Generic Name: finasteride (fih NAH steh ride)
Brand Name: Propecia, Proscar
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.
This medicine is for use in men only.
Finasteride may also be used for purposes not listed in this medication guide.
What is the most important information I should know about finasteride?
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.
What should I discuss with my healthcare provider before taking finasteride?
You should not use finasteride if you are allergic to it.
This medicine 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.
To make sure finasteride is safe for you, tell your doctor if you have:
liver disease, or abnormal liver enzyme tests;
a bladder muscle disorder;
stricture of your urethra;
if you are unable to urinate; or
if you have ever had an allergic reaction to a similar medicine called dutasteride (Avodart).
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. Do not take this medicine in larger or smaller amounts or for longer than recommended.
Take this medicine with a full glass of water.
Finasteride can be taken with or without food. Take the medicine at the same time each day.
Use finasteride regularly to get the most benefit. Get your prescription refilled before you run out of medicine completely.
It may take up to 3 months or longer before your symptoms improve. Keep using the medication as directed and tell your doctor if your symptoms do not improve.
While using finasteride, you may need frequent blood 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 missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
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. Get up slowly and steady yourself to prevent a fall.
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:
breast pain or tenderness;
nipple discharge; or
any other breast changes.
Common side effects may include:
loss of interest in sex;
trouble having an orgasm; or
The sexual side effects of finasteride may continue after you stop taking this medicine. 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)
What other drugs will affect finasteride?
Other drugs may interact with finasteride, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.
More about Proscar (finasteride)
- Other brands: Propecia
Related treatment guides
Where can I get more information?
- Your pharmacist can provide more information about finasteride.
- 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.
- Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.
Copyright 1996-2012 Cerner Multum, Inc. Version: 8.01.
Date modified: November 30, 2016
Last reviewed: April 24, 2015