He is currently taking finasteride 5 mg for an enlarged prostate but is experiencing dizziness, lightheadedness and a feeling of being spaced out or disconnected. Could finasteride be responsible, and is there a natural alternative?
Quick Answer: Can Finasteride 5 mg Cause Low Blood Pressure or Dizziness?
Finasteride 5 mg is an established long-term BPH medicine, but low blood pressure is not one of its typical major effects. Dizziness and lightheadedness should still be taken seriously and evaluated rather than automatically blamed on—or excluded as being caused by—the drug.
- Finasteride reduces dihydrotestosterone (DHT); it does not stop the body from producing testosterone.
- It can gradually reduce prostate volume and lower the long-term risks of urinary retention and BPH-related surgery.
- Its better-established adverse effects include erectile dysfunction, reduced libido, reduced ejaculate volume and breast tenderness or enlargement.
- Dizziness and orthostatic hypotension are much more characteristic of alpha-blockers such as doxazosin, terazosin and, to a lesser degree, tamsulosin.
- If dizziness started after a medication change, every prescription, over-the-counter medicine and supplement should be reviewed.
- Do not replace finasteride with an unproven natural remedy without first determining whether finasteride is still medically appropriate.
What Is Finasteride 5 mg?
Finasteride 5 mg is a prescription 5-alpha-reductase inhibitor used to treat symptomatic benign prostatic hyperplasia in men with an enlarged prostate.
It is one of the main classes of BPH medications .
Unlike alpha-blockers, which can improve urinary symptoms relatively quickly by relaxing smooth muscle, finasteride works gradually by changing the hormonal environment within prostate tissue.
How Does Finasteride Work?
The old explanation on this page needs correcting.
Finasteride does not inhibit testosterone synthesis.
Instead, it blocks type 2 5-alpha-reductase, an enzyme that converts testosterone into dihydrotestosterone (DHT).
DHT is an important androgen within prostate tissue.
Lowering DHT gradually causes prostate epithelial tissue to shrink. Current EAU guidance reports that treatment for two to four years can:
- reduce prostate volume by about 18–28%;
- improve urinary symptom scores by about 15–30%;
- modestly improve maximum urine flow;
- and reduce the risk of acute urinary retention and BPH surgery.
This makes finasteride one of the medications that can genuinely reduce enlarged prostate tissue , rather than simply relaxing the prostate.
Does Finasteride Lower Blood Pressure?
Finasteride is not primarily a blood-pressure-lowering medicine.
Its usual mechanism does not relax blood vessels in the way alpha-blockers do.
By comparison, the alpha-blocker class commonly used for enlarged prostate includes medicines such as:
- tamsulosin;
- alfuzosin;
- doxazosin;
- terazosin;
- and silodosin.
EAU identifies dizziness and orthostatic hypotension among the most frequent adverse effects of alpha-blockers, with blood-pressure effects particularly prominent with doxazosin and terazosin.
Check the Entire Medication List
A man described as taking “finasteride” may also be using an alpha-blocker, antihypertensive medicine, diuretic, nitrate, erectile-dysfunction medicine or another drug that can contribute to dizziness or low blood pressure.
So What Could Cause the Dizziness and “Spaced-Out” Feeling?
Those symptoms should not be diagnosed from the symptom description alone.
Possible explanations include:
- orthostatic hypotension;
- another medication or medication interaction;
- dehydration;
- anemia;
- low blood glucose;
- infection or illness;
- heart-rate or rhythm abnormalities;
- blood-pressure problems;
- vestibular disorders;
- or neurological causes.
The timing is important. A clinician should know whether symptoms began:
- before or after finasteride was started;
- after adding another medication;
- mainly when standing;
- after meals;
- during exertion;
- or randomly.
Seek Prompt Care for Serious Symptoms
Dizziness accompanied by fainting, chest pain, new shortness of breath, severe headache, weakness on one side, trouble speaking, confusion or persistent neurological symptoms requires urgent medical assessment.
Repeated near-fainting or actual falls also deserves prompt evaluation.
Finasteride Plus an Alpha-Blocker Changes the Picture
Many men with BPH take finasteride together with an alpha-blocker because the two medicines work differently.
The alpha-blocker provides faster symptom relief, while finasteride acts slowly to reduce prostate size and progression risk.
In the long-term MTOPS study, symptoms such as dizziness and postural hypotension occurred more often with the finasteride-plus-doxazosin combination than with either treatment alone.
Therefore, if Robin’s friend is taking another prostate medicine in addition to finasteride, the exact name matters.
The same issue is important with combination products such as the tamsulosin/dutasteride medication discussed in our Tamdura side-effects guide .
What Are the Established Side Effects of Finasteride 5 mg?
The best-established adverse effects involve sexual function and breast symptoms.
| Possible Effect | What It Means | What to Do |
|---|---|---|
| Erectile dysfunction | Difficulty obtaining or maintaining an erection. | Discuss if persistent or troublesome. |
| Reduced libido | Lower sexual desire. | Review medication benefit versus adverse effects. |
| Reduced ejaculate volume | Less semen released during ejaculation. | Usually not dangerous, but may affect quality of life. |
| Ejaculatory dysfunction | Changes in ejaculation can occur. | Discuss if bothersome. |
| Breast enlargement or tenderness | Gynecomastia or nipple/breast discomfort. | Report persistent changes to a clinician. |
| Rash or hypersensitivity | Uncommon allergic-type reactions can occur. | Seek medical advice; urgent care for severe reactions. |
Current EAU guidance estimates gynecomastia with 5-alpha-reductase inhibitors in approximately 1–2% of patients.
What About Depression or Mood Changes?
Mood symptoms should not be ignored.
Current EAU guidance notes evidence suggesting an association between 5-alpha-reductase inhibitors and depression in some observational data, although research has not been completely consistent.
European regulators have also strengthened warnings concerning depressed mood, depression and suicidal thoughts with finasteride.
New Severe Mood Symptoms Need Medical Attention
If someone taking finasteride develops significant depression, behavioral changes or suicidal thoughts, seek medical advice promptly. Suicidal thoughts require urgent help.
Finasteride Has an Important Effect on PSA
Finasteride typically lowers serum PSA by approximately 50% after six to twelve months.
That reduction is expected and does not mean that PSA monitoring becomes unnecessary.
EAU recommends establishing a new baseline PSA after treatment has been underway and investigating a confirmed increase during follow-up when prostate-cancer diagnosis would affect management.
Our PSA guide explains how 5-alpha-reductase inhibitors change PSA interpretation.
Who Benefits Most From Finasteride?
Finasteride is not equally useful for every man with urinary symptoms.
EAU recommends 5-alpha-reductase inhibitors particularly for men who have:
- moderate-to-severe lower urinary tract symptoms;
- an enlarged prostate;
- and increased risk of BPH progression.
A prostate volume above roughly 40 mL is one example of increased progression risk used in current guidance.
Finasteride is less likely to provide meaningful benefit when the prostate is relatively small.
This is why appropriate prostate and urinary evaluation matters before deciding whether long-term medication is worthwhile.
Should Finasteride Be Replaced With a Natural Remedy?
Not automatically.
If finasteride is causing unacceptable adverse effects, the correct next step is to reassess:
- whether finasteride is actually causing the symptom;
- whether the patient still needs a 5-alpha-reductase inhibitor;
- prostate size and progression risk;
- the severity of urinary symptoms;
- other medications;
- and available alternatives.
Current evidence does not show that garlic, saw palmetto, pygeum, bee pollen or another supplement reliably reproduces finasteride’s proven effect on prostate volume and long-term progression risk.
Our review of natural remedies for enlarged prostate separates approaches with some clinical evidence from unsupported cure claims.
Lifestyle Measures Can Still Be Useful
Lifestyle measures may help certain urinary symptoms, but they should complement—not automatically replace—appropriate BPH medication when a man has substantial prostate enlargement or a significant progression risk.
Is Blood Pressure Below 120/80 Automatically Too Low?
No.
The old article incorrectly implied that values below 120/80 mmHg should be treated as abnormal.
A blood pressure below 120/80 can be completely normal.
What matters is the actual reading, symptoms, the patient’s usual blood pressure and whether pressure falls abnormally after standing.
Clinicians may check for orthostatic hypotension by measuring blood pressure after lying or sitting and again after standing.
Do Not Treat a Number With Coffee or Salt Without Knowing the Cause
Increasing caffeine, salt or fluid can be inappropriate in people with heart failure, kidney disease, hypertension or other medical conditions. The cause of symptomatic hypotension should be identified first.
Should Blood Pressure Be Checked Every Hour?
Usually not.
Hourly home monitoring is generally unnecessary unless a clinician has specifically requested it for a particular medical reason.
Repeated measurements can also become misleading if technique, positioning and timing are inconsistent.
More useful information may include:
- a properly measured seated blood pressure;
- a standing measurement when orthostatic symptoms occur;
- heart rate;
- timing of symptoms in relation to medication;
- and a complete medication list.
Should Someone Exercise During a Dizzy Episode?
No.
Push-ups or weight lifting are not appropriate acute treatment for a person who feels faint or markedly lightheaded.
Exercising while presyncopal can increase the risk of falling or injury.
If dizziness occurs, it is safer to sit or lie down, avoid driving or dangerous activity, and determine whether medical evaluation is needed.
What Should Robin Do Next?
I would approach this systematically.
- Do not stop finasteride abruptly without discussing it with the prescriber.
- Write down every prescription medicine, OTC medicine and supplement.
- Check whether an alpha-blocker or blood-pressure medicine is also being taken.
- Measure blood pressure correctly when symptomatic and, if safe, compare sitting and standing readings.
- Note whether symptoms began after finasteride or another medicine was introduced.
- Arrange clinical review if dizziness is persistent, recurrent or interfering with normal activities.
- Reassess whether finasteride remains appropriate based on prostate size, urinary symptoms and risk of BPH progression.
If BPH remains troublesome despite medication—or medication adverse effects become unacceptable—the broader BPH treatment options can be reviewed, including alternative medicines and selected procedures.
Dr. Albana’s Answer
Hello Robin,
Finasteride 5 mg is a well-established medicine for men with an enlarged prostate who are likely to benefit from reducing prostate size and lowering the future risk of urinary retention or surgery.
I would correct one important point from the older answer: finasteride does not stop testosterone production. It blocks the conversion of testosterone to DHT, which gradually reduces stimulation of prostate tissue.
I also would not tell you with certainty that finasteride cannot be related to the symptoms simply because low blood pressure is not one of its classic effects.
Dizziness, lightheadedness and feeling disconnected need to be assessed in context. If he is also taking an alpha-blocker such as tamsulosin, doxazosin or terazosin, or medicines for high blood pressure, those are particularly important to review because they can contribute to orthostatic hypotension.
I would not recommend measuring his pressure every hour, treating any reading below 120/80 as dangerous, giving coffee specifically to raise blood pressure, or doing push-ups while he feels lightheaded.
Instead, document the symptoms, blood-pressure readings and medicines and have his clinician determine whether he has true hypotension or another cause of the dizziness.
Regarding natural remedies, I would not replace finasteride with a supplement simply because it is described as natural. Finasteride has evidence for shrinking enlarged prostate tissue and reducing progression risk; most supplements do not have equivalent evidence.
If finasteride’s benefits no longer outweigh its adverse effects, his physician or urologist can discuss another medication strategy or another form of BPH treatment.
— Dr. Albana Greca, MD, MMedSc, Family Physician / General Practitioner
Most Asked Questions About Finasteride 5 mg
Does finasteride 5 mg lower blood pressure?
Finasteride is not primarily a blood-pressure-lowering medicine. Orthostatic hypotension is much more characteristic of alpha-blockers such as doxazosin or terazosin.
Can finasteride cause dizziness?
Dizziness should not automatically be attributed to finasteride, but it should not be dismissed either. Other medicines, dehydration, orthostatic hypotension and medical conditions should be reviewed.
Does finasteride reduce testosterone?
Finasteride blocks conversion of testosterone to DHT rather than directly stopping testosterone production.
Does finasteride shrink an enlarged prostate?
Yes. Long-term 5-alpha-reductase inhibitor treatment can reduce prostate volume by approximately 18–28% in appropriately selected men.
How long does finasteride take to work for BPH?
It works slowly. Clinical effects generally require several months, which is why finasteride is intended mainly for long-term treatment.
What are the common sexual side effects?
Erectile dysfunction, decreased libido, reduced ejaculate volume and less commonly other ejaculation changes can occur.
Does finasteride change PSA?
Yes. It commonly reduces PSA by approximately 50% after six to twelve months, so doctors must account for finasteride when interpreting PSA results.
Can I replace finasteride with saw palmetto or another herb?
Herbal products do not have equivalent evidence for reducing prostate size and preventing BPH progression. Any switch should be discussed with the treating clinician.
Is blood pressure of 110/70 too low?
Not necessarily. Some healthy people normally have readings around that level. Symptoms, usual blood pressure, medications and changes on standing are more important than treating one number in isolation.
Related BPH Medication Guides
Medical References
-
European Association of Urology.
EAU Guidelines on the Management of Non-neurogenic Male Lower
Urinary Tract Symptoms — Disease Management.
2026.
EAU Male LUTS Guideline -
European Association of Urology.
EAU Male LUTS Guidelines — Follow-up.
2026.
EAU Follow-up Guidance -
DailyMed / Organon.
PROSCAR (finasteride) 5 mg Prescribing Information.
Revised March 2026.
DailyMed Proscar Prescribing Information -
National Institute of Diabetes and Digestive and Kidney Diseases.
Urinary Retention Treatment.
NIDDK
Medical information notice: Dizziness and low blood pressure have many possible causes. Do not stop finasteride, change blood-pressure medication, increase salt or caffeine, or substitute supplements without appropriate medical advice.
Written & medically reviewed by Dr. Albana Greca, MD, MMedSc • Family Physician / General Practitioner • Last medically reviewed: August 2026