Skip to Content

The originating document has been archived. We cannot confirm the completeness, accuracy and currency of the content.

Dutasteride / Tamsulosin Hydrochloride

Pronunciation: doo-TAS-ter-ide/tam-SOO-loe-sin HYE-droe-KLOR-ide
Class: Androgen hormone inhibitor and alpha-1 adrenergic blocker combination

Trade Names

- Capsules dutasteride 0.5 mg/tamsulosin 0.4 mg



Inhibits the conversion of testosterone to dihydrotestosterone, a potent androgen.


Selectively blocks alpha-1 adrenergic receptors, causing relaxation of prostate smooth muscle and resulting in an increase in urinary flow rate and a reduction in symptoms of benign prostatic hyperplasia (BPH).

Indications and Usage

Treatment of symptomatic BPH in men with enlarged prostate.


Pregnancy; women of childbearing potential; children; hypersensitivity to dutasteride, other 5-alpha reductase inhibitors, tamsulosin, or any component of the product.

Dosage and Administration

Benign prostatic hyperplasia

PO 1 capsule administered once daily approximately 30 min after the same meal each day.

General Advice

  • Swallow capsules whole. Do not crush, cut, or chew.
  • Do not use capsules that are deformed and/or discolored.


Store at 59° to 86°F.

Drug Interactions

Alpha-adrenergic antagonists

The risk of symptomatic hypotension may be increased. Avoid coadministration of other alpha-adrenergic antagonists.

Calcium channel blockers (eg, diltiazem, verapamil)

Coadministration of diltiazem or verapamil may decrease dutasteride clearance, increasing dutasteride exposure. However, the magnitude of the change is not expected to be clinically important. No dutasteride dosage adjustment is recommended.


Tamsulosin clearance may be reduced, increasing tamsulosin plasma concentrations. Coadminister with caution.

CYP2D6 inhibitors (eg, paroxetine, terbinafine)

Tamsulosin plasma concentrations may be elevated, increasing tamsulosin exposure. Use caution when coadministering tamsulosin-containing products with CYP2D6 inhibitors.

CYP3A4 inhibitors

Tamsulosin plasma concentrations may be elevated, increasing tamsulosin exposure. Do not coadminister tamsulosin-containing products with strong CYP3A4 inhibitors (eg, atazanavir, clarithromycin, indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, voriconazole). Use caution when administering tamsulosin-containing products with moderate CYP3A4 inhibitors (eg, erythromycin).


Food does not affect the pharmacokinetics of dutasteride; however, a mean decrease in tamsulosin C max is observed when dutasteride/tamsulosin is administered with food. Administer dutasteride/tamsulosin once daily approximately 30 min after the same meal each day.

Phosphodiesterase type 5 inhibitors (eg, sildenafil)

Because both classes of agents are vasodilators, coadministration may cause symptomatic hypotension. Use with caution.


Available data are inconclusive regarding a drug interaction. Coadminister with caution.

Laboratory Test Interactions

Dutasteride reduces total serum prostatic-specific antigen (PSA) concentrations. The decrease is predictable over the entire range of PSA values, although it may vary in individual patients. Therefore, for interpretation of serial PSA values in a man taking dutasteride, establish a new baseline PSA concentration after 3 to 6 mo of treatment. Use this new value to assess potentially cancer-related PSA changes.

Adverse Reactions


Dizziness (1%).


Ejaculation disorder (9%); impotence (6%); decreased libido (5%); breast disorder including breast tenderness and breast enlargement (1%).


Allergic reactions including angioedema, localized edema, pruritus, rash, serious skin reactions, urticaria, and respiratory problems (postmarketing).



Perform digital rectal exams, as well as other evaluations for prostate cancer, prior to starting therapy and periodically thereafter. Assess patients to rule out other urologic diseases prior to treatment. Carefully monitor patients with large residual urine volume or severely diminished urinary flow for obstructive uropathy.


Category X .




Safety and efficacy not established. Contraindicated for use in children.

Hepatic Function

Use with caution.

Blood donation

Advise men not to donate blood until at least 6 mo after the last dose of dutasteride.

Exposure of women/male fetus risk

Advise women who are pregnant or may become pregnant not to handle the capsules. Dutasteride is absorbed through the skin and could result in unintended fetal exposure. If contact is made with leaking capsules, tell patient to wash the contacted area immediately with soap and water. Dutasteride exposure may result in abnormalities in the genitalia of male fetuses.

Obstructive uropathy

Patients with large residual urine volume or severely diminished urinary flow may not be good candidates for therapy.

Ophthalmic effects

Intraoperative floppy iris syndrome has been observed during cataract surgery in some patients treated with alpha-adrenergic antagonists, including tamsulosin.

Orthostatic hypotension

May occur and result in syncope.


Has been associated with the use of alpha-adrenergic antagonists, including tamsulosin; can lead to permanent impotence if not properly treated.

Prostate cancer

Rule out before starting therapy.

Reproductive effects

Sperm count may be reduced in some patients.

Sulfa allergy

In patients with sulfa allergy, allergic reaction to tamsulosin has been reported rarely.




Patient Information

  • Advise patient to take prescribed dose once daily, about 30 min after the same meal each day.
  • Advise patient that if a dose is missed to take as soon as remembered, but to never take 2 doses the same day.
  • Advise patient that drug does not work immediately and that it may take 3 to 6 mo to experience max benefit.
  • Advise patient to swallow the capsule whole and to not chew, crush, or open the capsule.
  • Caution patient to avoid sudden position changes to prevent orthostatic hypotension. Instruct patient to sit or lie down if orthostatic hypotension does occur.
  • Caution patient that drug may cause dizziness or drowsiness and to use caution while driving or performing other tasks requiring mental alertness until tolerance is determined.
  • Advise patient that ejaculate volume may be decreased during treatment, but that this decrease does not interfere with normal sexual function.
  • Instruct patient to not stop taking the medication when symptoms have improved.
  • Caution patient to not allow women who are or may become pregnant to handle the medication because of the risk of absorption though the skin and the risk to a developing male fetus. If contact is made with a leaking capsule, advise patient to wash the contacted area immediately with soap and water.
  • Advise patient that impotence, decreased libido, and ejaculation disorder may occur with therapy, but that these symptoms should lessen as treatment continues.
  • Inform patients about the possibility of priapism and that, while this reaction is rare, it can lead to permanent erectile dysfunction if not brought to immediate medical attention.
  • Advise patient against donating blood for at least 6 mo following discontinuation of therapy to prevent pregnant women from receiving dutasteride through a blood transfusion.
  • Advise patients considering cataract surgery to tell their ophthalmologist that they take or have taken dutasteride/tamsulosin.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.