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dutasteride (Avodart)

Indications: - benign prostatic hypertrophy - androgenetic alopecia Contraindications: 1) no blood donations within 6 months after taking dusteride (to prevent exposure of pregnant women through blood transfusion) 2) women & children 3) prevention of prostate cancer [4] Dosage: 0.5 mg PO QD with or without food Pharmacokinetics: 1) extensively metabolized by liver (cyt P450 3A4) 2) t1/2 of 5 weeks at steady state 3) may take up to 6 months for clinical benefit [2] Adverse effects: 1) fetal abnormalities in male fetus a) absorbed through skin b) may be passed to pregnant woman through blood transfusion 2) impotence < 5% (transient) - erectile dysfunction common [12] - sexual dysfunction may persist after discontinuation [6] - uncommon [8] 3) gynecomastia < 1% 4) possible worsening of heart failure [4] Drug interactions: 1) coadministration of cyt P450 3A4 inhibitors (potential) a) ritonavir, ketoconazole, diltiazem, cimetidine, ciprofloxacin, grapefruit etc b) verapamil & diltiazem decrease dutasteride clearance (amlodipine does not); NOT clinically significant c) has not been studied extensively 2) no known significant drug interactions Mechanism of action: - inhibits testosterone 5-alpha reductase (both isozymes, type 1 & type 2) which converts testosterone to dihydrotestosterone [3,9] - appears to slow clinical progression of BPH [7] - reduces prostate volume & AUA symptom index scores, & increases maximum urinary flow rate (not significantly different from finasteride in clinical effectiveness) [9,10] - dutasteride 0.5 mg QD increases hair count & width & improves hair growth at week 24 compared with finasteride 1 mg QD [11] Clinical trials: - REDEEM trial: low-grade prostate cancer progression was lower with dutasteride than with placebo [5] Notes: Manufacturer: GalaxoSmithKline

Interactions

drug adverse effects of 5-alpha reductase inhibitors

General

5-alpha reductase inhibitor

Properties

Database Correlations

PUBCHEM cid=152945

References

  1. Prescriber's Letter 9(2):S1 2002
  2. Prescriber's Letter 9(12):70 2002
  3. Prescriber's Letter 10(7):37 2003
  4. Andriole GL et al Effect of Dutasteride on the Risk of Prostate Cancer New Eng J Med 2010 362:1192-1202 PMID: 20357281 - Walsh PC Chemoprevention of Prostate Cancer New Eng J Med 2010 362:1237 PMID: 20357287
  5. Fleshner NE et al. Dutasteride in localised prostate cancer management: The REDEEM randomised, double-blind, placebo-controlled trial. Lancet 2012 Jan 24 PMID: 22277570 http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(11)61619-X/fulltext - Parker C. What (if anything) to do about low-risk prostate cancer. Lancet 2012 Jan 24; PMID: 22277569 http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(12)60066-X/fulltext
  6. Prescriber's Letter 20(3): 2013 Persistent Sexual Dysfunction with Finasteride and Dutasteride Detail-Document#: 290308 (subscription needed) http://www.prescribersletter.com
  7. Toren P et al Effect of dutasteride on clinical progression of benign prostatic hyperplasia in asymptomatic men with enlarged prostate: a post hoc analysis of the REDUCE study. BMJ 2013;346:f2109 PMID: 23587564 http://www.bmj.com/content/346/bmj.f2109
  8. Geriatric Review Syllabus, 8th edition (GRS8) Durso SC and Sullivan GN (eds) American Geriatrics Society, 2013 - Geriatric Review Syllabus, 11th edition (GRS11) Harper GM, Lyons WL, Potter JF (eds) American Geriatrics Society, 2022
  9. Nickel JC Comparison of clinical trials with finasteride and dutasteride. Rev Urol. 2004;6 Suppl 9:S31-9. PMID: 16985923 Free PMC Article
  10. Nickel JC, Gilling P, Tammela TL et al Comparison of dutasteride and finasteride for treating benign prostatic hyperplasia: the Enlarged Prostate International Comparator Study (EPICS). BJU Int. 2011 Aug;108(3):388-94. Epub 2011 Jun 1. PMID: 21631695 Free Article
  11. Gubelin Harcha W, Barboza Martinez J, Tsai TF 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 Mar;70(3):489-498.e3. Epub 2014 Jan 9. PMID: 24411083
  12. Medical Knowledge Self Assessment Program (MKSAP) 18, 19 American College of Physicians, Philadelphia 2018, 2022
  13. http://www.fda.gov/cder/consumerinfo/druginfo/avodart.htm
  14. http://www.avodart.com

Component-of

dutasteride/tamsulosin