I previously took saw palmetto but still had to get up several times at night to urinate. After knee replacement surgery about three years ago, I developed urinary retention. A urologist started me on Flomax and later Avodart and advised me to stop saw palmetto. Since then I have lost about 35 lb, from approximately 180 lb, and have had dizziness, restlessness and weakness. Several tests have not found an obvious cause. Could Flomax or Avodart be responsible? Can I stop them and return to saw palmetto?
Quick Answer
Do not automatically stop both Flomax (tamsulosin) and Avodart (dutasteride) and replace them with saw palmetto.
- Tamsulosin can cause dizziness and orthostatic symptoms, especially when standing, and this deserves review if you feel weak, lightheaded or at risk of falling.
- A 35-lb unexplained weight loss is not a typical expected side effect of either medicine. It deserves continued medical evaluation rather than being assumed to come from BPH medication.
- Dutasteride does not primarily lower testosterone. It blocks conversion of testosterone to dihydrotestosterone (DHT).
- Dutasteride can reduce prostate volume and lower the long-term risk of urinary retention and BPH surgery in appropriately selected men.
- After months of combination treatment, some men may be able to stop tamsulosin while continuing dutasteride, but this should be decided with the prescribing doctor.
- Saw palmetto has not been shown reliably to replace tamsulosin or dutasteride.
Why Were Flomax and Avodart Prescribed Together?
These two medicines treat BPH in different ways.
| Medicine | How It Works | Main Role |
|---|---|---|
| Flomax (tamsulosin) | Blocks alpha-1 receptors and relaxes smooth muscle around the prostate and bladder outlet. | Can improve urine flow and urinary symptoms relatively quickly. |
| Avodart (dutasteride) | Inhibits type 1 and type 2 5-alpha-reductase, reducing conversion of testosterone to DHT. | Gradually reduces prostate volume and lowers progression risk in selected men with significant prostate enlargement. |
This combination is particularly appropriate in men with moderate-to-severe lower urinary tract symptoms and an increased risk of BPH progression.
Current EAU guidance gives prostate volume above approximately 40 mL as one example of increased progression risk.
Does Flomax Stop Working Because Your Body Gets Used to It?
The older answer on this page described a process of “down-regulation” and suggested doctors need to change the tamsulosin dose three or four times per year.
That is not standard BPH management.
Tamsulosin is not routinely cycled or repeatedly dose-adjusted simply to prevent the body from becoming accustomed to it.
If symptoms worsen despite treatment, the appropriate response is to reassess what is happening.
That may include checking:
- symptom severity;
- urine flow;
- post-void residual urine;
- prostate size;
- urinalysis;
- medication adherence;
- and whether another bladder or urinary condition is contributing.
Our prostate and urinary testing guide explains how these problems are evaluated.
Can Flomax Cause Dizziness and Weakness?
Yes, dizziness is a recognized adverse effect of tamsulosin.
Tamsulosin is more selective for urinary-tract alpha receptors than older alpha-blockers, but it can still cause:
- dizziness;
- postural or orthostatic hypotension;
- lightheadedness;
- and, less commonly, fainting.
The current Flomax prescribing information specifically warns that signs and symptoms of orthostasis occur more frequently with tamsulosin than placebo.
Falls Matter
If dizziness occurs when getting out of bed or standing from a chair, the prescribing clinician should review blood pressure, tamsulosin and all other medicines that may lower blood pressure. Recurrent falls or near-fainting should not simply be accepted as a normal price of BPH treatment.
Can Avodart Cause These Symptoms?
Dutasteride has a different adverse-effect profile.
The most commonly reported adverse effects include:
- erectile dysfunction;
- decreased libido;
- ejaculatory disorders;
- and breast enlargement or tenderness.
Depressed mood has also been reported after marketing.
Dizziness can occur, particularly when dutasteride is used together with tamsulosin, but it is much more characteristic of alpha-blocker treatment than of dutasteride alone.
Does Avodart Lower Testosterone?
Not in the way described in the old answer.
Dutasteride inhibits 5-alpha-reductase, the enzyme responsible for converting testosterone into the more potent androgen dihydrotestosterone (DHT).
It therefore markedly lowers DHT.
It should not be explained to patients as simply lowering all testosterone in the body.
That distinction matters because the benefits and side effects of 5-alpha-reductase inhibitors are related largely to suppression of DHT within prostate and other androgen-sensitive tissues.
Could Flomax or Avodart Explain a 35-lb Weight Loss?
I would not assume so.
A loss from approximately 180 lb to 145 lb represents nearly 20% of the original body weight.
That is clinically significant when it is unintentional.
Neither tamsulosin nor dutasteride routinely causes major progressive weight loss as a typical adverse effect.
Unexplained Weight Loss Needs Continued Evaluation
Even if previous scans and blood tests were reassuring, persistent unintentional weight loss deserves reassessment.
Possible causes extend well beyond prostate medication and can include:
- reduced food intake;
- gastrointestinal disease;
- thyroid disease;
- diabetes;
- chronic infection;
- depression;
- medication effects;
- neurological illness;
- and malignancy, among many other possibilities.
The fact that initial investigations were normal is reassuring, but it does not make a 35-lb unexplained loss something I would attribute automatically to Flomax or Avodart.
Can You Stop Flomax After Taking Avodart for Several Months?
Sometimes.
This is an important point because the two medicines work at different speeds.
Tamsulosin can begin improving symptoms relatively quickly. Dutasteride works much more slowly and may require months before its full clinical benefit is seen.
EAU cites studies examining withdrawal of the alpha-blocker after six to nine months of combination therapy.
In one randomized study of dutasteride plus tamsulosin, nearly three-quarters of men had no worsening of symptoms after tamsulosin was withdrawn at six months.
However, men whose symptoms were severe before treatment may benefit from continuing combination therapy longer.
This Is a Much Better Question to Ask the Doctor
Rather than: “Can I stop both drugs and use saw palmetto?”
ask: “Now that I have been on dutasteride for several years, do I still need tamsulosin, particularly given my dizziness?”
Should Avodart Also Be Stopped?
That depends much more on why it was prescribed.
Dutasteride is most useful when a man has a significantly enlarged prostate and an increased risk of progression.
EAU reports that after two to four years, 5-alpha-reductase inhibitors can:
- reduce prostate volume by approximately 18–28%;
- improve urinary symptom scores;
- increase maximum urine flow;
- reduce the risk of acute urinary retention;
- and reduce the likelihood of BPH surgery.
Therefore, stopping dutasteride in a man who continues to have a large prostate may remove some of the long-term protection that prompted treatment in the first place.
Review the broader evidence in our BPH medication guide .
Why Prostate Size Matters
The old answer used statements such as “six or seven times normal size” versus “two or three times normal size.”
That is not a useful way to make treatment decisions.
A better assessment considers:
- prostate volume in mL or cc;
- severity of urinary symptoms;
- PSA where appropriate;
- post-void residual urine;
- urine-flow rate;
- previous retention;
- age and overall health;
- and risk of progression.
If the prostate is small and obstruction is not clearly caused by BPH, a 5-alpha-reductase inhibitor may offer less benefit.
If the prostate is substantially enlarged, continuing dutasteride may be more important.
What Happens to PSA While Taking Avodart?
This is another important issue before stopping treatment.
Dutasteride typically lowers serum PSA by approximately 50% within three to six months.
Doctors therefore interpret PSA differently in men taking dutasteride and establish a new treatment baseline.
Any confirmed rise from the lowest PSA value while taking dutasteride deserves evaluation.
If dutasteride is stopped, tell every clinician interpreting future PSA results that you have previously been taking a 5-alpha-reductase inhibitor.
The medicine also has a long biological persistence, so its effects do not disappear immediately after the last capsule.
Can Saw Palmetto Replace Flomax or Avodart?
I would not recommend assuming that it can.
Saw palmetto (Serenoa repens) is widely marketed for urinary symptoms associated with BPH.
However, NCCIH’s current assessment says we now know enough to conclude that saw palmetto is probably not helpful for BPH symptoms.
A 2023 review of 27 studies concluded that saw palmetto used alone produced little or no benefit.
Two NIH-funded randomized trials also failed to show meaningful improvement, including one that tested substantially higher doses.
There are some conflicting studies involving specific extracts, which is why you may encounter more favorable claims online, but this evidence does not justify treating ordinary saw-palmetto supplements as equivalent to prescription BPH therapy.
Our updated natural remedies for enlarged prostate guide compares the available evidence.
| Treatment | Fast Symptom Relief? | Shrinks Prostate? | Reduces Retention/Surgery Risk? |
|---|---|---|---|
| Tamsulosin | Yes, often relatively quickly | No | Not proven to reduce long-term progression on its own |
| Dutasteride | Slow onset | Yes, in appropriate enlarged prostates | Yes |
| Tamsulosin + dutasteride | Yes | Yes, due to dutasteride | Strong evidence in higher-risk men |
| Saw palmetto | Uncertain | Not reliably demonstrated | Not established |
What About Kegel Exercises?
The old answer recommended Kegel exercises to stimulate the effects of tamsulosin and dutasteride.
That should also be corrected.
Pelvic-floor exercises can be valuable for specific problems such as urinary incontinence, especially after prostate surgery.
But Kegel exercises do not amplify the pharmacological effect of tamsulosin or dutasteride and do not shrink BPH.
In some men with a tight or overactive pelvic floor, repeatedly contracting the pelvic muscles may even be the wrong approach.
What Should Be Reviewed Before Changing Treatment?
Before deciding what to discontinue, I would want to know:
- Current prostate volume. Was the prostate actually enlarged when dutasteride was started?
- Current urinary symptoms. How often do you urinate, how strong is the stream, and how often do you wake at night?
- Post-void residual. Are you emptying your bladder adequately now?
- History of urinary retention. The inability to urinate after surgery may have been temporary postoperative retention, or it may have revealed significant pre-existing obstruction.
- Blood pressure lying/sitting and standing. This is particularly important because of the dizziness.
- All other medicines. Blood-pressure medicines, diuretics, PDE5 inhibitors and several other drugs can contribute to dizziness.
- The unexplained weight loss. This needs to be considered separately rather than attributed automatically to BPH medication.
- Current PSA and previous PSA values. These must be interpreted in the context of dutasteride use.
Dr. Albana’s Answer
Hello,
I understand why you are questioning your treatment, particularly because you have experienced dizziness, weakness and a substantial amount of unexplained weight loss.
I would first separate these issues.
Your dizziness could plausibly be related to Flomax. Tamsulosin can cause orthostatic dizziness and occasionally fainting, especially when standing, and this deserves review.
However, I would not assume that losing 35 lb is caused by Flomax or Avodart. That degree of unintentional weight loss is clinically important and should continue to be investigated even if previous tests have not identified an obvious explanation.
I would also correct some of the previous information on this page. Flomax does not normally have to be changed several times a year because your receptors become accustomed to it.
Avodart also does not simply lower your testosterone. Dutasteride mainly blocks the conversion of testosterone into DHT, which is an important driver of prostate growth.
After three years of combination treatment, however, it is reasonable to ask whether you still need both medicines.
In selected men who have taken dutasteride and tamsulosin together for at least six months, the tamsulosin can sometimes be discontinued without substantial worsening of urinary symptoms. Men who started with severe symptoms may still need both.
I would therefore ask your urologist to reassess your prostate size, symptom score, urine flow, residual urine and blood pressure.
If dizziness appears to be related to tamsulosin and your urinary situation is stable after several years of dutasteride, your doctor may consider a supervised trial without tamsulosin.
I would not automatically stop dutasteride at the same time. If you have a significantly enlarged prostate, dutasteride may still be reducing the risk of future urinary retention and surgery.
And I would not replace these medicines automatically with saw palmetto. Current evidence does not show that ordinary saw-palmetto supplements provide the same symptom control or long-term protection as established BPH medicines.
The safest approach is therefore not “stop everything and return to herbs,” but rather: identify which medicine is still necessary, which one may be contributing to symptoms, and whether the original reason for combination therapy is still present.
— Dr. Albana Greca, MD, MMedSc, Family Physician / General Practitioner
Seek Prompt Medical Attention If
- you faint or repeatedly nearly faint;
- you develop chest pain or shortness of breath;
- you cannot urinate at all;
- you develop severe lower abdominal pain;
- you have visible blood in the urine;
- weakness is rapidly worsening;
- or unexplained weight loss continues.
Most Asked Questions
Can I suddenly stop Flomax?
Tamsulosin does not usually require tapering for drug withdrawal, but stopping it can allow urinary symptoms or retention to recur. Discuss the change with your prescriber, especially if you have previously had urinary retention.
Can I stop Flomax but continue Avodart?
Sometimes. Studies have shown that some men remain stable after tamsulosin is withdrawn following several months of combination treatment. Baseline symptom severity and current urinary function matter.
Does Flomax cause dizziness?
Yes. Dizziness and orthostatic symptoms are recognized adverse effects of tamsulosin.
Does Avodart cause major weight loss?
Major weight loss is not a typical common adverse effect of dutasteride. Significant unexplained weight loss should be evaluated separately.
Does Avodart lower testosterone?
Dutasteride primarily reduces DHT by blocking conversion of testosterone through 5-alpha-reductase. It should not simply be described as lowering all testosterone.
Can saw palmetto replace dutasteride?
There is no good evidence that saw palmetto provides dutasteride’s established prostate-volume reduction or protection against BPH progression.
Can saw palmetto replace Flomax?
Current evidence does not reliably show that saw palmetto provides equivalent symptom relief to tamsulosin in ordinary clinical use.
Does Avodart affect PSA?
Yes. Dutasteride typically lowers PSA by about 50% within three to six months, so PSA results must be interpreted differently while taking it.
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 -
U.S. National Library of Medicine, DailyMed.
Flomax (tamsulosin hydrochloride) Prescribing Information.
DailyMed Flomax -
U.S. National Library of Medicine, DailyMed.
Avodart (dutasteride) Prescribing Information.
DailyMed Avodart -
National Center for Complementary and Integrative Health.
Saw Palmetto: Usefulness and Safety.
NCCIH Saw Palmetto -
National Center for Complementary and Integrative Health.
Benign Prostatic Hyperplasia and Complementary and Integrative Approaches.
NCCIH BPH Evidence Review
Medical information notice: Do not change prescription BPH medicines solely on the basis of information on this page. Medication withdrawal should take account of prostate size, urinary symptoms, previous urinary retention, post-void residual, blood pressure and the reason the medicines were originally prescribed.
Written & medically reviewed by Dr. Albana Greca, MD, MMedSc • Family Physician / General Practitioner • Last medically reviewed: August 2026