title: Finasteride 5 mg and sexual side effects: how many of these are related to a nocebo phenomenon?
abstract: BACKGROUND
  Sexual adverse experiences such as erectile dysfunction (ED), loss of libido, and ejaculation disorders have been consistent side effects of finasteride in a maximum percentage of 15% after 1 year of therapy. Such data could be seen as far from reality, if compared to a higher percentage that may be found in any common clinical practice.
  
  
  OBJECTIVE
  This study aims to explain the dichotomy between literature's data and clinical practice data.
  
  
  METHODS
  One hundred twenty patients with a clinical diagnosis of benign prostatic hyperplasia (BPH), sexually active and with an International Index of Erectile Function-erectile function (IIEF-EF) domain >/=25 were randomized to receive finasteride 5 mg concealed as an "X compound of proven efficacy for the treatment of BPH" for 1 year with (group 2) or without (group 1) counseling on the drug sexual side effect. The phrase used to inform group 2 patients was ". . . it may cause erectile dysfunction, decreased libido, problems of ejaculation but these are uncommon".
  
  
  METHODS
  The estimation of side effect was conducted at 6 and 12 months using the male sexual function-4 (MSF-4 item) questionnaire and a self-administered questionnaire.
  
  
  RESULTS
  One hundred seven patients completed the study. Group 2 patients (N = 55) reported a significant higher proportion of one or more sexual side effects as compared to group 1 (N = 52) (43.6% vs. 15.3%) (P = 0.03). The incidence of ED, decreased libido, and ejaculation disorders were 9.6, 7.7, and 5.7% for group 1, and 30.9, 23.6, and 16.3% for group 2, respectively (P = 0.02, P = 0.04, and P = 0.06).
  
  
  CONCLUSIONS
  In the current study, blinded administration of finasteride was associated with a significantly higher proportion of sexual dysfunction in patients informed on sexual side effects (group 2) as compared to those in which the same information was omitted (group 1) (P = 0.03). A scenario similar to group 2 of the current study is likely to occur in clinical practice, where the patient is counseled by the physician and has access to the drug information sheet. The burden of this nocebo effect (an adverse side effect that is not a direct result of the specific pharmacological action of the drug) has to be taken into account when managing finasteride sexual side effects.
authors.affiliation: UO Urology, S Maria Annunziata Hospital, University of Florence, Florence, Italy. nicola.mondaini@unifi.it
authors.forename: Nicola
authors.initials: N
authors.lastname: Mondaini
authors.forename: Paolo
authors.initials: P
authors.lastname: Gontero
authors.forename: Gianluca
authors.initials: G
authors.lastname: Giubilei
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lombardi
authors.forename: Tommaso
authors.initials: T
authors.lastname: Cai
authors.forename: Andrea
authors.initials: A
authors.lastname: Gavazzi
authors.forename: Riccardo
authors.initials: R
authors.lastname: Bartoletti
mesh_terms: D000368:Aged; D004311:Double-Blind Method; D004791:Enzyme Inhibitors / Q000008:administration & dosage*; D007172:Erectile Dysfunction / Q000139:chemically induced* / Q000517:prevention & control; D018120:Finasteride / Q000008:administration & dosage*; D005500:Follow-Up Studies; D006801:Humans; D007989:Libido / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009948:Orgasm / Q000187:drug effects; D011470:Prostatic Hyperplasia / Q000188:drug therapy*; D012725:Sexual Behavior; D020018:Sexual Dysfunctions, Psychological / Q000139:chemically induced* / Q000517:prevention & control; D011795:Surveys and Questionnaires
chemical_list: D004791:Enzyme Inhibitors; D018120:Finasteride