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Avodart Non-Responder Profile: Who Doesn't Respond to Dutasteride and Why

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At a glance

  • Drug / dutasteride 0.5 mg capsule once daily (Avodart)
  • Approved use / symptomatic BPH, alone or with tamsulosin; hair loss is off-label [4]
  • DHT effect / median serum DHT down 85% at 1 week, 90% at 2 weeks [4]
  • Time to steady state / about 65% at 1 month, about 90% at 3 months [4]
  • Half-life / about 5 weeks at steady state [4]
  • Hair-loss trial length / 24 weeks to 6 months [1][2][3]
  • Hair count on 0.5 mg / +12.2 per cm2 vs +4.7 on placebo at 6 months [2]
  • Common adverse reactions / impotence 4.7% vs 1.7% on placebo, months 0 to 6 [4]

Is there a published non-responder profile?

The hair-loss trials report hair count, hair width and photographic outcomes by dose group. In the abstracts, results are given as average change per group, and individual men who did not respond are not described [1][2][3]. The 2006 trial also measured scalp and serum DHT, which fell in a dose-dependent way [3].

Dutasteride is approved for symptomatic benign prostatic hyperplasia, and hair loss is an off-label use [4]. All three hair-loss trials were short: 24 weeks or 6 months [1][2][3].

What the hair-loss trials measured

A 2010 phase III trial randomized 153 men aged 18 to 49 with male pattern hair loss to dutasteride 0.5 mg or placebo for six months. Mean hair count rose 12.2 per cm2 on dutasteride and 4.7 per cm2 on placebo (P=.0319) [2].

A 2014 trial randomized 917 men aged 20 to 50 to dutasteride 0.02, 0.1 or 0.5 mg, finasteride 1 mg or placebo for 24 weeks. Dutasteride 0.5 mg increased hair count more than finasteride 1 mg (P=.003) and placebo (P<.001), and hair count rose with dose across the dutasteride arms [1].

A 2006 trial randomized 416 men aged 21 to 45 to dutasteride 0.05, 0.1, 0.5 or 2.5 mg, finasteride 5 mg or placebo for 24 weeks. Dutasteride 2.5 mg was superior to finasteride at 12 and 24 weeks [3].

Dose, DHT and steady state

Dutasteride inhibits both type 1 and type 2 5-alpha-reductase and does not bind the androgen receptor [4]. For BPH, the label dose is one 0.5 mg capsule once daily. The label says to swallow it whole because contact with the contents may irritate the mouth and throat [4]. Median serum DHT fell 85% after one week, 90% after two weeks, 94% at one year and 95% at three and four years. Median testosterone rose about 19% to 26% and stayed within the physiologic range [4]. Steady state is about 65% complete at one month and about 90% at three months, with a terminal half-life of about 5 weeks [4].

Adverse reactions the label reports

In pooled 2-year BPH trials (2,167 on Avodart, 2,158 on placebo; mean age 66), months 0 to 6 brought impotence 4.7% vs 1.7%, decreased libido 3.0% vs 1.4%, ejaculation disorders 1.4% vs 0.5% and breast disorders 0.5% vs 0.2% [4]. The label states these sexual reactions may persist after discontinuation and that dutasteride's role in that persistence is unknown [4].

Frequently asked questions

What hair-count results did the hair-loss trials show?
In 153 men over 6 months, mean hair count rose 12.2 per cm2 on dutasteride 0.5 mg vs 4.7 per cm2 on placebo (P=.0319) [2]. In 917 men over 24 weeks, 0.5 mg beat finasteride 1 mg (P=.003) and placebo (P<.001), with hair count rising dose-dependently [1].
How long did the hair-loss trials last?
The 2014 and 2006 trials ran 24 weeks and the 2010 trial ran 6 months. The 2014 and 2010 authors list the short duration as a limitation [1][2][3].
Is hair loss an approved use of dutasteride?
No. Avodart is approved for symptomatic benign prostatic hyperplasia in men with an enlarged prostate, alone or in combination with tamsulosin, and hair loss is an off-label use [4].

References

  1. Gubelin Harcha W, Barboza Martínez J, Tsai TF, Katsuoka K, Kawashima M, Tsuboi R, et al. A randomized, active- and placebo-controlled study of the efficacy and safety of different doses of dutasteride versus placebo and finasteride in the treatment of male subjects with androgenetic alopecia. J Am Acad Dermatol. 2014;70(3):489-498.e3. A randomized, active- and placebo-controlled study of the efficacy and safety of different doses of dutasteride versus placebo and finasteride in the treatment of male subjects with androgenetic alopecia
  2. Eun HC, Kwon OS, Yeon JH, Shin HS, Kim BY, Ro BI, et al. Efficacy, safety, and tolerability of dutasteride 0.5 mg once daily in male patients with male pattern hair loss: a randomized, double-blind, placebo-controlled, phase III study. J Am Acad Dermatol. 2010;63(2):252-8. Efficacy, safety, and tolerability of dutasteride 0.5 mg once daily in male patients with male pattern hair loss: a randomized, double-blind, placebo-controlled, phase III study
  3. Olsen EA, Hordinsky M, Whiting D, Stough D, Hobbs S, Ellis ML, et al. The importance of dual 5alpha-reductase inhibition in the treatment of male pattern hair loss: results of a randomized placebo-controlled study of dutasteride versus finasteride. J Am Acad Dermatol. 2006;55(6):1014-23. The importance of dual 5alpha-reductase inhibition in the treatment of male pattern hair loss: results of a randomized placebo-controlled study of dutasteride versus finasteride
  4. U.S. National Library of Medicine, DailyMed. Avodart (dutasteride) soft gelatin capsules, Waylis Therapeutics prescribing information. Avodart (dutasteride) soft gelatin capsules, Waylis Therapeutics label
Evidence overview for reviews dutasteride: Avodart Non-Responder Profile: Who Doesn't Respond to Dutasteride and Why