3 Reasons Why the Diuretic You Are Taking Is Not Controlling Your Blood Pressure

If you're diuretics are not effectively lowering your blood pressure, there could be something else going on.

October 27, 2023

We are fortunate to have dozens of medications that can help lower high blood pressure (BP). Diuretics are one of these common medications. They work by increasing the amount of sodium excreted by the kidneys. Diuretics are prescribed to millions of people with high blood pressure and do a pretty good job of bringing high blood pressure under control.

But for many who are taking diuretics, they fail to control their blood pressure adequately.

In this article, I’ll discuss the top 3 reasons why diuretics fail to reduce hypertension.

Reason #1:

The Hypertension is not “salt-sensitive”


In many people, hypertension is “salt-sensitive.” In simple terms, this means that the high blood pressure they experience comes from the excess sodium (salt) being retained by the kidneys.

The genetic tendency of the kidneys to hold onto sodium was actually a gift of evolution that helped prevent dehydration, particularly in those living in tropical climates and consuming a natural low-salt diet.

However, today, most of us ingest way more salt than we actually need. Restaurants, processed foods, and added salt contribute to better-tasting food at the expense of our health. If you are genetically programmed to retain extra sodium, your blood pressure increases and you end up with salt-sensitive hypertension.

On the contrary, if your hypertension is not salt-sensitive and is caused by other mechanisms, diuretics won’t work for you.


How can you tell if your high blood pressure is "salt sensitive"?

  1. 2 easy ways to tell if you are salt-sensitive or not is if you retain fluid and experience high blood pressure when your salt intake is high.
  2. Another is a blood test that measures the activity of the enzyme renin. Although few physicians order this test, a low value strongly suggests salt-sensitive hypertension.
  3. Race and age are two other indicators. Salt-sensitive hypertension is more common among black people than other races and it is more common in older populations. Among young adults, about 25% of white patients and 50% of black patients have salt-sensitive hypertension. Those percentages increase with age in both populations because of the decline in kidney function.

Reason #2:

Your diuretic dosing is too low

Today, the most commonly prescribed diuretic is hydrochlorothiazide (HCTZ). Doctors usually prescribe 25 mg, once daily. For many, this dosage is simply too low.

Studies show that treatment with most types of blood pressure medications lowers systolic BP, on average, by about 12 mm. On the other hand, 25 mg of HCTZ lowers it, by only 7 mm on average; a 50 mg dose will lower it by 12 mm.

Many doctors are hesitant to increase the dose even if the patient's blood pressure is still high because higher doses are more likely to result in adverse metabolic effects such as low blood potassium levels.

Instead, doctors add other medications that lower blood pressure by other mechanisms. This works if your hypertension is at least partly due to mechanisms other than salt sensitivity. But if salt sensitivity is the primary driver of your hypertension, those medications will not bring your blood pressure under control.

An alternative option is to take a slightly higher dose of HCTZ at 37.5 mg, which is a pill and a half. A much better option is to add a low dose of a second diuretic, in particular, a diuretic that reduces the loss of potassium.

There are  3 diuretics to choose from:

Amiloride is my favorite because it is better tolerated than spironolactone, and much less expensive than eplerenone.

If you experience periodic spikes in your blood pressure after consuming salty foods, there is another diuretic dosing method I recommend to patients. You should check it out.

Reason #3:

You're salt sensitive + another reason

If you have high blood pressure, it is usually caused by any or all of the three mechanisms. Controlling your blood pressure requires addressing the mechanisms causing your hypertension. I cover this extensively in my book: Hypertension and You; Old Drugs, New Drugs and the Right Drugs for Your High Blood Pressure

Two of the mechanisms are related to kidney function. One is salt sensitivity, which responds best to either a diuretic or a calcium channel blocker. The second is the renin-angiotensin hormonal system, which responds best to an angiotensin-converting enzyme inhibitor (ACE inhibitor) such as lisinopril or enalapril, or to an angiotensin-receptor blocker (ARB) like valsartan and losartan.

Hypertension can be controlled in 80% or more of patients with medication that targets either or both of these two mechanisms.


The third mechanism, which is often not considered by doctors, is the sympathetic nervous system (SNS). The SNS drives our fight-or-flight reflex when we encounter emotional distress or danger. 

Decades of mind/body research have not been able to prove that the stress or emotional distress we experience causes hypertension, or that stress reduction techniques can cure or alleviate it. In fact, the cause of the increase in SNS tone has remained a mystery.

In my recent book, Hidden Within Us; a Radical New Understanding of the Mind-Body Connection, I bring attention to the important, yet almost completely unrecognized role of the powerful emotions that we have repressed and don’t feel at all! Our repressed emotions are often related to severe stress or trauma from as long as decades ago, Silently, they cause or contribute to hypertension and many other chronic medical conditions.

Hypertension driven by the SNS responds to treatment with a beta-receptor blocker, alone or in combination with an alpha-receptor blocker. The beta-blockers most commonly prescribed are metoprolol and carvedilol. My preference is bisoprolol. The alpha-blocker most widely prescribed is doxazosin.

In conclusion, it is important to identify what is actually causing your elevated blood pressure. I’ve covered the 3 main mechanisms and shared the resources for narrowing your investigation.

If you’ve been prescribed diuretics and your blood pressure is still not under control, take this article to your doctor and discuss these avenues of approach. Remember, you are not alone, and chances are there are millions of others who are having a similar experience with diuretics that are not working.

If you have not purchased my book, Hypertension and You; Old Drugs, New Drugs and the Right Drugs for Your High Blood Pressure, I highly recommend doing so. This will help you understand hypertension better and how to work with your doctor to come up with the best treatment plan.

And if the usual medications just are not working, pick up a copy of Hidden Within Us; a Radical New Understanding of the Mind-Body Connection. Your high blood pressure may be a result of or partial result of trauma you experienced years ago. I’ve been studying the mind/body connection for the past 30 years and have helped patients overcome chronic illnesses they thought would never go away.

Physician. Professor. Researcher. Author. Speaker.

Hypertension specialist, New York Presbyterian Hospital - Weill Cornell Medical Center



Hidden Within Us: A Radical New Understanding of the Mind-Body Connection

This award-winning book by Dr. Mann dives deep into the relationship between repressed emotion and illness. Our ability to repress emotions is a vital gift of evolution, but, silently, the emotions we've repressed do persist and can affect our health years later. This recognition can lead to new pathways to understanding, treatment, and healing.