II. Indications
-
Benign Prostatic Hyperplasia
- BPH-Associated Gross Hematuria
- Large Prostate size >40 ml (see PSA to estimate Prostate size)
-
Androgenic Alopecia in males (Finasteride)
- Adjunct to hair Transplantation
III. Mechanism
- Inhibits Testosterone to Dihydrotestosterone conversion
- Competitive Inhibition of enzyme 5a-reductase
- Finasteride inhibits Type II 5a reductase
- Dutasteride inhibits both Type I and II 5a reductase
- Reduces volume of Prostate
- Improves urine Blood Flow
IV. Preparations
- Finasteride (Propecia, Proscar)
- Dutasteride (Avodart)
V. Dosing
-
Alopecia
- Finasteride 1 mg orally daily (or one quarter tablet daily of the 5 mg tablet)
-
Benign Prostatic Hyperplasia (typically used in combination with Tamsulosin or Terazosin)
- Finasteride 5 mg orally daily
- Dutasteride 0.5 mg orally daily
VI. Advantages: Finasteride
-
Alopecia
- Increases Hair Growth and reduces Hair Loss
- Effective on vertex and anterior mid-scalp
- Side effects uncommon
-
Benign Prostatic Hyperplasia
- May be more effective in men with large Prostate
VII. Disadvantages: Finasteride
-
Alopecia
- Improvements take 6-12 months
- Any benefits are lost when medication is stopped
- Finasteride 1 mg tablet is much more expensive then 5 mg tablet
- Consider quartering the 5 mg tablet (generic, cheap) which drops the cost considerably
-
Benign Prostatic Hyperplasia
- Increased urine flow not evident for 6-12 months
- Mediocre effects on obstructive symptoms and urine flow (better in Prostate size >40 ml)
- Less effective than alpha blockers (e.g. Hytrin)
- Less effective than surgery
- Only as effective as Saw Palmetto
- Highly effective in reducing BPH-related Gross Hematuria (80%)
VIII. Adverse Effects
- Suicidal Ideation
- Decreased Libido or Erectile Dysfunction (2%)
- Longterm Erectile Dysfunction may persists even after stopping Finasteride in up to 0.1% of patients
- Irwig (2012) J Sex Med 9(11): 2927-32 [PubMed]
- Lowers Prostate Specific Antigen (PSA) Values by 30-50%
- Obtain PSA baseline prior to starting Finasteride
- Double the actual PSA to determine work-up
- Obtain baseline Digital Rectal Exam
- Longterm use associated with high grade Prostate Cancer
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Related Studies
| finasteride (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| FINASTERIDE 1 MG TABLET | Generic | $0.04 each |
| FINASTERIDE 5 MG TABLET | Generic | $0.06 each |
| propecia (on 10/19/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| PROPECIA 1 MG TABLET | Generic | $0.04 each |
| dutasteride (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| DUTASTERIDE 0.5 MG CAPSULE | Generic | $0.19 each |
| DUTASTERIDE-TAMSULOSIN 0.5-0.4 | Generic | $2.02 each |
| avodart (on 11/4/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| AVODART 0.5 MG SOFTGEL | Generic | $0.19 each |