Finasteride vs Alprostadil: side-by-side comparison
Finasteride (5-alpha-reductase inhibitor (type II)) and Alprostadil (Prostaglandin E1 (PGE1)) belong to different therapeutic classes and are rarely substitutes for each other. The comparison is useful when a single patient is weighing both options for adjacent or overlapping needs.
| Property | Finasteride | Alprostadil |
|---|---|---|
| Therapeutic class | 5-alpha-reductase inhibitor (type II) | Prostaglandin E1 (PGE1) |
| CAS | 98319-26-7 | 745-65-3 |
| ATC | G04CB01 | G04BE01 |
| Molecular weight | 372.5 g/mol | 354.49 g/mol |
| Brands with this active ingredient | 1 | 1 |
What they share
Finasteride and Alprostadil share the common regulatory framework for prescription active ingredients, bioequivalence standards for generics, and pharmacist oversight. Beyond that, points in common are limited.
Key differences
Finasteride acts by a different mechanism than Alprostadil, with indications that barely overlap. Comparing the two is useful when a clinician has mentioned both in the same context or the patient wants to understand why one was prescribed instead of the other.
Mechanisms compared
Finasteride: Finasteride binds with high affinity to 5-alpha-reductase type II, blocking the conversion of testosterone into DHT. Alprostadil: Alprostadil binds prostaglandin E receptors on smooth muscle of the corpus cavernosum, triggering cAMP-mediated relaxation of cavernosal smooth muscle independent of the nitric oxide pathway used by PDE5 inhibitors.
Indications compared
Finasteride: Finasteride is approved at 5mg per day for the treatment of benign prostatic hyperplasia in adult men, where it reduces prostate volume, improves urinary flow and reduces the risk of acute urinary retention and need for… Alprostadil: Alprostadil is approved for erectile dysfunction of vasculogenic, neurogenic, psychogenic or mixed aetiology in adult men.
Safety profile
Finasteride: Common adverse effects include sexual side effects (decreased libido, erectile dysfunction, ejaculation disorders) reported in approximately 1-3% of men in clinical trials. Alprostadil: Common adverse effects include penile pain (most common with intracavernosal injection), hypotension, dizziness, urethral burning (with Muse), priapism (rare but serious), penile fibrosis with prolonged use, and small ri…
Frequently asked questions
Is Finasteride better than Alprostadil? ▾
Finasteride and Alprostadil are not "better or worse" — they treat different things. The sensible question is which fits your specific need.
Can Finasteride and Alprostadil be combined? ▾
Whether they can be combined depends on the indications and the interaction profile of each. If both are in a single prescription, the prescriber has weighed it; in self-medication they should never be combined.
Do they have the same side-effect profile? ▾
No — they belong to different classes and have distinct side-effect profiles. Each has its own prescribing information.
Products with Finasteride
Products with Alprostadil
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.