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Finasteride

Common Brand Names: Proscar, Propecia

Side Effects & Precautions

Medically reviewed by Jessica Swirble, PharmD
Last updated on 4/20/2024

Drug Information | Side Effects | Use & Dosage | Request a Prescription

What are the side effects of finasteride?

The use of finasteride can lead to various side effects in some individuals.

Common mild side effects of finasteride use include:

  • Erectile dysfunction
  • Decreased libido (sex drive)
  • Ejaculation disorders (such as decreased semen volume)

More severe side effects of finasteride use can include:

  • Allergic reactions (rash, itching, swelling of the face or lips, difficulty breathing)
  • Breast tenderness or enlargement
  • Depression or mood changes
  • Testicular pain or swelling
  • Breast lumps or nipple discharge
  • Painful erections or other sexual dysfunction

Finasteride may increase your risk of developing prostate cancer or breast cancer. Discuss these risks with your healthcare provider before starting treatment with finasteride.

If you experience any severe side effects while taking finasteride, contact your healthcare provider immediately.

What should I tell my healthcare provider before using finasteride?

Inform your healthcare provider about any existing medical conditions, allergies, or other medications you are taking before starting treatment with finasteride. This includes prescription drugs, over-the-counter medications, and dietary supplements, as they may interact with finasteride.

Tell your provider if you are taking these medications or supplements:

  • Alpha-blockers (used to treat high blood pressure and prostate conditions)
  • Medications that affect male hormones (androgens)
  • Herbal supplements or vitamins (especially St. John’s wort)

Mention medical conditions such as:

  • Liver disease or abnormal liver function tests
  • Prostate cancer or other prostate issues
  • Allergic reactions to medications

If you are pregnant, planning to become pregnant, or breastfeeding, avoid handling crushed or broken finasteride tablets due to the risk of absorption through the skin, which may harm the unborn baby or nursing infant.

Are there any other special instructions I should follow?

Take finasteride exactly as prescribed by your healthcare provider. Do not increase or decrease the dosage without consulting them.

Finasteride may take several months to show noticeable effects, especially for male pattern baldness. Continuously taking the medication as directed is important for achieving and maintaining results.

What should I do in case of an overdose?

In case of a finasteride overdose, seek medical attention immediately. Symptoms of overdose may include dizziness, seizures, lightheadedness, fainting, or trouble breathing. If you suspect an overdose, contact the poison control helpline at 1-800-222-1222 or call emergency services.