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Dutasteride

AEMPS

Testosterone 5α-reductase types 1 and 2 inhibitors

ATC code: G04CB02

Brand names: Avodart

Updated · Methodology

Indications

A

Benign prostatic hyperplasia

First line

Dutasteride 0.5 mg/day is first-line therapy for benign prostatic hyperplasia. The EPICS study (Andriole 2010, n=1630, head-to-head with finasteride) showed equivalence on symptoms and prostate volume. The CombAT trial (Roehrborn 2010, n=4844, 4 years) confirmed the superiority of dutasteride + tamsulosin combination over monotherapy on progression risk. AUA 2021, EAU 2023, and NG97 guidelines list dutasteride as first-line for BPH with prostate volume >40 mL, equivalent to finasteride.

Sources

  1. AEMPS: Ficha técnica de Dutasterida (2024)
  2. EAU: EAU Guidelines on Management of Non-Neurogenic Male LUTS (2024)

ICD-10: N40 · ICD-11: GA90

B

Androgenetic alopecia

Second line

For androgenetic alopecia, dutasteride is considered an option in patients unresponsive to finasteride. The Olsen 2006 RCT (n=416, head-to-head) showed that dutasteride 2.5 mg/day increased hair count by 17 hairs/cm² more than finasteride 5 mg/day (note: high dose). The Tsunemi 2016 RCT in Japan at 0.5 mg/day showed superiority over placebo. Side effect profile is similar to finasteride; sexual dysfunction and post-finasteride syndrome risks are comparable. and BAD guidelines list dutasteride as second-line for male androgenetic alopecia.

Off-label for alopecia in Russia. Dutasteride is registered for alopecia in South Korea and Japan.

Sources

  1. AEMPS: Ficha técnica de Dutasterida (2024)
  2. AEDV: Documento de consenso sobre alopecia androgenética (2022)

ICD-10: L64 · ICD-11: ED70.0

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

F

Anti-aging and longevity

Not recommended

Dutasteride is a 5α-reductase type I and II inhibitor, more potent than finasteride. It is prescribed for men with benign prostatic hyperplasia (AEMPS Ficha Técnica). Dutasteride is used in women with hair loss and in anti-aging protocols as a more potent 5α-reductase inhibitor. In women, clinical evidence is insufficient and the drug is teratogenic ( category X, risk of male fetal development disruption). Risks of reduced libido, erectile dysfunction, depression, and gynecomastia in men are also described, as is a post-dutasteride syndrome with prolonged adverse effects after discontinuation. If dutasteride was prescribed to a woman or to a man without confirmed BPH diagnosis, consider seeking a second opinion.

Sources

  1. AEMPS: Ficha técnica de Dutasterida (2024)
  2. Cochrane: Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases (2012)
How to read tiers A–F
  • AStrong evidence – first or second line in international guidelines
  • BRecommended in selected cases
  • CStudy data contradict each other
  • DBenefit not proven, no documented harm
  • FDocumented harm, or risk without benefit

Mechanism of action

Dutasteride is a dual inhibitor of 5α-reductase types 1 and 2. Unlike finasteride (type 2 only), dutasteride inhibits both isoforms, producing approximately 90–95% serum DHT reduction versus 65–70% with finasteride. Half-life is about 5 weeks – substantially longer than finasteride (5–8 hours). After discontinuation, DHT returns to baseline over 4–6 months.

Safety

Contraindications

  • Pregnancy (handling of crushed capsules is contraindicated)
  • Age under 18
  • Hypersensitivity
  • Severe hepatic impairment
  • Women (category X)

Serious adverse effects

  • Post-finasteride syndrome (PFS) – persistent sexual, cognitive, and emotional symptoms after discontinuation
  • Depression (rare reports)
  • Male breast cancer (rare)

Common adverse effects

  • Decreased libido (4–6%)
  • Erectile dysfunction (5–9%)
  • Decreased ejaculate volume
  • Gynaecomastia (1–3%)
  • Rash

Pregnancy: can you take Dutasteride?

AEMPS summary of product characteristics (section 4.6): dutasteride is contraindicated in women. Like other 5-alpha reductase inhibitors, it blocks the conversion of testosterone to dihydrotestosterone and, if given to a woman carrying a male fetus, may inhibit development of the fetal external genitalia. Small amounts of dutasteride have been found in the semen of patients taking 0.5 mg daily; it is unknown whether a male fetus can be harmed if the mother is exposed to the patient's semen (the risk is greatest during the first 16 weeks of pregnancy). Patients are advised to use a condom when their partner is or may be pregnant.

Breastfeeding: can you take Dutasteride?

The drug is not intended for women.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Practical notes

Russian practice note

In Russia, dutasteride is registered for BPH; off-label for alopecia. Monthly cost (30 capsules of 0.5 mg) is 1500–3500 ₽. Due to long half-life (5 weeks), blood donation is prohibited for 6 months after the last dose. Dutasteride lowers PSA by approximately half – important for prostate cancer screening interpretation. In men planning conception, dutasteride is recommended to be discontinued 6 months in advance (although clinical data on teratogenicity via semen are absent, theoretical risk persists).
Label mentions17 mentions

Verbatim lines from the interaction sections, in the language of the label

From this drug’s label

  • ModerateCYP3A4 inhibitorsclass named in the label
    «Cytochrome P450 3A Inhibitors: Dutasteride is extensively metabolized in humans by the cytochrome P450 (CYP)3A4 and CYP3A5 isoenzymes. The effect of potent CYP3A4 inhibitors on dutasteride has not…»

    FDA, section 7 · Open on DailyMed

  • ModerateRitonavir
    «DRUG INTERACTIONS: Use with caution in patients taking potent, chronic cytochrome P450 (CYP)3A4 enzyme inhibitors (e.g., ritonavir). (7)»

    FDA, section 7 · Open on DailyMed

  • Digoxin
    «Dutasterida no tiene ningún efecto en la farmacocinética de warfarina o de digoxina. Esto indica que dutasterida no induce/inhibe al CYP2C9 o al transportador de glucoproteína P. Los estudios de…»

    AEMPS, section 4.5 · Open on CIMA

  • Digoxin
    «Digoxin: Dutasteride does not alter the steady-state pharmacokinetics of digoxin when administered concomitantly at a dose of 0.5 mg/day for 3 weeks [see Clinical Pharmacology (12.3)] .»

    FDA, section 7 · Open on DailyMed

  • Diltiazem
    «Uso concomitante con CYP3A4 y/o inhibidores de la glucoproteína P: Dutasterida se elimina fundamentalmente en forma de metabolitos. Los estudios in vitro indican que su metabolismo está catalizado…»

    AEMPS, section 4.5 · Open on CIMA

  • Diltiazem
    «Calcium Channel Antagonists: Coadministration of verapamil or diltiazem decreases dutasteride clearance and leads to increased exposure to dutasteride. The change in dutasteride exposure is not…»

    FDA, section 7 · Open on DailyMed

  • inhibidores del CYP3A4class named in the label
    «Uso concomitante con CYP3A4 y/o inhibidores de la glucoproteína P: Dutasterida se elimina fundamentalmente en forma de metabolitos. Los estudios in vitro indican que su metabolismo está catalizado…»

    AEMPS, section 4.5 · Open on CIMA

  • Itraconazole
    «Uso concomitante con CYP3A4 y/o inhibidores de la glucoproteína P: La combinación a largo plazo de dutasterida con fármacos que son potentes inhibidores de la enzima CYP3A4 (ej., ritonavir…»

    AEMPS, section 4.5 · Open on CIMA

  • Ketoconazole
    «Uso concomitante con CYP3A4 y/o inhibidores de la glucoproteína P: La combinación a largo plazo de dutasterida con fármacos que son potentes inhibidores de la enzima CYP3A4 (ej., ritonavir…»

    AEMPS, section 4.5 · Open on CIMA

  • Ritonavir
    «Uso concomitante con CYP3A4 y/o inhibidores de la glucoproteína P: La combinación a largo plazo de dutasterida con fármacos que son potentes inhibidores de la enzima CYP3A4 (ej., ritonavir…»

    AEMPS, section 4.5 · Open on CIMA

  • Tamsulosin
    «En un pequeño estudio (N=24) de dos semanas de duración en hombres sanos, dutasterida (0,5 mg) no afectó a la farmacocinética de tamsulosina o terazosina. Además, en este estudio no se observó…»

    AEMPS, section 4.5 · Open on CIMA

  • Tamsulosin
    «Alpha-adrenergic Antagonists: The administration of dutasteride in combination with tamsulosin or terazosin has no effect on the steady-state pharmacokinetics of either alpha-adrenergic antagonist…»

    FDA, section 7 · Open on DailyMed

  • Verapamil
    «Uso concomitante con CYP3A4 y/o inhibidores de la glucoproteína P: Dutasterida se elimina fundamentalmente en forma de metabolitos. Los estudios in vitro indican que su metabolismo está catalizado…»

    AEMPS, section 4.5 · Open on CIMA

  • Verapamil
    «Calcium Channel Antagonists: Coadministration of verapamil or diltiazem decreases dutasteride clearance and leads to increased exposure to dutasteride. The change in dutasteride exposure is not…»

    FDA, section 7 · Open on DailyMed

  • Warfarin
    «Dutasterida no tiene ningún efecto en la farmacocinética de warfarina o de digoxina. Esto indica que dutasterida no induce/inhibe al CYP2C9 o al transportador de glucoproteína P. Los estudios de…»

    AEMPS, section 4.5 · Open on CIMA

  • Warfarin
    «Warfarin: Concomitant administration of dutasteride 0.5 mg/day for 3 weeks with warfarin does not alter the steady-state pharmacokinetics of the S- or R-warfarin isomers or alter the effect of…»

    FDA, section 7 · Open on DailyMed

From other drugs’ labels

  • Itraconazole
    «Urológicos: Dutasterida, Imidafenacina, Sildenafilo (disfunción eréctil)»

    AEMPS, section 4.5 · Open on CIMA

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Frequently asked

What is Dutasteride used for?

Dutasteride is evaluated for the following indications with varying evidence strength: Benign prostatic hyperplasia (evidence tier A), Androgenetic alopecia (evidence tier B), Anti-aging and longevity (evidence tier F). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Dutasteride?

Common side effects of Dutasteride (≥ 1 in 100): Decreased libido (4–6%), Erectile dysfunction (5–9%), Decreased ejaculate volume, Gynaecomastia (1–3%), Rash. See the Safety section for uncommon and serious reactions.

Is Dutasteride safe during pregnancy?

AEMPS summary of product characteristics (section 4.6): dutasteride is contraindicated in women. Like other 5-alpha reductase inhibitors, it blocks the conversion of testosterone to dihydrotestosterone and, if given to a woman carrying a male fetus, may inhibit development of the fetal external genitalia. Small amounts of dutasteride have been found in the semen of patients taking 0.5 mg daily; it is unknown whether a male fetus can be harmed if the mother is exposed to the patient's semen (the risk is greatest during the first 16 weeks of pregnancy). Patients are advised to use a condom when their partner is or may be pregnant.

Is Dutasteride compatible with breastfeeding?

The drug is not intended for women.

Who should not take Dutasteride?

Dutasteride is contraindicated in: Pregnancy (handling of crushed capsules is contraindicated); Age under 18; Hypersensitivity; Severe hepatic impairment; Women (category X). Full list in the Safety section.

Official sources

Direct links to regulator labels. Open in a new tab.

Other drugs in this group

Dutasteride + Tamsulosin, Fesoterodine, Finasteride, Mirabegron, Pumpkin seed extract, Silodosin, Tamsulosin, Propiverine