Finasteride (Oral Route)

Drug Information provided by: Micromedex

ARTICLE SECTIONS

US Brand Names

Propecia
Proscar

Description

Note: Women of childbearing potential should not use or handle crushed finasteride tablets. Finasteride can cause birth defects in male fetuses.

Finasteride belongs to the group of medicines called enzyme inhibitors. It is used to treat urinary problems caused by enlargement of the prostate (benign prostatic hyperplasia or BPH). In men with very enlarged prostates and mild to moderate symptoms (difficulty urinating, decreased flow of urination, hesitation at the beginning of urination, getting up at night to urinate), finasteride may decrease the severity of symptoms. Finasteride may also reduce the chance that surgery on the prostate will be needed.

Finasteride blocks an enzyme called 5-alpha-reductase, which is necessary to change testosterone to another hormone that causes the prostate to grow. As a result, the size of the prostate is decreased. The effect of finasteride on the prostate lasts only as long as the medicine is taken. If it is stopped, the prostate begins to grow again.

Finasteride also is used by some balding men to stimulate hair growth. If hair growth is going to occur with the use of finasteride, it usually occurs after the medicine has been used for about 3 months and lasts only as long as the medicine continues to be used. The new hair will be lost within 1 year after finasteride treatment is stopped.

Finasteride is available only with your doctor's prescription.

This product is available in the following dosage forms:

Tablet

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Geriatric

This medicine has been tested and has not been shown to cause different side effects or problems in older people than it does in younger adults.

Pregnancy

	Pregnancy Category	Explanation
All Trimesters	X	Studies in animals or pregnant women have demonstrated positive evidence of fetal abnormalities. This drug should not be used in women who are or may become pregnant because the risk clearly outweighs any possible benefit.

Breastfeeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Proper Use

Finasteride tablets may be crushed to make them easier to swallow. However, women who are or may become pregnant should not handle crushed finasteride tablets.

For patients taking this medicine for benign prostatic hyperplasia (BPH):

To help you remember to take your medicine, try to get into the habit of taking it at the same time each day.
Remember that this medicine does not cure BPH but it does help reduce the size of the prostate. Therefore, you must continue to take it if you expect to keep the size of your prostate down. You may have to take this medicine for at least 6 months to see the full effect. You may have to take this medicine for the rest of your life. Do not stop taking this medicine without first discussing it with your doctor.
This medicine helps to reduce urinary problems in men with BPH. In general, it is best to avoid drinking fluids, especially coffee or alcohol, in the evening. Then your sleep will not be disturbed by your need to urinate during the night.

For individuals taking this medicine for hair growth:

You may have to take this medicine for at least 3 months to see an effect. The effect will last only as long as the medicine continues to be used. The new hair will be lost within 1 year after finasteride is stopped.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

For oral dosage form (tablets):
- For treatment of benign prostatic hyperplasia (BPH):
  - Adults—5 milligrams (mg) once a day.
- For hair growth:
  - Adults—1 mg once a day.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Precautions

Women who are or who may become pregnant should not handle crushed finasteride tablets. There is a risk that the medicine could get into the pregnant woman's body and cause birth defects in a male fetus.

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

Less common

Breast enlargement and tenderness
Skin rash
Swelling of lips

Note: Breast enlargement and tenderness, skin rash and swelling of lips are more likely to occur with the 5-mg dose.

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common or rare