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Avodart Regret, Stopping, and Restarting: What Real Users and Clinical Data Actually Show

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At a glance

  • Drug / dutasteride 0.5 mg capsule (Avodart)
  • Approved use / symptomatic BPH; hair loss is off-label [1]
  • Terminal half-life / about 5 weeks [1]
  • Blood donation / the label says not to donate until at least 6 months after the last dose [1]
  • Impotence, months 0 to 6 / 4.7% vs 1.7% on placebo [1]
  • Decreased libido, months 0 to 6 / 3.0% vs 1.4% [1]
  • Persistence after stopping / label says sexual reactions may persist; role of the drug unknown [1]

Side effects reported in the trials

The pooled 2-year BPH trials included 2,167 men taking Avodart and 2,158 taking placebo; their mean age was 66 [1]. In the first six months, impotence was reported by 4.7% of men on dutasteride versus 1.7% on placebo, decreased libido by 3.0% versus 1.4%, ejaculation disorders by 1.4% versus 0.5%, and breast disorders by 0.5% versus 0.2% [1]. In the placebo-controlled trials, 4% of men on Avodart and 3% on placebo withdrew because of adverse reactions, and the most common reason was impotence (1%) [1].

Hair-loss trials are shorter. In a 24-week trial of 917 men aged 20 to 50 with androgenetic alopecia, dutasteride 0.5 mg improved hair count (P=.003) and hair width (P=.004) compared with finasteride 1 mg, and improved both versus placebo (P<.001), with similar adverse events across groups [2]. A meta-analysis of 15 placebo-controlled trials in 4,495 men found a relative risk of sexual dysfunction of 1.57 for 5-alpha-reductase inhibitors overall; for dutasteride 0.5 mg it was 1.37 (95% CI 0.81 to 2.32), not statistically significant, with few dutasteride trials [5].

What the label says can outlast the drug

The Avodart label adds a footnote to its adverse-reaction table: the sexual reactions listed may persist after treatment is discontinued, and the role of dutasteride in that persistence is unknown [1]. In healthy men treated for 52 weeks, total sperm count fell 23%, semen volume 26% and sperm motility 18% versus placebo, and total sperm count was still 23% below baseline 24 weeks after stopping; the clinical significance for an individual man's fertility is not known [1].

Restarting: what the evidence does and does not show

The labeled dose is 0.5 mg once daily, swallowed whole, with or without food [1]. Because the hair-loss trials ran 24 weeks or 6 months and report no results off drug, they do not show hair loss after stopping or regrowth after restarting [2][3][4].

Frequently asked questions

Is dutasteride FDA-approved for hair loss?
No. Avodart is indicated only for symptomatic benign prostatic hyperplasia in men with an enlarged prostate, alone or combined with tamsulosin, and is not approved for prevention of prostate cancer. Hair-loss use is off-label [1].
How long does dutasteride stay in the body after the last dose?
The terminal half-life is about 5 weeks, and serum levels stay above 0.1 ng/mL for up to 4 to 6 months after stopping. The label says men treated with Avodart should not donate blood until at least 6 months have passed since their last dose [1].
Do sexual side effects go away after stopping dutasteride?
The Avodart label states that the sexual adverse reactions associated with dutasteride may persist after treatment is discontinued and that the role of dutasteride in that persistence is unknown [1]. In the pooled 2-year BPH trials, impotence was reported by 4.7% of men on dutasteride versus 1.7% on placebo during the first 6 months [1].
Can dutasteride be taken every other day?
The labeled schedule is 0.5 mg once daily [1]. The hair-loss trials used daily dosing, and none of them tested alternate-day or less frequent dosing [2][3][4].

References

  1. U.S. National Library of Medicine, DailyMed. Avodart (dutasteride) soft gelatin capsules, Waylis Therapeutics prescribing information. Avodart (dutasteride) soft gelatin capsules, Waylis Therapeutics label
  2. 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
  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. 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
  5. Lee S, Lee YB, Choe SJ, Lee WS. Adverse Sexual Effects of Treatment with Finasteride or Dutasteride for Male Androgenetic Alopecia: A Systematic Review and Meta-analysis. Acta Derm Venereol. 2019;99(1):12-17. Adverse Sexual Effects of Treatment with Finasteride or Dutasteride for Male Androgenetic Alopecia: A Systematic Review and Meta-analysis
Evidence overview for reviews dutasteride: Avodart Regret, Stopping, and Restarting: What Real Users and Clinical Data Actually Show