Finasteride (Finapt) Indications
Important Note: Drug Name Clarification
The question asks about "Finapt," but the evidence provided concerns finasteride. Finapt is actually the brand name for iloperidone (an antipsychotic medication), which is a completely different drug. The following answer addresses finasteride indications based on the provided evidence.
FDA-Approved Indications
Finasteride is FDA-approved for two primary indications: symptomatic benign prostatic hyperplasia (BPH) in men with enlarged prostates, and male pattern hair loss (androgenetic alopecia). 1
1. Benign Prostatic Hyperplasia (BPH)
As monotherapy, finasteride is indicated for men with symptomatic BPH and an enlarged prostate to:
- Improve urinary symptoms 1
- Reduce the risk of acute urinary retention 1
- Reduce the need for surgical intervention, including transurethral resection of the prostate (TURP) and prostatectomy 1
The standard dose for BPH is 5 mg daily. 2, 3
In combination therapy, finasteride with the alpha-blocker doxazosin is indicated to reduce the risk of symptomatic BPH progression (defined as a confirmed ≥4 point increase in American Urological Association symptom score). 1
Critical Caveat for BPH Treatment
Finasteride is ineffective in men with lower urinary tract symptoms who do not have prostatic enlargement. 4 The drug works by reducing prostate volume by approximately 20-25%, so patients without glandular enlargement will not benefit. 4, 2
Therapy must be continued for at least 6 months before evaluating clinical response, as maximal effects take time to develop. 3
2. Male Pattern Hair Loss (Androgenetic Alopecia)
Finasteride 1 mg daily is indicated for treating male pattern hair loss in men. 5, 6, 7
The medication can produce visible hair growth in up to 66% of men with mild to moderate alopecia, and importantly stops hair loss progression in 91% of patients. 8
Treatment should be initiated in men aged 18-60 years seeking medical treatment for androgenetic alopecia. 5
Key Points for Hair Loss Treatment
- Visible improvement typically begins by 12 weeks, with maximal benefit at 1-2 years 5
- Efficacy is maintained over 5+ years with continued treatment 5
- Hair loss resumes if treatment is discontinued 5, 8
- The 1 mg dose is optimal; doses below 0.5 mg/day produce insufficient DHT suppression, while doses above 5 mg/day provide little additional benefit 2
Important Limitation
Finasteride is NOT approved for the prevention of prostate cancer. 1 While the Prostate Cancer Prevention Trial showed a 25% reduction in prostate cancer period prevalence, concerns about increased detection of high-grade tumors and lack of mortality data led to this explicit FDA limitation. 4
Mechanism of Action Across Indications
Finasteride inhibits type 2 5α-reductase enzyme, which converts testosterone to dihydrotestosterone (DHT). 2, 6, 3
- In the prostate, DHT reduction leads to approximately 20% volume decrease 4, 2
- In hair follicles, DHT inhibition prevents miniaturization and promotes hair growth 6, 8
- A single 5 mg dose suppresses serum DHT levels for up to 4 days due to high enzyme affinity 2
Critical Monitoring Requirement for All Indications
PSA levels must be doubled after 12 months of finasteride therapy to accurately interpret prostate cancer screening results. 9, 5 Finasteride reduces PSA by approximately 50% regardless of dose (1 mg or 5 mg). 9, 5
Failure to adjust PSA values can lead to delayed cancer diagnosis and potentially worse outcomes. 9
Consider obtaining baseline PSA before starting finasteride in men approaching prostate cancer screening age (>40-45 years), even when treating hair loss. 5