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Dutasteride (Avodart)

5-Alpha Reductase Inhibitorprescriptionoral · inferred

Dual type I and type II 5-alpha reductase inhibitor for BPH and off-label for hair loss. Extremely long terminal half-life (~5 weeks) due to high protein binding (99%) and large volume of distribution. Requires 5-6 months to reach steady state. More potent DHT suppression than finasteride.

Projected serum levels — 0.50 mg, once daily

Dutasteride (Avodart)
Dutasteride (Avodart) modeled serum levels, 0.50 mg once daily over 121 days Population-based pharmacokinetic estimate. Steady state reached after approximately 84 days. 0 5 10 15 20 Day 0 Day 30 Day 61 Day 91 Day 121 Time on a regular schedule ≈ steady state · day 84
Dutasteride (Avodart) modeled serum levels with a loading dose of 1.5 mg, then 0.50 mg once daily The first dose is larger so levels approach steady state faster. 0 5 10 15 20 Day 0 Day 30 Day 61 Day 91 Day 121 Time on a regular schedule

Maintenance schedule: 0.50 mg once daily (oral).

Loading schedule: 1.5 mg on day 1, then 0.50 mg once daily — reaching therapeutic levels sooner.

Modeled steady state after ~84 days: peak ≈ 13.8 mg, trough ≈ 13.6 mg body load. Population-based estimate over 121 days for a 0.50 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
5-Alpha Reductase Inhibitor
Route modeled
Oral
Model confidence
inferred
Half-life
35 days
Common dose
0.50 mg
Suggested maximum
0.50 mg/day
Reference dose range
0.25–0.50 mg (single dose)
Suggested cadence
once daily
Validated against
0.50 mg oral — Cmax 0.004 mg/L at 2.5 h

Documented interactions

  • contraindicated
    Efavirenz (Sustiva) + Dutasteride (Avodart) CYP induction

    Efavirenz (Sustiva) inducer of CYP3A4 predicted to change Dutasteride (Avodart) AUC by ~0.16x

  • contraindicated
    Rifampin + Dutasteride (Avodart) CYP induction

    Rifampin inducer of CYP3A4 predicted to change Dutasteride (Avodart) AUC by ~0.16x

  • danger
    Amlodipine (Norvasc) + Dutasteride (Avodart) CYP inhibition

    Amlodipine (Norvasc) reversible_inhibitor of CYP3A4 predicted to change Dutasteride (Avodart) AUC by ~2.20x

  • danger
    Ashwagandha (KSM-66) + Dutasteride (Avodart) CYP inhibition

    Ashwagandha (KSM-66) reversible_inhibitor of CYP3A4 predicted to change Dutasteride (Avodart) AUC by ~2.20x

  • danger
    Berberine + Dutasteride (Avodart) CYP inhibition

    Berberine reversible_inhibitor of CYP3A4 predicted to change Dutasteride (Avodart) AUC by ~2.20x

  • danger
    Black Seed Oil (Nigella sativa / Thymoquinone) + Dutasteride (Avodart) CYP inhibition

    Black Seed Oil (Nigella sativa / Thymoquinone) reversible_inhibitor of CYP3A4 predicted to change Dutasteride (Avodart) AUC by ~2.20x

Serum checks 201 modeled interaction pairings for dutasteride (avodart) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Efficacy and safety of long-term treatment with the dual 5-alpha reductase inhibitor dutasteride in men with symptomatic BPH Roehrborn CG et al. · European Urology, 2004 DOI

    Pooled analysis of three 2-year phase III trials demonstrating dutasteride 0.5 mg reduced prostate volume by 25%, improved symptom scores, and reduced acute urinary retention risk versus placebo.

  2. Clinical outcomes after combined therapy with dutasteride plus tamsulosin (CombAT trial) Roehrborn CG et al. · European Urology, 2010 DOI

    Four-year CombAT trial of 4,844 men showing dutasteride plus tamsulosin was significantly superior to either monotherapy for reducing BPH progression, urinary retention, and need for surgery.

  3. Comparison of clinical trials with finasteride and dutasteride Debruyne F et al. · Reviews in Urology, 2006 DOI

    Head-to-head review finding dutasteride provides greater DHT suppression (>90% vs ~70% for finasteride) due to dual 5-AR inhibition, with comparable safety profiles.

3 published studies referenced in the app, each with a plain-language summary.