finasteride treatment from Ro
finasteride treatment from Ro

Important Safety Information for Finasteride

What is the FDA-approved use of finasteride?

Finasteride is a 5α-reductase inhibitor indicated for the treatment of male pattern hair loss (androgenetic alopecia) in men only. 

It is not for use in women.

Who should not use finasteride?

Do not use finasteride if:

  • You are a woman, you are pregnant, or you are trying to become pregnant. Women should not take finasteride or handle crushed or broken finasteride tablets. In animal studies, finasteride caused abnormal development of genitalia in male fetuses.

  • You have a known allergic reaction to finasteride.

How should I take finasteride?

You can take finasteride with or without food. 

In general, daily use for three months or more is necessary before improvement in hair loss is seen. If you’re not seeing a difference after three months, or you have any questions about changing or stopping the medication, reach out to your Ro-affiliated provider for guidance.

What should I tell my Ro-affiliated provider before taking finasteride?
  • It’s important to tell your Ro-affiliated provider all of the medications you are currently taking, including prescription, over-the-counter medications, vitamins, and herbal and dietary supplements. 

  • It’s important to share your entire medical history with your provider. In particular, tell your provider if you have a past history of:

    • Prostate cancer

    • Depression

    • Suicidal thoughts or behavior

Withholding or providing inaccurate information about your health and medical history in order to obtain treatment may result in harm, including, in some cases, death.

What are the most serious side effects that I or a caregiver should monitor for when taking finasteride?

If you are experiencing a medical emergency, call 911 or seek immediate medical attention.

  • Effects on Prostate-Specific Antigen (PSA) levels: Finasteride can decrease PSA levels. When checking PSA levels, let your provider know that you are taking finasteride for an accurate interpretation of the results. A PSA test is used as a screening tool for prostate cancer.

  • Increased Risk of High-Grade Prostate Cancer with 5α-Reductase Inhibitors: In two studies studying 5α-reductase inhibitors for the prevention of prostate cancer, an increase in high-grade prostate cancer was found.

What are the most common side effects of finasteride?
  • Decreased libido

  • Erectile dysfunction

  • Ejaculation disorder

You are encouraged to report negative side effects of prescription products to the FDA. Visit or call 1-800-FDA-1088.

This information is not comprehensive. Please see the full Prescribing Information for complete safety information.