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Finasteride oral tablet side effects: A detailed guide

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More common side effectsMild side effectsSerious side effectsFAQsCouponSide effects in detailWarningsAsk your doctor
Finasteride oral tablet is prescribed to adults for treating benign prostatic hyperplasia (BPH) and hair loss. It’s a 5-alpha reductase inhibitor drug that may cause mild or serious side effects, including low sex drive and abnormal breast growth.
Medically reviewed by Amber R. Watson, PharmD
Updated on

Specifically, the Food and Drug Administration (FDA) has approved finasteride oral tablet to treat the following in adults:

This article describes possible side effects of finasteride oral tablet. You’ll also find information on cost savings and coupon options for finasteride.

Finasteride oral tablet is a generic version of the brand-name drugs Propecia and Proscar.

You can explore this overview article to learn more about finasteride oral tablet, including the drug’s uses, dosage, ways to save on cost, and more.

* Sex and gender exist on spectrums. In this article, we use the term “male” to refer to a person’s sex assigned at birth.

More common side effects of finasteride

Finasteride oral tablet may cause mild or serious side effects. Below are some of the more common side effects of this medication.

Commonly reported side effects of finasteride oral tablet when used to treat benign prostatic hyperplasia (BPH) include:

Commonly reported side effects of finasteride oral tablet when used to treat male pattern hair loss† include:

* To learn more about this side effect, see the “Side effects of finasteride in detail” section below.
Sex and gender exist on spectrums. In this article, we use the term “male” to refer to a person’s sex assigned at birth.

Mild side effects of finasteride

Finasteride may cause certain mild side effects. Most often, mild side effects are temporary and can be easily managed. Tell your doctor or pharmacist if you have side effects that don’t go away or become bothersome.

Mild side effects of finasteride oral tablet that occurred in studies for benign prostatic hyperplasia (BPH) and studies for male pattern hair loss† include:

* To learn more about this side effect, see the “Side effects of finasteride in detail” section below.
Sex and gender exist on spectrums. In this article, we use the term “male” to refer to a person’s sex assigned at birth.
‡ An allergic reaction is possible with finasteride oral tablet. It’s unclear whether it occurred in the drug’s studies for BPH or studies for male pattern hair loss. But allergic reactions have happened since finasteride oral tablet was approved for treating these conditions.

Finasteride oral tablet may cause more mild side effects than those listed above. For details, see the drug’s prescribing information for BPH and prescribing information for male pattern hair loss.

Serious side effects of finasteride

Finasteride may cause certain serious side effects. If you have any serious side effects from finasteride oral tablet, call your doctor right away. But if you think you’re having a medical emergency or your side effects feel life threatening, take immediate action. Call 911, or a local emergency number, or go to the nearest emergency room.

After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Visit MedWatch’s website if you’d like to notify the FDA about a side effect you’ve had with finasteride oral tablet.

Serious side effects of finasteride oral tablet that occurred in studies for benign prostate hyperplasia (BPH) include:

No serious side effects were reported in studies of finasteride oral tablet for male pattern hair loss.‡

* To learn more about this side effect, see the “Side effects of finasteride in detail” section below.
† An allergic reaction is possible with finasteride oral tablet. It’s unclear whether it occurred in the drug’s studies, but it has happened since the drug was approved for use.
Sex and gender exist on spectrums. In this article, we use the term “male” to refer to a person’s sex assigned at birth.

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Common questions about side effects of finasteride

Here are answers to some common questions about side effects of finasteride oral tablet. If you have other questions, talk with your doctor or pharmacist.

Are side effects of finasteride different when prescribed for male pattern hair loss vs. benign prostatic hyperplasia?

No, for the most part, they’re not different.

Side effects were nearly identical in studies of finasteride for male pattern hair loss* and in studies for benign prostatic hyperplasia (BPH). Exceptions include low blood pressure when standing or sitting up and an increased risk of prostate cancer. These side effects were reported in the BPH studies but not in the hair loss studies.

Enlarged breasts and tender breasts are also possible exceptions. These side effects occurred in both studies, but:

  • In the hair loss studies, these side effects were as likely in people taking 1 milligram (mg) of finasteride daily and people taking a placebo. (A placebo is a treatment with no active drug.)
  • In the BPH studies, these side effects were more common in people taking 5 mg of finasteride daily than in people taking a placebo.

Talk with your doctor or pharmacist to learn more about your risk of side effects from finasteride.

* Sex and gender exist on spectrums. In this article, we use the term “male” to refer to a person’s sex assigned at birth.

Will finasteride 1 mg cause fewer side effects than finasteride 5 mg?

It’s possible. Usually, lower strengths of a drug are less likely to cause side effects than higher strengths. But in studies of finasteride 1 mg and finasteride 5 mg, rates of side effects were the same or very similar.

Talk with your doctor or pharmacist to learn more about your risk of side effects based on the finasteride dose prescribed for you.

Does finasteride cause long-term side effects?

Yes, in some cases, finasteride oral tablet may cause long-term side effects. These can occur if you take the drug for a long time.

Examples of long-term side effects include:

  • Low blood pressure when standing or sitting up, which could result in fainting and falls. This risk is possible during treatment with finasteride, but it goes away once you stop taking the drug.
  • Risk of prostate cancer.* This risk is possible during treatment. This side effect may continue to cause long-term effects even after you stop taking the drug.
  • Sexual side effects, including erectile dysfunction*and low sex drive.* These risks are possible during treatment. They may go away if you continue taking finasteride for more than 1 year. And they should go away once you stop taking the drug.

* To learn more about this side effect, see the “Side effects of finasteride in detail” section below.

Talk with your doctor to learn more about these side effects and how to best manage them. Ask your doctor for more information about how long these side effects of finasteride may last.

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Side effects of finasteride in detail

Below you’ll find details on some of the side effects of finasteride oral tablet.

Erectile dysfunction

Erectile dysfunction (ED) was a somewhat common side effect in finasteride’s studies. It was reported in studies for male pattern hair loss* and in studies for benign prostatic hyperplasia (BPH). With ED, you’re unable to maintain or have an erection firm enough for sex.

This side effect is usually mild. And it may go away as you continue taking finasteride.

It’s important to point out that BPH can also cause ED. (Finasteride may be prescribed to treat BPH.)

* Sex and gender exist on spectrums. In this article, we use the term “male” to refer to a person’s sex assigned at birth.

Ways to manage

If you have symptoms of ED, tell your doctor. They’ll likely recommend one of more of the following options:

  • continuing treatment with finasteride and finding out whether this side effect goes away
  • trying a medication to treat ED, if there is a drug that’s safe for you to take
  • stopping treatment with finasteride and exploring other treatments for your condition

Low sex drive

Low sex drive also was a somewhat common side effect in finasteride’s studies. It was reported in studies for male pattern hair loss* and in studies for benign prostatic hyperplasia (BPH). This side effect is usually mild.

With low sex drive, you have a decreased interest in sex. It’s normal for your sex drive to rise and fall or not to match your partner’s. But having low sex drive for a long time is concerning for some people. It can also be a sign of another health condition, such as low testosterone or depression.

* Sex and gender exist on spectrums. In this article, we use the term “male” to refer to a person’s sex assigned at birth.

Ways to manage

If you experience low sex drive, tell your doctor. Options they may recommend include:

  • continuing treatment with finasteride and finding out whether this side effect goes away
  • exploring treatment for low sex drive, such as cognitive behavioral therapy (CBT)
  • stopping treatment with finasteride and exploring other treatments for your condition

Prostate cancer

An increased risk of prostate cancer was rare in studies of finasteride oral tablet for benign prostatic hyperplasia (BPH). This side effect may be serious. An increased risk of prostate cancer was not reported in studies of finasteride for male pattern hair loss.*

Prostate cancer happens when a tumor develops in the prostate. The prostate is a small gland in males that produces semen.

Symptoms of prostate cancer include:

  • frequent need to urinate
  • erectile dysfunction
  • numbness or weakness in your legs or feet
  • slow or weak urine stream

*Sex and gender exist on spectrums. In this article, we use the term “male” to refer to a person’s sex assigned at birth.

Ways to manage

If you have symptoms of or concerns about prostate cancer, tell your doctor. They’ll likely recommend:

  • coming in for an appointment if you’re concerned about possible symptoms
  • discussing ways to screen for prostate cancer if you’re concerned about this risk in general

Allergic reaction

For some people, finasteride oral tablet can cause an allergic reaction. It’s unclear whether this side effect occurred in the drug’s studies for benign prostatic hyperplasia (BPH) or studies for male pattern hair loss.* But allergic reactions have happened since finasteride oral tablet was approved for these conditions.

Symptoms can be mild or serious, and they may include:

  • itchiness
  • skin rash
  • swelling under the skin, usually affecting eyelids, lips, hands, or feet
  • swelling of the mouth, tongue, or throat, which can make it hard to breathe
  • flushing (temporary warmth, redness, or deepening of skin color)

*Sex and gender exist on spectrums. In this article, we use the term “male” to refer to a person’s sex assigned at birth.

Ways to manage

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.

For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to finasteride oral tablet, your doctor may recommend taking a different medication instead.

Warnings for finasteride

Below are some factors you may want to discuss with your doctor before taking finasteride oral tablet.

Warnings

It may not be safe for you to take finasteride oral tablet if you have specific health conditions. These are sometimes called drug-condition interactions. Other things may also affect whether finasteride oral tablet is a safe treatment option for you.

Before taking finasteride oral tablet, tell your doctor about your health and medications you take. Things to consider include:

Finasteride and pregnancy

Finasteride oral tablet should not be taken during pregnancy.

Finasteride is approved only for use in males.* It’s not approved for any use in females.*

Keep in mind that pregnant people should not touch finasteride oral tablets that are crushed or broken. But it should be safe to touch finasteride oral tablets that are not crushed or broken. If you’re pregnant and have contact with a crushed or broken finasteride tablet, wash the area with soap right away.

*Sex and gender exist on spectrums. In this article, we use the terms “male” and “female” to refer to a person’s sex assigned at birth.

Finasteride and breastfeeding

It’s not known whether finasteride oral tablet should be taken while breastfeeding.

Finasteride is approved only for use in males.* It’s not approved for any use in females.*

*Sex and gender exist on spectrums. In this article, we use the terms “male” and “female” to refer to a person’s sex assigned at birth.

Finasteride and alcohol

Finasteride oral tablet is not known to interact with alcohol.

If you drink alcohol, talk with your doctor about whether it’s safe to consume it during your treatment with finasteride oral tablet.

What to ask your doctor

This article describes common and serious side effects of finasteride oral tablet. If your doctor prescribes this medication, they can discuss possible side effects with you. Let your doctor know if you have concerns or questions about treatment with this medication.

Here’s a list of some possible questions you may want to ask your doctor:

  • If I’m taking finasteride for benign prostatic hyperplasia (BPH) and have sexual side effects, how can we tell if they are caused by the drug or by my condition?
  • Does my health history increase my risk of side effects from taking finasteride?
  • Do other medications I take increase my risk of side effects if I take finasteride?
  • Will breast growth caused by finasteride go away if I stop taking the medication?

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

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