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Finasteride

Generic Name: finasteride (fin AS ter ide)
Brand Name: Propecia, Proscar

Medically reviewed on Jul 20, 2018

What is finasteride?

Finasteride prevents the conversion of testosterone to dihydrotestosterone (DHT) in the body. DHT is involved in the development of benign prostatic hyperplasia (BPH).

Finasteride is used to treat male pattern hair loss in men. It is also used to treat symptoms of benign prostatic hyperplasia (BPH) in men with an enlarged prostate.

finasteride is for use in men only.

Finasteride may also be used for purposes not listed in this medication guide.

Important Information

Finasteride should never be taken by a woman or a child.

Finasteride can cause birth defects if a woman is exposed to it during pregnancy. Finasteride tablets should not be handled by a woman who is pregnant or may become pregnant.

Before taking this medicine

You should not use finasteride if you are allergic to it.

finasteride should never be taken by a woman or a child. Finasteride can be absorbed through the skin, and women or children should not be permitted to handle finasteride tablets.

Using finasteride may increase your risk of developing prostate cancer. Talk with your doctor if you have concerns about this risk.

Tell your doctor if you have ever had:

Although finasteride is not for use by women, this medicine can cause birth defects if a woman is exposed to it during pregnancy. Finasteride tablets should not be handled by a woman who is pregnant or who may become pregnant.

If a woman accidentally comes into contact with a broken or crushed tablet, wash the area with soap and water right away.

How should I take finasteride?

Your doctor will perform blood tests to make sure you do not have conditions that would prevent you from safely using finasteride.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Take this medicine with a full glass of water.

Take the medicine at the same time each day, with or without food.

Use finasteride regularly to get the most benefit.

It may take up to 3 months or longer before you receive the full benefit of taking finasteride. Your doctor will determine how long to treat you with this medicine. Keep using the medication as directed.

You will need frequent medical tests. Your doctor will also test your prostate specific antigen (PSA) to check for prostate cancer.

Store at room temperature away from moisture, heat, and light. Keep the bottle tightly closed when not in use.

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Get your prescription refilled before you run out of medicine completely.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking finasteride?

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.

Finasteride side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you notice any signs of male breast cancer, such as:

Common side effects may include:

  • loss of interest in sex;

  • impotence;

  • trouble having an orgasm; or

  • abnormal ejaculation.

The sexual side effects of finasteride may continue after you stop taking finasteride. Talk to your doctor if you have concerns about these side effects.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

Finasteride dosing information

Usual Adult Dose for Benign Prostatic Hyperplasia:

5 mg orally once a day

Comments:
-Dosing is the same both in monotherapy and in combination therapy.

Usual Adult Dose for Androgenetic Alopecia:

1 mg orally once a day

For the treatment of male pattern hair loss (androgenetic alopecia) in men only. (Safety and efficacy have been demonstrated in men between 18 to 41 years of age with mild to moderate hair loss of the vertex and anterior mid scalp area):

Comments:
-Daily use for 3 months or more is necessary before benefit is observed. Continued use is recommended to sustain benefit.
-Withdrawal of treatment leads to reversal of effect within 12 months.

Use: For the treatment of male pattern hair loss (androgenetic alopecia) in men only. (Safety and efficacy have been demonstrated in men between 18 to 41 years of age with mild to moderate hair loss of the vertex and anterior mid scalp area).

What other drugs will affect finasteride?

Other drugs may affect finasteride, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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