Introduction: Recent studies have reported persistent sexual and nonsexual adverse effects associated with the 5α-reductase inhibitor finasteride.
Aims: The first aim was to review the clinical studies of persistent sexual and nonsexual adverse effects associated with finasteride in younger men who took the medication for treatment of male pattern hair loss. The second aim was to place these findings into context with what is known from basic and clinical studies about the hormones and neurosteroids affected by finasteride.
Methods: Relevant published literature on the topic was reviewed. Clinical symptomatology in humans was correlated with findings from rodent models to investigate possible underlying mechanisms.
Main outcome measures: Persistent sexual and nonsexual adverse effects were summarized.
Results: Two clinical studies have described persistent side effects associated with finasteride use in otherwise healthy younger men. The sexual side effects are typically present in multiple domains that include erectile dysfunction, low libido, and decreased orgasms. Erectile dysfunction may be related to low levels of dihydrotestosterone, which has been shown to be an important androgen in both human and animal studies. Nonsexual side effects include depression and decreased alcohol consumption that are linked to the neurosteroid allopregnanolone in both human and animal studies. Three men with persistent side effects associated with finasteride were found to have lower plasma and cerebrospinal fluid levels of several neurosteroids.
Conclusions: Persistent adverse effects of finasteride in younger men include erectile dysfunction, low libido, lack of orgasms, depression, and decreased alcohol consumption. One study has found lower levels of several neurosteroids in this population. Out of the various persistent side effects, erectile dysfunction and decreased alcohol consumption have been the most studied in animal models. Further research is needed on who is susceptible to the persistent adverse side effects of finasteride and on the underlying mechanisms of the medication. Irwig MS. Persistent sexual and non-sexual adverse effects of finasteride in younger men. Sex Med Rev 2014;2:24-35.
Keywords: Depression; Erectile Dysfunction; Finasteride; Neurosteroids; Propecia; Side Effects.
Copyright © 2014 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.