Adverse Effects of Oral Finasteride

Introduction to Adverse Effects

• Approximately 6-7% of finasteride users discontinue treatment due to adverse effects, with sexual side effects occurring in 2-4% more patients compared to placebo, though overall discontinuation rates are similar between finasteride and placebo at approximately 15% 1, 2

Endocrine and Discontinuation Effects

• Across all RCTs, finasteride shows a 2-4% absolute increase in gynecomastia compared to placebo 1, 2
• The combined discontinuation rate specifically due to adverse events is approximately 6-7% for both finasteride and placebo groups 1, 2
• The overall discontinuation rate for any reason is approximately 15% in both finasteride and placebo arms 1, 2

Important Clinical Context

• The clinical significance of sexual side effects must be contextualized: on a 0-100 scale measuring sexual dysfunction, finasteride caused a mean difference of only 3.21 points, compared to 1.26 points for each additional year of age 1, 2