TLDR Finasteride and dutasteride's effects are mainly due to target binding saturation and slow enzyme turnover.
This study developed a physiologically-based pharmacokinetic (PBPK) model incorporating target-mediated drug disposition (TMDD) and pharmacodynamic (PD) responses for finasteride and dutasteride, which are inhibitors of 5α-reductase (5αR). The model effectively captured the non-linear PK and PD profiles of both drugs, showing that saturation of target binding is the main driver of these profiles, while slow turnover of 5αR contributes to prolonged PD effects. The distinct PD profiles of finasteride and dutasteride are due to their differing inhibition characteristics against 5αR subtypes. These findings support the use of TMDD-PD modeling to optimize clinical dosing and improve therapeutic outcomes for small-molecule drugs with time-dependent target inhibition.
7 citations
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December 2019 in “Pharmaceutics” Taking Dutasteride with Ketoconazole can increase Dutasteride's effects and side effects.
16 citations
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January 2010 in “Drug Metabolism and Pharmacokinetics” Finasteride's effect on hair loss and prostate enlargement depends on its binding to an enzyme, with maximum impact at 0.2 mg dose.
408 citations
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May 2004 in “The Journal of clinical endocrinology and metabolism/Journal of clinical endocrinology & metabolism” Dutasteride more effectively lowers DHT levels in men with enlarged prostates than finasteride.
60 citations
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December 1998 in “Clinical Pharmacology & Therapeutics” Both drugs lower DHT levels, with GI198745 being more effective.
20 citations
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October 1995 in “PubMed” 
70 citations
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June 1993 in “Biochemistry” Finasteride slowly binds to 5-alpha-reductase, affecting enzyme stability and inhibitor potency.
14 citations
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May 2016 in “Therapeutic advances in urology” Taking tadalafil and finasteride together is safe and effective for treating urinary symptoms and erectile dysfunction in men with enlarged prostates.
137 citations
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March 2006 in “Cns Drug Reviews” Finasteride treats enlarged prostate and hair loss, but may cause side effects in some patients.
96 citations
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September 2021 in “International Journal of Molecular Sciences” Chitosan, a natural substance, can be used to create tiny particles that effectively deliver various types of drugs, but more work is needed to improve stability and control of drug release.
January 2023 in “Pharmaceutics” AA–TF#15 significantly promotes hair regrowth and could be an effective treatment for androgenic alopecia.
52 citations
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June 2009 in “Current Opinion in Endocrinology, Diabetes and Obesity” The document concludes that hair transplantation and gene therapy may be important for future hair loss treatment.
