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Dutasteride Side Effects

For the Consumer

Applies to dutasteride: oral capsule liquid filled

In addition to its needed effects, some unwanted effects may be caused by dutasteride. In the event that any of these side effects do occur, they may require medical attention.

Severity: Major

You should check with your doctor immediately if any of these side effects occur when taking dutasteride:

  • Chest pain or discomfort
  • dilated neck veins
  • extreme fatigue
  • irregular breathing
  • irregular heartbeat
  • shortness of breath
  • swelling of the face, fingers, feet, or lower legs
  • weight gain
  • wheezing
Incidence not known:
  • Blistering, flaking, or peeling of the skin
  • cough
  • difficulty with swallowing
  • dizziness
  • fast heartbeat
  • hives or welts
  • itching skin
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • redness of the skin
  • skin rash
  • tightness in the chest
  • unusual tiredness or weakness
  • wheezing

Severity: Minor

Some of the side effects that can occur with dutasteride may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

Less common:
  • Abnormal ejaculation
  • decreased interest in sexual intercourse
  • decreased sexual performance or desire
  • impotence
  • inability to have or keep an erection
  • loss in sexual ability, desire, drive, or performance
  • pain, soreness, swelling, or discharge from the breast or breasts

For Healthcare Professionals

Applies to dutasteride: oral capsule


In general, side effects have been mild and transient.[Ref]


The incidence of sexual adverse events has been reported to decrease with duration of treatment. After the first 6 months of treatment, the incidence of onset of impotence, decreased libido, ejaculation disorders, or gynecomastia was less than 1%. The adverse event profile for one two year study (n=677) reported that the onset of drug-related events was lower during the second year of treatment compared with the first , except for gynecomastia which was reported at 1% during the first year and 2% during the second year.[Ref]

Genitourinary side effects including impotence (up to 4.7%), decreased libido (up to 3.0%), ejaculation disorders (up to 1.4%), and gynecomastia (up to 1.1%) have been reported.

Postmarketing genitourinary side effects include testicular pain and swelling.[Ref]


Hypersensitivity side effects have been reported including allergic reactions such as angioedema, rash, pruritus, urticaria, and localized edema. Serious skin reactions have been reported during postmarketing experience.[Ref]


In the CombAT study (to determine if combination therapy with dutasteride and tamsulosin is more effective than either monotherapy alone), after 4 years of treatment, the incidence of the composite term cardiac failure in the combination therapy group (12/1,610; 0.7%) was higher than in either monotherapy group: Dutasteride, 2/1,623 (0.1%) and tamsulosin, 9/1,611 (0.6%). Composite cardiac failure was also examined in a separate 4-year placebo-controlled trial evaluating dutasteride in men at risk for development of prostate cancer. The incidence of cardiac failure in subjects taking dutasteride was 0.6% (26/4,105) compared to 0.4% (15/4,126) in subjects on placebo. A majority of subjects with cardiac failure in both studies had comorbidities associated with an increased risk of cardiac failure. Therefore, the clinical significance of the numerical imbalances in cardiac failure is unknown. No causal relationship between dutasteride, alone or in combination with tamsulosin, and cardiac failure has been established. No imbalance was observed in the incidence of overall cardiovascular adverse events in either study.


Postmarketing oncologic side effects have included male breast cancer.


Postmarketing psychiatric side effects have included depressed mood.


1. "Product Information. Duagen (dutasteride)." GlaxoSmithKline Healthcare, Pittsburgh, PA.

Not all side effects for dutasteride may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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