Which of the following is NOT a listed adverse effect of finasteride?

• A. Decreased libido
• B. Erectile dysfunction
• C. Fetal risk
• D. Vision changes

Answer: (D)

Finasteride lowers dihydrotestosterone by inhibiting 5-alpha-reductase. This mechanism explains common adverse effects on sexual function, such as decreased libido and erectile dysfunction, because reduced DHT can impair sexual drive and erectile performance. Fetal risk arises because antiandrogen effects can disrupt male fetal development, so the drug is contraindicated in pregnancy and exposure during pregnancy is avoided. Vision changes, however, are not a standard, listed adverse effect associated with finasteride in typical pharmacology references. Therefore, vision changes are not expected as a known adverse effect, making that option the correct choice.