前列腺肥大症药物：两种药物的原理以及它们对你的成本

最后更新: 2026年8月27日

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Benign prostatic enlargement becomes commoner with every decade — affecting roughly four men in ten in their fifties, more than seven in ten in their sixties, and the large majority by their eighties. It is not dangerous in itself, and it is not something every man needs treating: plenty of men have an enlarged prostate and symptoms mild enough to live with comfortably.

For those who do want treatment, two classes of tablet are used, and they do entirely different things. For the condition itself see 前列腺肥大 — the link on this page previously pointed to an address that no longer exists.

• 泰国曼谷医院泌尿外科中心 在线预约 02-310-3009 bhquro@bdms.co.th
• Samitivej Sriracha Hospital 春武里府 088-022-1445

Alpha-blockers: fast, and they do not shrink anything

These relax the smooth muscle of the prostate and bladder neck, widening the channel. They work within days, and are the usual first choice.

They do not change the prostate or slow the condition — stop the tablet and the symptoms return. That is not a criticism; for many men it is exactly what is wanted.

What they do to you

• Dizziness and light-headedness on standing, since they lower blood pressure. Worst in the first days and in older men, which is why the first dose is usually taken at night.
• Reduced or absent ejaculation. The earlier version mentioned abnormal ejaculation in passing without saying what that means. It means the volume falls, sometimes to nothing at all. It is harmless, it reverses on stopping, and men who are not warned about it often stop the tablet believing something has gone badly wrong. It is commoner with some drugs in the class than others, so it is worth raising rather than enduring — switching frequently solves it.
• They do not cause erectile dysfunction — worth stating plainly, since men frequently assume otherwise and blame the tablet.
• Added to a PDE5 inhibitor for erections, blood pressure can drop more than either drug would cause alone. Tell whoever prescribes either that you take the other.

Tell your eye surgeon — even years later

This was absent from the earlier version and is the single most useful practical point about the class.

Alpha-blockers change the behaviour of the iris during cataract surgery, and the effect persists long after the tablet has been stopped. Forewarned, the surgeon adjusts the technique and the operation proceeds normally; taken by surprise mid-operation, it is a genuine problem. Anyone who has ever taken one should mention it before any eye operation, however long ago it was.

5-alpha reductase inhibitors: slow, and only if the prostate is large

These block the conversion of testosterone to dihydrotestosterone, the androgen that drives prostatic growth. Over about six months the prostate shrinks by up to roughly a third, and — unlike the alpha-blockers — they genuinely change the course of the condition, reducing the risk of ending up in retention or needing an operation.

One qualification matters more than anything else here and was not stated in the earlier version: they only work if the prostate is actually enlarged. In a man with a small prostate and troublesome symptoms, adding one produces the side effects without the benefit. Prostate size, measured or estimated, is what decides whether this drug belongs in the plan — not symptom severity.

The PSA point every man on one of these needs

The earlier version gave the fact — these drugs halve the PSA — without the instruction that goes with it.

After about six months on treatment, double your PSA result to interpret it. A reading of 2 in a man on one of these drugs behaves like a 4 in a man who is not. And tell whoever orders the test that you take it — a man on finasteride or dutasteride with a PSA that looks comfortably normal may not be comfortably normal at all, and this is one of the recognised routes to a delayed prostate cancer diagnosis.

What matters even more than the doubling is the direction: a PSA that rises while on one of these drugs is abnormal and needs investigating, whatever the absolute number looks like. See what a raised PSA means.

What they do to you

• Reduced sex drive, erectile difficulty, and reduced ejaculate volume, in a minority. These usually settle or reverse on stopping.
• 乳房的敏感性或增大, uncommon.
• Persistent sexual symptoms and low mood have been reported in some men after stopping, and are the subject of ongoing debate rather than settled fact. The honest position is that it is uncertain, uncommon, and worth knowing about before starting a drug that is taken for years — particularly by a younger man taking it for hair loss rather than for a prostate.
• Women who are or may become pregnant must not handle broken or crushed tablets, because of the effect on a male fetus. Intact tablets are coated for this reason.

Using both together

The two are complementary: one gives relief within days but changes nothing underlying, the other changes the course but takes half a year. Combined, they outperform either alone in men with a genuinely enlarged prostate and more than mild symptoms — and that qualification is the whole point. The earlier version described combination therapy as preferred for moderate-to-severe symptoms generally, which is too broad: in a man whose prostate is not large, it means two sets of side effects for the benefit of one drug.

Two further honest points. It is treatment taken indefinitely — stopping returns things to baseline. And some men, told they face two tablets a day for the rest of their lives, would rather have a one-off procedure instead. That is a legitimate preference and worth raising rather than assuming tablets are the default.

It is also worth knowing that a poor stream is not always the prostate. A 尿道狭窄 produces identical symptoms, and a bladder that has become underactive will not improve with prostate medication at all — which is what 流测试 helps to sort out.

Symptoms that need attention rather than a repeat prescription

在泰国遇到紧急情况时,请拨打 1669.

• 完全无法排尿 with a painful full bladder — same-day treatment.
• 发烧伴有下背部或排尿时疼痛。.
• 血尿, which needs investigating rather than attributing to the prostate.
• A PSA that is rising while on a 5-alpha reductase inhibitor.
• New bone pain or unexplained weight loss.
• Symptoms that came on over weeks rather than years, or in a man under about fifty.

Frequently Asked Questions About BPH Medication

How quickly does each drug work?

An alpha-blocker improves the stream within days. A 5-alpha reductase inhibitor takes around six months to shrink the prostate meaningfully, and its benefit in reducing retention and surgery builds over years of continued use.

I take finasteride or dutasteride. What about my PSA?

After about six months these drugs roughly halve the PSA, so double the result to interpret it and tell whoever orders the test that you take one. More important than the number is the trend — a PSA rising while on one of these drugs is abnormal and needs investigating regardless of how normal it looks.

Should everyone with BPH be on both drugs?

No. Combination therapy outperforms either drug alone in men with a genuinely enlarged prostate and more than mild symptoms. Where the prostate is not large, adding a 5-alpha reductase inhibitor gives the side effects without the benefit. Prostate size decides, not symptom severity.

My ejaculate has disappeared since starting the tablet. Is that serious?

No — it is a recognised effect of alpha-blockers, harmless, and reverses on stopping. It is commoner with some drugs in the class than others, so raise it rather than enduring it or stopping treatment on your own; switching often resolves it.

Do alpha-blockers cause erectile dysfunction?

No, and this is often assumed. They affect ejaculation, not erections. 5-alpha reductase inhibitors can affect desire and erections in a minority. If you take a tablet for erections as well, be aware that combining it with an alpha-blocker can lower blood pressure more than either alone.

Do I have to take these forever?

They work only while taken, and stopping returns symptoms to baseline. Some men prefer a one-off procedure to indefinite medication, which is a reasonable preference and worth discussing rather than assuming tablets are the default.

预约咨询

Dr. Soarawee Weerasopone 的出诊地点: Bangkok Hospital Headquarters 以及在春武里府的 Samitivej Sriracha Hospital,时间为 088-022-1445. Bring every previous PSA result with its date and a list of your medicines — including anything taken for hair loss, which is the same drug class and affects the PSA identically.

无法亲自就诊的患者(包括国际患者)可使用曼谷医院远程医疗服务——请提前通过电子邮件联系泌尿外科安排,邮箱: bhquro@bdms.co.th. 三美泰是拉差医院（Samitivej Sriracha）仅提供线下就诊服务。有关费用事宜，请直接向医院咨询，本网站不予解答。.

免责声明: 本内容由 Bangkok Hospital Headquarters 的委员会认证泌尿外科医生 Dr. Soarawee Weerasopone 撰写并审核,仅供健康教育之用。本内容不构成针对任何个人的医疗建议、诊断或处方,也不会通过私人消息渠道或社交媒体提供任何建议、诊断或处方。Dr. Soarawee 未开设任何公开社交媒体账号;任何以他的名义提供私人咨询的账号均为欺诈账号。在泰国遇到紧急情况时,请拨打 1669.