---
title: Doubling the dose improved the flow rate and left the symptom score where it was
publication: Medical Insights Korea
section: news
category: Prostate
canonical_url: https://medicalinsightskorea.com/news/korea-bph-tamsulosin-dose-escalation-flow-versus-symptoms
author: Andrew Cho
published: 2026-10-26T09:00:00+09:00
modified: 2026-10-26T09:00:00+09:00
content_type: reporting
license: Quotation permitted with attribution to Medical Insights Korea and a link to the canonical URL.
---

# Doubling the dose improved the flow rate and left the symptom score where it was

Peak flow rose from 14.4 to 17.7 mL/s. IPSS did not move. The two numbers measure different things, and only one of them is what the patient came in about.

## Answer

In a retrospective review of 57 men treated at Seoul National University Bundang Hospital in 2022 whose symptoms responded inadequately to tamsulosin 0.2 mg, escalating to 0.4 mg raised the mean maximum urinary flow rate from 14.4 to 17.7 mL/s (P < 0.001) with consistent benefit across subgroups, while the International Prostate Symptom Score and postvoid residual volume showed no significant overall change — postvoid residual fell significantly only in men with prostates larger than 50 mL.

## Key takeaways

- 57 men at Seoul National University Bundang Hospital had their tamsulosin escalated from 0.2 mg to 0.4 mg in 2022 after an inadequate response to the lower dose.
- Mean maximum urinary flow rate rose from 14.4 to 17.7 mL/s (P < 0.001).
- The improvement in flow was consistent across subgroups of age, prostate volume and concomitant 5-alpha-reductase inhibitor use.
- The International Prostate Symptom Score showed no significant overall change.
- Postvoid residual volume showed no significant overall change either.
- Postvoid residual did fall significantly in the subgroup with prostate volume above 50 mL.
- The study was a retrospective single-centre review of 57 patients with no control group.

## Full article

Korea licenses tamsulosin at 0.2 mg, a dose lower than the 0.4 mg used in most Western trials, and the escalation from one to the other is a routine next step when symptoms persist. A Korean centre went back over what actually happened when it did that.

### One number moved and one did not

**14.4 → 17.7 mL/s** — mean maximum urinary flow rate after escalating tamsulosin from 0.2 mg to 0.4 mg in 57 Korean men (P < 0.001)  
_Source: Chung Y et al., Investigative and Clinical Urology, 2026_

A rise of 3.3 mL/s in peak flow is not trivial; it is the kind of change a urologist would call a response. Over the same period the International Prostate Symptom Score did not change significantly, and neither did postvoid residual volume except in men with a prostate over 50 mL.

### Why that combination is uncomfortable

> **Uroflowmetry is what the clinic sees; IPSS is what the man feels**  
> Peak flow is measured on a machine in a few seconds. The symptom score asks about the whole experience — urgency, frequency, getting up at night, the sense of not having emptied. A dose increase that improves the first and not the second has produced a better reading without producing a better life, and the reading is the one that will be recorded as evidence the escalation worked. This discordance is well known in lower urinary tract symptoms and it is usually mentioned in passing; here it is the entire result.

The generous interpretation is that 57 patients is too few to detect a modest symptom change, and that is likely part of it — the study had no control group and no correction for the improvement that follows any change in management. The less generous one is that flow rate and symptoms are only loosely coupled in benign prostatic hyperplasia, which is a long-standing finding rather than a surprise.

### Who it does look useful for

The postvoid residual signal in men with prostates above 50 mL is the most specific thing in the paper. A large gland with retained urine is the situation where mechanical obstruction is doing the work, and it is where more alpha-blockade would be expected to help. The authors' conclusion follows that reading: escalation is worth trying particularly in men with larger prostates or on concomitant 5-alpha-reductase inhibitor therapy.

What the study cannot support is escalating on the strength of a flow rate alone. If the dose goes up and the man reports no difference, the flow meter agreeing with the prescription is not evidence that he is better.

## Sources

- Chung Y, Jeong SJ, Song SH, Hong SK. The efficacy of tamsulosin 0.4 mg when tamsulosin 0.2 mg is insufficient for benign prostatic hyperplasia in Korean patients. Investigative and Clinical Urology 2026;67(2):186-191. doi:10.4111/icu.20250569. PMID:41775449. https://doi.org/10.4111/icu.20250569

## Citation

Andrew Cho (2026). "Doubling the dose improved the flow rate and left the symptom score where it was". Medical Insights Korea. https://medicalinsightskorea.com/news/korea-bph-tamsulosin-dose-escalation-flow-versus-symptoms

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