Avodart

Introduction

Written by Helen Marshall, BPharm, MRPharmS
Medically reviewed by Melissa Badowski, PharmD, MPH, FCCP
Updated on July 28, 2023

Dutasteride (doo TAS teer ide) is a generic medication prescribed for an enlarged prostate. Dutasteride belongs to a group of drugs called 5-alpha-reductase inhibitors.

Side effects of dutasteride

Dutasteride may cause mild or serious side effects. More common mild side effects of dutasteride and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.

To learn more about dutasteride’s side effects, ask your doctor or pharmacist. You can also refer to the prescribing information for dutasteride listed in the “Resources” section.

Mild side effects

More common mild side effects reported with dutasteride are listed below.

This article doesn’t include all possible mild side effects of the drug. To learn more about dutasteride’s side effects, refer to the prescribing information for dutasteride listed in the “Resources” section.

With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects bother you, tell your doctor or pharmacist. They may be able to suggest ways to manage them.

Dutasteride oral capsule’s mild side effects include:

• erectile dysfunction (trouble getting or keeping an erection)
• reduced sex drive
• ejaculation problems
• tender or enlarged breasts
• mild allergic reaction*

* For details about this side effect, see the “Interactions and warnings for dutasteride” section.

Serious side effects

Serious side effects of dutasteride are listed below.

This article doesn’t include all possible serious side effects of the drug. To learn more about dutasteride’s side effects, refer to the prescribing information for dutasteride listed in the “Resources” section.

With many drugs, serious side effects are possible but not common. If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.

In general, dutasteride’s serious side effects include:

• increased risk of a serious form of prostate cancer
• severe allergic reaction*

* For details about this side effect, see the “Interactions and warnings for dutasteride” section.

Common questions about dutasteride

Below you’ll find answers to a few commonly asked questions about dutasteride.

How does dutasteride compare with finasteride?

Like dutasteride, finasteride (Proscar) treats an enlarged prostate. They’re very similar medications. Both belong to a group of drugs called 5-alpha-reductase inhibitors. They’re both taken once a day and can cause similar side effects.

The Food and Drug Administration (FDA) has also approved finasteride for treating male-pattern baldness.* Doctors sometimes prescribe dutasteride off-label for this use as well. (Off-label use is when a drug is prescribed to treat a condition other than its approved uses.)

To learn more about how dutasteride compares with finasteride, talk with your doctor. They can help you determine if one of these medications is a better choice for you.

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

Is it safe to take dutasteride along with tamsulosin?

Yes, it’s safe to take dutasteride with tamsulosin (Flomax). In fact, doctors commonly prescribe these medications together to treat an enlarged prostate.

You may be more likely to have certain side effects if you take these medications together. These include ejaculation problems, erectile dysfunction (trouble getting or keeping an erection), reduced sex drive, enlarged or tender breasts, and dizziness. But most people take the combination without having any problems.

If you’re concerned about taking dutasteride with tamsulosin, talk with your doctor.

When is the best time of day to take dutasteride?

There’s no best time of day to take dutasteride. You can take your daily dose at a time that best suits you, but try to stick to around the same time each day. This keeps a steady level of the medication in your body, which helps it work effectively.

How does dutasteride work? And how long does it take to start working?

Dutasteride treats an enlarged prostate by shrinking your prostate. It works by blocking the action of an enzyme (a type of protein) called 5-alpha-reductase. This enzyme usually helps make a hormone called dihydrotestosterone (DHT) that encourages your prostate to grow.

By stopping your body from making DHT, dutasteride stops your prostate from growing and makes it shrink. This stops your prostate from pressing on your bladder and urethra, which reduces symptoms such as trouble urinating.

Dutasteride starts working as soon as you start taking it. But it may take a couple of weeks before your DHT levels decrease. It may take 3–6 months before you feel relief from your symptoms.

If you’d like to know more about this, talk with your doctor or pharmacist.

Uses of dutasteride

The Food and Drug Administration (FDA) approves prescription drugs such as dutasteride for certain conditions. Approved uses for dutasteride are described below.

Use for enlarged prostate

Doctors may prescribe dutasteride oral capsule for treating benign prostatic hyperplasia (BPH), which is also known as an enlarged prostate. It’s used for this purpose in adult males.* Doctors usually prescribe it as a long-term treatment.

With BPH, your prostate gets bigger. This is not prostate cancer. But the enlarged prostate presses on your bladder and urethra and can affect the way you urinate. For example, you may have trouble urinating, produce a weak flow of urine, or cannot fully empty your bladder. You may also need to urinate more often, especially at night, and have sudden urges to urinate.

Dutasteride is a medication that shrinks your enlarged prostate. It helps reduce the urinary symptoms of BPH. It also lowers your risk of acute urinary retention (being unable to empty your bladder). Dutasteride can also lower your risk of needing surgery on your prostate to treat BPH.

Sometimes, doctors prescribe dutasteride together with tamsulosin (Flomax) to help relieve BPH symptoms. Tamsulosin works in a different way than dutasteride. It relaxes the muscle around your prostate and bladder, which makes it easier to urinate.

Note: Although dutasteride oral capsule shrinks the enlarged prostate, doctors don’t prescribe it to prevent prostate cancer.

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

Interactions and warnings for dutasteride

Below, you’ll find information about dutasteride’s possible interactions and warnings.

Interactions of dutasteride

Certain things may affect how a drug works. These include getting vaccines, consuming alcohol or certain foods, or taking the drug with other medications. This effect is called a drug interaction.

Before you take dutasteride, ask your doctor to check for possible interactions. Be sure to tell them about any of the following you take or use:

• prescription or over-the-counter drugs
• vitamins, herbs, or supplements

To learn about drug-condition interactions, see the “Warnings for dutasteride” section below.

Warnings for dutasteride

Some people should not take dutasteride, and others should take it cautiously.

Dutasteride could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether dutasteride is a safe option for you.

Ask your doctor about specific warnings for dutasteride, and be sure to tell your doctor about your:

• current health, including any allergies to medications
• past health conditions or surgeries

You should not donate blood while taking dutasteride and for at least 6 months after stopping treatment. This is to prevent a pregnant person from accidentally receiving dutasteride through a blood transfusion. Dutasteride can harm a developing fetus. (See below for more information.)

Allergic reaction

Dutasteride can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.

If you’ve had an allergic reaction to dutasteride or any of its ingredients, your doctor will likely not prescribe dutasteride. They can tell you about medications that are safer options for you.

A mild allergic reaction may cause the following symptoms:

• skin rash
• itchiness
• flushing (temporary warmth, redness, or deepening of skin color)

A severe allergic reaction may cause the following symptoms:

• swelling under your skin, usually in your hands, feet, eyelids, or lips
• swelling of your mouth, throat, or tongue, which can cause breathing problems

If you have an allergic reaction to dutasteride, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.

Overdose of dutasteride

If you take dutasteride, you should not take more than your doctor prescribes. For some drugs, doing so may lead to harmful effects or overdose.

If you think you’ve taken too much dutasteride, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.

Pregnancy or breastfeeding and dutasteride

Information about dutasteride and pregnancy and breastfeeding is described bel­ow.

Dutasteride and pregnancy

Doctors only prescribe dutasteride for males.* The medication can harm a developing fetus. People who are pregnant or who could become pregnant should not take dutasteride.

Also, people who are pregnant or who could become pregnant should not handle dutasteride capsules. The medication can be absorbed through the skin.

Dutasteride and breastfeeding

Doctors only prescribe dutasteride for males.* People who are breastfeeding should not take or handle dutasteride.

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

What to ask your doctor

Let your doctor know if you have questions about dutasteride or would like more details about it.

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

• How long will I need to take dutasteride?
• Will I take dutasteride on its own or with other drugs?
• What other treatment options are available for an enlarged prostate?
• Can dutasteride cause long-term side effects?

Resources

• Dutasteride capsules, for oral use. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/908832b2-21d6-48ae-89cb-f06687321f74/spl-doc#L78e4ca9f-8544-4c94-9864-2bcf1cae195a
• Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm

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.