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Finasteride

(fi nas' teer ide)

Brand Name(s): Propecia®, Proscar®; also available generically

WHY is this medicine prescribed?

Finasteride (Proscar) is used alone or in combination with another medication (doxazosin [Cardura]) to treat benign prostatic hypertrophy (BPH, enlargement of the prostate gland). Finasteride is used to treat symptoms of BPH such as frequent and difficult urination and may reduce the chance of acute urinary retention (sudden inability to urinate). It also may decrease the chance that prostate surgery will be needed. Finasteride (Propecia) is also used to treat male pattern hair loss (gradual thinning of the hair on the scalp, leading to a receding hairline or balding on the top of the head in men.) Finasteride (Propecia) has not been shown to treat thinning hair at the temples and is not used to treat hair loss in women or children. Finasteride is in a class of medications called 5-alpha reductase inhibitors. Finasteride treats BPH by blocking the body's production of a male hormone that causes the prostate to enlarge. Finasteride treats male pattern hair loss by blocking the body's production of a male hormone in the scalp that stops hair growth.

Are there OTHER USES for this medicine?

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

HOW should this medicine be used?

Finasteride comes as a tablet to take by mouth. It is usually taken once a day with or without food. Take finasteride at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take finasteride exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

If you are taking finasteride to treat BPH, you should know that finasteride may control your condition, but will not cure it. It may take at least 6 months before your symptoms improve. Continue to take finasteride even if you feel well. Do not stop taking finasteride without talking to your doctor.

If you are taking finasteride to treat male pattern hair loss, it may take at least 3 months before you see any improvement because hair loss and growth happen slowly over time. However, you should expect to see improvement during the first 12 months of your treatment. If you have taken finasteride for 12 months and have not noticed any improvement, further treatment probably will not help. Talk to your doctor about whether you should continue your treatment.

Finasteride will only slow hair loss while you are taking the medication. Continue to take finasteride even if you have already noticed an improvement. Do not stop taking finasteride without talking to your doctor. You will probably lose any hair that grew back while you were taking finasteride during the first 12 months after you stop taking the medication..

Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.

What SPECIAL PRECAUTIONS should I follow?

Before taking finasteride,

  • tell your doctor and pharmacist if you are allergic to finasteride, any other medications, or any of the ingredients in finasteride tablets. Ask your pharmacist or check the patient information for a list of the ingredients.
  • tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • tell your doctor if you have or have ever had liver disease or prostate cancer.
  • you should know that finasteride is only for use in men. Women, especially those who are or may become pregnant should not touch broken or crushed finasteride tablets. Touching broken or crushed finasteride tablets may harm the fetus. If a woman who is pregnant or who could become pregnant touches broken or crushed finasteride tablets, she should wash the area with soap and water immediately and call her doctor.

What should I do IF I FORGET to take a dose?

Skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What SIDE EFFECTS can this medicine cause?

Finasteride may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • inability to have or maintain an erection
  • decreased sexual desire
  • problems with ejaculation (including decreased volume of ejaculate)
  • pain in the testicles
  • depression

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

  • changes in the breasts such as increased size, lumps, pain, or nipple discharge
  • rash
  • itching
  • hives
  • swelling of the lips and face
  • difficulty breathing or swallowing

Finasteride may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

Taking finasteride may increase the risk that you will develop high-grade prostate cancer (a type of prostate cancer that spreads and grows more quickly than other types of prostate cancer). Talk to your doctor about the risks of taking finasteride.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

What should I do in case of OVERDOSE?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

What OTHER INFORMATION should I know?

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to finasteride.

Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking finasteride.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.


This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists® represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists® makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists® does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

Pronunciation Guide for Drug Names is used with permission. © 2009. The United States Pharmacopeial Convention. All Rights Reserved.

AHFS® Patient Medication Information™. © Copyright, 2020. The American Society of Health-System Pharmacists®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: January 15, 2018.