Sexual adverse experiences such as erectile dysfunction, loss of libido, and ejaculation disorders have been consistent side effects of Finasteride in a maximum percentage of 15% after one year of therapy as reported in the PLESS-Study. Such data could be seen as far from reality, if compared to a higher percentage that may be found in any common clinical practice. This study wishes to explain the dichotomy between literatureʼs data and clinical practice data.

120 patients with diagnosis of Benign Prostatic Hyperplasia (prostate volume >40 ml), age ranging between 45 and 65, sexually active (IIEF questionnairie > 25) in a stable relationship for at least 6 months; testosterone level in the normal range; never on previous BPH medication were randomized to receive finasteride 5 mg per day for one year with (group 2) or without (group 1) counselling 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 “.The estimation of side effect was conducted at 6 months and 12 months with MSF 4 Questionarie and the information reported by patients diary.

Data are referred to 107 patients who completed the study.Group 2 patients (N= 55) reported a significant higher proportion of sexual side effects as compared to group 1 (N °=52) (43.6 vs 15.3%).The incidence of erectile dysfunction; decrease libido.; ejaculation disorders were 9.6%, 7.7%,5.7% for group 1 and 30,9%; 23,6%; 16,3% for group 2 respectively.

In the current study Finasteride showed a significantly higher proportion of sexual dysfunction in patients informed on side effects (group 2) as compared to those in which information on side effects was blinded (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 has access to the drug information sheet. The burden of this nocebo effect has to be taken into account when managing finasteride sexual side effects.