Dutasteride

• Benign Prostatic Hyperplasia (BPH):
  Treatment of symptomatic benign prostatic hyperplasia to improve urinary flow and reduce the risk of acute urinary retention and the need for surgery.
• Off-label/Clinically Accepted Uses:
• Androgenic alopecia (male pattern hair loss) — limited evidence and not officially approved.
• Prevention of prostate cancer (investigational use).

• Adults (Male Only):
• Recommended dose: 0.5 mg orally once daily.
• Capsules should be swallowed whole with or without food.
• Duration:
• Long-term therapy is usually necessary. Clinical benefits may take 3 to 6 months or longer.
• Therapy may be continued indefinitely under physician supervision.
• Pediatrics:
• Safety and efficacy not established; not recommended.
• Elderly:
• No dose adjustment necessary.
• Renal/Hepatic Impairment:
• No dose adjustment required in mild to moderate impairment.
• Use with caution in severe hepatic impairment; insufficient data available.

Dutasteride is a selective inhibitor of both type 1 and type 2 isoforms of 5-alpha-reductase enzyme. This enzyme converts testosterone into dihydrotestosterone (DHT), a potent androgen that stimulates prostate growth. By inhibiting 5-alpha-reductase, dutasteride reduces serum and intraprostatic DHT concentrations, leading to shrinkage of the enlarged prostate gland, improved urinary flow, and symptom relief in BPH. Inhibiting DHT also decreases androgenic stimulation related to hair follicle miniaturization in androgenic alopecia.

• Absorption:
  Well absorbed orally; peak plasma concentration achieved within 2–3 hours.
• Bioavailability:
  Approximately 60%.
• Distribution:
  Widely distributed; highly lipophilic with large volume of distribution (~300 L).
  Plasma protein binding >99%.
• Metabolism:
  Extensively metabolized by hepatic CYP3A4 isoenzyme to active metabolites.
• Half-life:
  Terminal elimination half-life approximately 5 weeks due to extensive tissue binding.
• Elimination:
  Excreted primarily via feces; minimal renal excretion.

• Pregnancy:
  Classified as FDA Pregnancy Category X. Contraindicated in women who are or may become pregnant due to risk of fetal harm, particularly to male fetuses (abnormal genital development). Handling of capsules by pregnant women should be avoided.
• Lactation:
  Safety in breastfeeding not established; women should avoid exposure.

• Primary Therapeutic Class: 5-alpha-reductase inhibitor
• Subclass: Dual-type (Type 1 and Type 2) 5-alpha-reductase inhibitor

• Known hypersensitivity to dutasteride or any excipients.
• Women who are or may become pregnant.
• Pediatric patients (safety and efficacy not established).

• Pregnancy Risk:
  Potential for fetal harm; pregnant women must avoid exposure.
• Male Fertility:
  May reduce sperm count; counsel patients regarding potential fertility effects.
• Prostate Cancer:
  May decrease PSA levels; interpret PSA results carefully as it may mask prostate cancer detection.
• Breast Disorders:
  Rare reports of gynecomastia and breast tenderness.
• Liver Function:
  Use with caution in severe hepatic impairment.

Common:

• Impotence
• Decreased libido
• Ejaculation disorders (reduced volume)
• Breast tenderness or enlargement (gynecomastia)

Less Common/Rare:

• Allergic reactions (rash, swelling)
• Testicular pain
• Depression
• Hypersensitivity reactions

• No significant drug interactions reported.
• Metabolized by CYP3A4; caution with strong CYP3A4 inhibitors or inducers that may alter dutasteride levels.

• Updated guidelines recommend dutasteride as a first-line medical therapy for moderate to severe BPH.
• Long-term studies confirm safety with extended use and reduced risk of BPH progression.
• Recent warnings reinforce strict avoidance in women of childbearing potential.

• Store at 20°C to 25°C (68°F to 77°F).
• Protect from moisture and light.
• Keep capsules in original container until use.
• Keep out of reach of children and women of childbearing age.