What is actually different?
This comparison often matters when a man has an enlarged prostate and is also thinking about erectile function, speed of symptom improvement or long-term prostate growth.
Finasteride is a 5-alpha-reductase inhibitor. In BPH treatment it is used when reducing DHT-driven prostate growth and lowering long-term progression risk are important treatment goals. It is not a rapid muscle-relaxing drug.
Tadalafil can be attractive when BPH and erectile dysfunction coexist, while finasteride may fit a different goal when prostate enlargement and progression risk are central.
Side-by-side decision table
| Factor | Finasteride | Tadalafil |
|---|---|---|
| Drug class | 5-alpha-reductase inhibitor | PDE5 inhibitor |
| Shrinks prostate | Can reduce enlarged prostate volume over time | Not its primary BPH action |
| PSA effect | Lowers PSA | Not expected to halve PSA |
| ED treatment | Not an ED treatment | Also indicated for erectile dysfunction |
| Speed | Gradual | Different onset profile |
| Blood-pressure interactions | Different profile | Important with nitrates and some BP drugs |
Speed, prostate size and symptom goals
One of the most important distinctions in BPH treatment is whether the goal is faster symptom relief, modification of prostate growth, treatment of erectile dysfunction, or some combination of these. A drug can be useful without doing all of those jobs.
Finasteride generally belongs to the slower, prostate-size-focused side of that decision. A clinician may therefore use prostate size, PSA, symptom pattern and progression risk when deciding whether it belongs in the treatment plan.
Sexual side-effect trade-offs
Finasteride prescribing information describes erectile dysfunction, decreased libido, reduced ejaculate volume and ejaculation disorder. That does not mean every sexual symptom during treatment is caused by finasteride. Age, vascular health, diabetes, mood, testosterone status, other medications and BPH itself can contribute.
If sexual function is an important treatment priority, compare the actual adverse-event profile of the alternatives rather than assuming that switching drug classes removes all sexual trade-offs.
PSA considerations
Finasteride can lower PSA substantially. Prescribing information notes that in older men treated with 5 mg for BPH, PSA levels are decreased by about 50%. A confirmed increase from the lowest PSA while taking finasteride deserves clinical evaluation even if the absolute value appears to fall within a conventional reference range.
Questions to discuss with your clinician
- What was the main reason finasteride was chosen for me: prostate size, progression risk, urinary symptoms, or a combination?
- How long should we give this treatment before deciding whether the benefit is adequate?
- How should my PSA be interpreted while I am taking finasteride, and what change would trigger further evaluation?
- If side effects or persistent symptoms are a problem, which alternatives preserve the benefits I still need?
Frequently asked questions
Does tadalafil shrink the prostate like finasteride?
No. Tadalafil can improve lower urinary tract symptoms but is not used as a prostate-shrinking 5-alpha-reductase inhibitor.
Can tadalafil and finasteride be used together?
They can be used together in selected situations, but the decision depends on symptoms, blood pressure, other medicines and treatment goals.
Which is more relevant when ED is also a concern?
Tadalafil is also indicated for erectile dysfunction. Finasteride is not an ED treatment and can cause sexual adverse effects in some users.
Which one changes PSA interpretation?
Finasteride does. Tadalafil does not have the same PSA-lowering effect associated with 5-alpha-reductase inhibition.
Should I stop finasteride if I think I have a side effect?
Do not stop a prescription medication solely on the basis of an online article. Contact the prescriber to review severity, timing, other possible causes and reasonable alternatives.
Can finasteride and tamsulosin be used together?
They can be prescribed together in selected men because they work differently. Whether combination therapy makes sense depends on prostate size, symptom burden, progression risk and tolerance.
Does finasteride shrink the prostate?
Finasteride is used in BPH partly because 5-alpha-reductase inhibition can reduce prostate growth and shrink enlarged prostate tissue over time.
Is finasteride appropriate for every man with BPH symptoms?
No. Treatment choice depends on symptom burden, prostate size, PSA, other conditions, current medicines, side-effect priorities and patient preferences.
Does finasteride treat prostate cancer?
Finasteride is not a treatment for prostate cancer. Because it changes PSA levels, prostate-cancer screening and PSA trends require appropriate clinical interpretation.
What should I tell my clinician before a PSA test?
Tell the clinician that you take finasteride, how long you have taken it and whether you have missed doses or recently stopped, because this can affect interpretation.
Can online symptom scores tell me which prescription drug to use?
No. They can help organize questions, but prescription selection requires clinical evaluation and should account for examination findings, medication history and other health factors.
When do urinary symptoms need urgent medical care?
Seek prompt care for inability to urinate, severe lower abdominal pain, fever with urinary symptoms, visible blood in urine, fainting or other severe symptoms.
Sources
Realvigor prioritizes U.S. prescribing information, public-health references and clinical guidelines. Source links open in a new tab.
Related finasteride decisions
Finasteride guide
Core BPH medication hub for mechanism, PSA effects, side effects and related decisions.
Tamsulosin vs Finasteride
Compare a fast symptom-relief alpha blocker with a prostate-shrinking 5-alpha-reductase inhibitor.
Finasteride sexual side effects
Review erectile, libido and ejaculation concerns with source-based context.
PSA while taking finasteride
Understand why PSA interpretation changes during finasteride treatment.
Finasteride not working
Research timeline, prostate size, symptom pattern and next questions when benefit seems limited.
Finasteride alternatives
Compare other medication classes and procedure pathways.