Dutasteride is a medicine used for the symptoms of an enlarged prostate (benign prostatic hyperplasia). It blocks the conversion of testosterone to its more active form, shrinking the prostate. Effects take several months to appear.
Also known as: Avodart
Ketoconazole (or other strong CYP3A4 inhibitors) can raise dutasteride blood levels. Use with caution and watch for side effects.
Dutasteride is eliminated mainly by hepatic metabolism (CYP3A4/3A5). Potent inhibitors of this enzyme raise serum concentrations; in population studies, moderate inhibitors (verapamil, diltiazem) increased concentrations 1.6–1.8-fold. The long half-life may be further prolonged, taking more than 6 months to reach a new steady state.
CYP3A4: dutasteride is eliminated by CYP3A4/3A5 metabolism; strong inhibitors (ketoconazole, itraconazole, ritonavir) raise serum concentrations. In long-term use, consider reducing dose frequency.
CYP3A4/3A5 inhibition, reducing dutasteride elimination.
Dutasteride adverse effects (decreased libido, erectile dysfunction, ejaculation disorders, gynaecomastia).
Gynaecomastia, persistent sexual dysfunction.
Use with caution; in long-term use with strong inhibitors, consider reducing dose frequency; watch for adverse effects.
DailyMed/FDA (NIH/NLM) — approved Dutasteride label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=947644ea-bc35-41df-8a7a-874360c90192 ; approved Ketoconazole label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f162e616-21b4-49b1-b437-15e21001a6f0 ; EMC-UK (MHRA) — approved Dutasteride SmPC: https://www.medicines.org.uk/emc/product/102479/smpc ; PubMed — https://pubmed.ncbi.nlm.nih.gov/31835695/ ; Prontuário Terapêutico do INFARMED (11th ed., 2012)
Itraconazole can raise dutasteride blood levels. Use with caution and watch for side effects.
Itraconazole inhibits CYP3A4, the enzyme responsible for dutasteride elimination. Increased exposure and the drug long half-life justify caution; in long-term use, consider reducing dose frequency.
CYP3A4: itraconazole (strong inhibitor) raises dutasteride concentrations, with a potentially prolonged half-life; monitor tolerability.
CYP3A4 inhibition, reducing dutasteride elimination.
Dutasteride adverse effects.
Gynaecomastia, persistent sexual dysfunction.
Use with caution; watch for adverse effects; consider reducing dose frequency in long-term use.
DailyMed/FDA (NIH/NLM) — approved Dutasteride label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=947644ea-bc35-41df-8a7a-874360c90192 ; approved Itraconazole label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a4d555fa-787c-40fb-bb7d-b0d4f7318fd0 ; EMC-UK (MHRA) — approved Dutasteride SmPC: https://www.medicines.org.uk/emc/product/102479/smpc ; Prontuário Terapêutico do INFARMED (11th ed., 2012)
Dutasteride may be taken with or without food, with no relevant documented food interactions.
Swallow the capsule whole; may be taken with or without food.
DailyMed/FDA (NIH/NLM) — approved Dutasteride label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=947644ea-bc35-41df-8a7a-874360c90192
Dutasteride reduces serum PSA by about 50% and may increase the risk of high-grade prostate cancer; it is not approved for prostate cancer prevention.
Establish a new PSA baseline after 6 months of treatment and monitor regularly; evaluate any confirmed PSA rise.
DailyMed/FDA (NIH/NLM) — approved Dutasteride label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=947644ea-bc35-41df-8a7a-874360c90192 ; Prontuário Terapêutico do INFARMED (11th ed., 2012)
Contraindicated in women and in women of child-bearing potential: dutasteride can inhibit the development of the external genitalia of a male fetus.
Contraindicated in pregnancy; pregnant women or those who may become pregnant must not handle the capsules.
Not indicated in women; no data on milk excretion.
When the partner is or may be pregnant, condom use is recommended (dutasteride detected in semen); do not donate blood until 6 months after the last dose.
DailyMed/FDA (NIH/NLM) — approved Dutasteride label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=947644ea-bc35-41df-8a7a-874360c90192 ; EMC-UK (MHRA) — approved Dutasteride SmPC: https://www.medicines.org.uk/emc/product/102479/smpc ; Prontuário Terapêutico do INFARMED (11th ed., 2012)
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
5-alpha-reductase inhibitor used in benign prostatic hyperplasia. It reduces serum DHT by 85 to 90% within the first 1 to 2 weeks of daily treatment; with 0.5 mg/day for 4 years, the median DHT reduction was 94 to 95%, with an increase in testosterone within the physiological range.
Competitively and specifically inhibits both isoforms of 5-alpha-reductase (type 1 and type 2), blocking the conversion of testosterone to dihydrotestosterone (DHT), the androgen responsible for prostate development and growth. It does not bind to the androgen receptor.
Peak serum concentrations occur 2 to 3 hours after dosing. Absolute bioavailability is approximately 60% (40 to 94%); food reduces Cmax by 10 to 15% without clinical significance. The volume of distribution is large (300 to 500 L) and albumin binding is 99%.
Extensively metabolised in the liver, mainly by CYP3A4 and CYP3A5. Dutasteride and its metabolites are excreted mainly in faeces (about 5% unchanged and 40% as metabolites); less than 1% is recovered unchanged in urine.
The terminal half-life at steady state is approximately 5 weeks; concentrations reach 65% of steady state after 1 month and about 90% after 3 months, remaining detectable for 4 to 6 months after discontinuation.
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
