality analyses, we assessed signals for 13 PFS-related AEs with topical and oral finasteride and dutasteride across two periods: 2006-2011 (pre-PFS reporting) and 2019-2024 (post-PFS reporting). These periods reflect times before and after formal PFS reporting in 2012. Eight analyses per AE were conducted based on agent, route, and era. Fewer signals for PFS-like AEs were detected with topical finasteride compared to oral finasteride in both eras. No signals were found for topical dutasteride, possibly because its use is very limited. Many reported AEs, such as erectile dysfunction and depression, may be influenced by age, stress, or comorbidities. Signals for PFS-like AEs were detected with topical finasteride, but were less frequent than with oral finasteride. The high prevalence of these AEs in the general population and the influence of confounding factors, such as psychological stress or nocebo effects, combined with the lack of genotyping, hormonal assessments, or family history data in most reports, suggest caution in attributing causality to finasteride. Topical finasteride may pose a lower risk, but robust evidence is needed to clarify its safety profile.

Finasteride is commonly utilized in clinical practice for treating androgenetic alopecia, but real-world data regarding the long-term safety of its 0adverse events(AEs) remains incomplete, necessitating ongoing supplementation. This study aims to evaluate the AEs associated with finasteride use, based on data from the US Food and Drug Administration Adverse Event Reporting System (FAERS), to contribute to its safety assessment. We reviewed AE reports associated with finasteride from the US Food and Drug Administration Adverse Event Reporting System database, covering the period from the first quarter of 2004 to the first quarter of 2024. We assessed the safety of finasteride medication and AEs using four proportional disproportionality analyses: reported odds ratio (ROR), proportionate reporting ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPN), and Multi-Item Gamma Poisson Shrinkage (MGPS). These methods were used to evaluate whether there is a significant association between finasteride drug use and AEs. To investigate potential safety issues related to drug use, we further analyzed the similarities and differences in the onset time and AEs by sex, as well as the similarities and differences in AEs by age. A total of 11,557 AE reports in which finasteride was the primary suspected drug were analysed. The majority of patients were male (86.04%) and a significant proportion were young adults aged 18-45 years (27.22%). A total of 73 different AEs were categorised into 7 system organ classes (SOCs), with common AEs including erectile dysfunction and sexual dysfunction. In addition, we identified previously unlisted AEs, including Peyronie's disease and post-5α reductase inhibitor syndrome. Of the reported AEs, 102 occurred in men and 7 in women, with depression and anxiety being significant AEs observed in both sexes. When analysed by age group, there were 17 AEs in patients aged ≤ 18 years, 157 in patients aged 18-65 years and 133 in patients aged ≥ 65 years. Common AEs in all age groups included erectile dysfunction, decreased libido, depression, suicidal ideation, psychotic disturbances and attention disorders. The median time to onset of all AEs was 61 days, with the majority occurring within the first month of treatment. Notably, a significant number of AEs persisted beyond one year of treatment. The results of our study uncovered both known and novel AEs associated with finasteride medication. Some of these AEs were identical to the specification, and some of them signaled AEs that were not demonstrated in the specification. In addition, some AEs showed variations based on sex and age in our study. Consequently, our findings offer valuable insights for future research on the safety of finasteride medication and are anticipated to enhance its safe use in clinical practice.

Androgenetic alopecia (AGA) is extremely prevalent with a multifactorial etiology. We conducted a cross-sectional study using the All of US (AoU) dataset Sept 2024 to better understand the epidemiology, social determinants and management of AGA. Most males were 20-39 years old and females 60-69 years old. Men typically have an earlier onset of AGA than females. Male AGA is generally managed with finasteride; oral minoxidil is prescribed in younger males. Females are prescribed spironolactone and oral minoxidil with finasteride in post-menopausal females. There was very little dutasteride prescribed. Topical minoxidil is available over the counter and was not evaluated. Early in 2011 there were reports of the Post-Finasteride Syndrome (PFS); subsequently, the finasteride prescription rate fell to about 10-20% of the pre-PFS prescription rate. There was increased reporting for AGA in those who drink, have an annual household income ≥$75,000, and those with a higher level of education. There was also higher reporting of female AGA in those with anxiety and depression. Patients with higher income and education may have less pressing medical concerns enabling them to bring their AGA to the physician's attention. Females in whom the AGA affects their anxiety and depression may seek help for the AGA as a way to address their underlying disorder. This study provides a snapshot of the epidemiology and management of AGA in the USA. AGA is linked to the social determinants of health; addressing the AGA may help better manage the underlying mental and physical state.