7 Dutasteride Side Effects and How to Manage Them

If you have benign prostatic hyperplasia (BPH), your healthcare professional (HCP) may prescribe dutasteride (Avodart) to help improve symptoms of an enlarged prostate. BPH can cause troublesome symptoms like frequent urination and difficulty starting or stopping a urinary stream.

Dutasteride is an effective medication for many men. It treats BPH by blocking a form of testosterone that contributes to prostate growth. As the prostate becomes smaller over time, it becomes easier to urinate.

But since dutasteride affects testosterone, it can have effects on other areas of your body too. This may contribute to side effects such as erectile dysfunction and a lower sex drive.

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Dutasteride side effects at a glance

All 5-alpha reductase inhibitors, such as dutasteride, can cause similar side effects. Mild side effects can often be managed at home, but more serious side effects are possible.

Common dutasteride side effects include:

• Erectile dysfunction (ED)

• Lower sex drive (libido)

• Breast tenderness

• Breast enlargement

• Difficulty ejaculating

• Dizziness

• Mood changes

• Lower sperm count

Less common, but potentially serious, dutasteride side effects include:

• Higher risk of prostate cancer

• Birth defects

• Allergic reaction

Below, we’ll review seven notable dutasteride side effects and how to manage them.

1. Erectile dysfunction

ED is the most common side effect of dutasteride. The medication may make it more difficult to achieve and maintain an erection. Although only about 5% of people who took dutasteride in clinical studies reported symptoms of ED, it can be frustrating if you experience it. ED is most common within the first 6 months of starting dutasteride and generally gets better over time.

These symptoms happen with dutasteride because it blocks testosterone’s conversion to its more active form, dihydrotestosterone. Testosterone plays a key role in regulating your sexual response; less testosterone in the body can affect sexual function.

If ED is a concern, speak with your HCP. Depending on your situation, they may want to lower your dose of dutasteride or prescribe an alternative BPH treatment that doesn’t have as many sexual side effects, such as tamsulosin (Flomax) or doxazosin (Cardura). They may also recommend medications that can help with ED, such as tadalafil (Cialis) or sildenafil (Viagra).

2. Lower sex drive

A lower-than-normal sex drive is another common dutasteride side effect. Similar to ED symptoms, lower libido is more common within the first 6 months of taking dutasteride and usually gets better over time.

Some ways to address a lower sex drive include getting enough sleep, maintaining a healthy diet, and managing stress (when possible). But if measures like these aren’t enough and low libido is affecting your relationships or confidence, speak to your HCP. They can talk to you about potentially adjusting your BPH medication regimen.

3. Breast changes

Breast changes are possible with dutasteride. It can cause breast enlargement and tenderness in men, also known as gynecomastia. It’s less common than other side effects, though. In initial studies, breast changes were reported in about 1% of people taking dutasteride. It’s thought to happen because 5-alpha reductase inhibitors like dutasteride can cause an imbalance of estrogen in the body compared with androgens (male hormones).

If breast changes become bothersome while taking dutasteride, let your HCP know. They may be able to switch you to an alternative medication for BPH that doesn’t carry the risk of breast enlargement or tenderness.

If you notice certain changes in your breasts — such as pain, nipple discharge, or lumps — let your HCP know right away. These could be signs of a more serious problem, such as breast cancer. Breast cancer is possible in men — not just women.

4. Dizziness

In some cases, dutasteride may contribute to dizziness. If you feel dizzy or lightheaded, it’s important to find a place to sit or lie down. To be safe, until you know how dutasteride affects you, it’s best to avoid driving or performing other tasks that require you to be alert.

If your dizziness becomes bothersome or doesn’t improve over time, let your HCP know. Something else could be going on. Dizziness has many possible causes — medications are only one potential culprit.

5. Mood changes

Mood changes, such as symptoms of depression, are another possible side effect of dutasteride. The reason why this happens isn’t proven, but it may be related to how dutasteride can decrease the amount of certain steroids in the brain.

If this happens to you, there are ways to take matters into your own hands. A number of medication-free ways are available to combat mood changes, including exercising regularly, eating a healthy diet, and prioritizing good sleep hygiene habits. Little steps like these can go a long way.

If changes in your mood become bothersome or don’t get better over time, speak with your healthcare team about ways to help manage these symptoms. They may recommend treatment options for depression, such as antidepressants, to help you get back to feeling like yourself.

6. Prostate cancer risk

Dutasteride may raise your risk of high-grade prostate cancer. High-grade prostate cancer tends to grow more quickly and be more aggressive than other types of prostate cancer. But dutasteride has also been shown to lower the risk of some lower-grade prostate cancers.

Common signs and symptoms of prostate cancer to look out for include:

• Trouble urinating

• Blood in the urine or semen

• ED

• Joint and bone pain

• Fatigue and weakness

Let your HCP know if you’re having symptoms that could be a sign of prostate cancer. They may want to do further testing to investigate the issue.

Good to know: The overall risk of high-grade prostate cancer is low while taking dutasteride, but it’s still possible. Speak with your healthcare team if you have concerns about your risk or family history of prostate cancer.

7. Harm to a fetus

Women who are pregnant or planning to become pregnant shouldn’t take dutasteride. This is because it can cause genital abnormalities in developing male babies. Pregnant women shouldn’t even touch or handle dutasteride capsules, since small amounts can be absorbed through the skin. If you’re pregnant and you think you’ve been exposed to dutasteride, wash the exposed area thoroughly with soap and water right away.

If you’re taking dutasteride, you shouldn’t donate blood for at least 6 months after your last dose. This will prevent your blood from potentially being donated to a woman who is pregnant.

When to contact a healthcare professional about dutasteride side effects

Most of dutasteride’s side effects are mild. And they usually ease with time as your body gets used to the medication. But if any side effect becomes bothersome or doesn’t go away, let your HCP know without delay. They can recommend ways to help, such as by lowering your dose or switching to another treatment. 

In some situations, it’s a good idea to reach out to your HCP more promptly to talk about next steps. These include:

• Breast changes, such as lumps, pain, or nipple discharge

• Dizziness that doesn’t go away or gets worse

• Prostate cancer symptoms such as blood in the urine or semen, pelvic or back pain, or pain while urinating

If you’re experiencing an allergic reaction to dutasteride — including symptoms such as hives, trouble breathing, or throat swelling — call 911 or go to the nearest ER right away.

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Written by:

Sonja Jacobsen, PharmD, BCPS, BCOP

Sonja Jacobsen, PharmD, BCPS, BCOP,  is a clinical oncology pharmacy specialist currently practicing in Seattle. She has been practicing as a pharmacist since 2015 and is licensed to practice in Washington state and North Carolina.

Edited by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

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