Hydrochlorothiazide (HCTZ) Side Effects, Diabetes and Gout!

We suspect that hydrochlorothiazide (HCTZ or HCT for short) is one of the most prescribed drugs in America on a daily basis. HCTZ is taken regularly by over 15 million people. Many doctors believe that hydrochlorothiazide (HCTZ) side effects are mild and rare. Patients are not always warned about adverse drug reactions. We think people need to know more about this widely prescribed diuretic and blood pressure medicine. It may not be as simple as most healthcare professionals believe.

Hydrochlorothiazide (HCTZ) Side Effects:

We worry about electrolyte imbalances with diuretics such as HCTZ, chlorthalidone, chlorothiazide, indapamide, metolazone, etc. Many healthcare professionals worry about potassium depletion. But such drugs can also cause low levels of other crucial minerals such as magnesium and sodium. And yes, sodium depletion can be a problem, especially in the summer.

Most people have been told to consume less salt. But if sodium levels get too low, it can be a life-threatening situation! You can learn what happens when sodium goes too low at this link. When people sweat a lot and drink a lot of water during the summer, the risk of “hyponatremia” (low sodium levels) is increased!

Electrolyte Imbalances from thiazide diuretics:

• Low potassium levels (hypokalemia)
• Low sodium levels (hyponatremia)
• Low magnesium levels (hypomagnesemia)
• High calcium levels (hypercalcemia)
• Low chloride levels (hypochloremia)
• Low zinc levels

Question for You!

How often has your healthcare provider requested an electrolyte panel if you are taking a blood pressure medication? I am not talking about a standard blood test for things like LDL cholesterol, glucose, hemoglobin, potassium or creatinine. I am referring to electrolytes such as magnesium or zinc as well as sodium. Knowing what all these electrolytes are doing is important if there is a diuretic on board.

Zombified by Too Many Side Effects!

Most people zone out after seeing just a few of the many listed hydrochlorothiazide (HCTZ) side effects. They assume that such complications will never affect them.

Our bulletin boards and comments would suggest otherwise. The only way to truly grasp the meaning of such hydrochlorothiazide (HCTZ) side effects is to read stories from real people.

Let’s start with just one of these adverse reactions: blood glucose elevation.

Blood Sugar Elevations and Diabetes:

We got spanked a few years ago by an outraged physician. He was furious because we wrote that diuretics like HCTZ could raise blood sugar and sometimes trigger type 2 diabetes. He considered our answer to a reader’s question “thoroughly irresponsible.”

Here is that interchange:

Do Common Medicines Trigger Diabetes?

We’re not sure why this doctor was so upset. The FDA requires manufacturers of thiazide diuretics like HCTZ to state in the official prescribing information that:

“In diabetic patients dosage adjustments of insulin or oral hypoglycemic [diabetes] agents may be required. Hyperglycemia [diabetes] may occur with thiazide
 diuretics. Thus latent diabetes mellitus may become manifest during thiazide therapy.”

It’s not the only time we have been spanked. We do not understand why physicians get so ticked off when we mention drug side effects. It seems as if they would prefer we never mention possible problems…sort of the “see no evil, hear no evil, speak no evil” approach to drug information.

Mad MD Maintains HCTZ is SAFE! Ignores Low Sodium or Potassium!

Reports from Readers Re: Hydrochlorothiazide (HCTZ) Side Effects

Q. You heard from a reader who was on the blood pressure pill HCTZ and having trouble. She should discuss this drug with her doctor. I was on it for years, thinking it was a harmless “water pill.”

When I switched doctors, the new one did a study of my problems, symptoms and prescriptions. We discovered that HCTZ was raising my blood sugar. Years of use probably contributed to my diabetes diagnosis.

In addition, this diuretic counteracts the effects of losartan on potassium. Losartan increases potassium levels while HCTZ lowers it! This is confusing.

A. Hydrochlorothiazide (HCTZ) is a common diuretic (water pill) used to treat hypertension. It is frequently added to other blood pressure medications. Researchers recognize that HCTZ can raise blood glucose levels, even though they don’t fully understand the mechanism (Frontiers in Pharmacology, March 28, 2025).

You are correct that the effects on potassium can be confusing. Diuretics like HCTZ deplete the body of this crucial mineral. Both ACE inhibitors like lisinopril and ARBs such as losartan tend to preserve or even boost potassium levels. That is why it is crucial to monitor potassium while on such medications.

Chuck says:

“I have been on HCTZ for 14 years. When I started my blood sugar was completely normal, but shortly after I went into the pre-diabetic range.

“Fasting blood glucose [FBG] was in the 105 to 115 range for more than 12 years, then 18 months ago my physician doubled my HCTZ dosage from 12.5mg to 25mg, and 12 months ago I was diagnosed with diabetes (FBG of 151).

“The kicker is that not one of these physicians ever informed me that there was a risk that HCTZ could cause an increase in blood sugar, and after it became full blown diabetes not one has suggested a change in my blood pressure medication.

“I feel it is the responsibility of the prescribing physician to discuss with me all of the potential side effects, and we will make the decision together. In my case several physicians felt “they knew best” and decided for me. This is unethical, but unfortunately seems to be the norm for some in the medical community.”

Brian added this:

“What a surprise I have been have been struggling with blood sugar levels myself. I also take hydrochlorothazide. In addition, I was suffering foot pain, even though the test for gout was negative my Dr suggested Indomethacin. This website provided information about problems HCTZ can cause. What a relief to know more about side effects of this medicine.”

Angela also reported early problems with HCTZ:

“I’m taking HCTZ for high blood pressure. I’m 78 and pretty healthy and have been on the pill since 5/07. Because I come from a diabetic family, I always have my glucose checked with my cholesterol. This month, for the first time, my glucose was 113; high for me and worrisome.”

Gout: Another Hydrochlorothiazide (HCTZ) Side Effect

Q. I was on HCTZ to control my blood pressure for more than ten years. I suffered through many episodes of gout before I discovered that HCTZ raises uric acid levels.

I discussed this with my Internist, who said he could put me on allopurinol or take me off the HCTZ. I chose the latter, and my gout episodes have greatly diminished.

A. Gout is an excruciating inflammation of one or more joints linked to high uric acid levels. Diuretics like HCTZ (hydrochlorothiazide) can indeed raise uric acid levels. Such medicines are often prescribed to lower blood pressure.

Other readers have also experienced gout after taking HCTZ:

Tony in Florida says:

“I took HCTZ for about 15 years to lower my High BP. Soon after I started taking it, I started getting episodes of gout. Belatedly, I finally put the pieces together that HCTZ was a major contributor to my gout.

HCTZ and Cholesterol:

Muriel in Durham, North Carolina shared this story:

“I was disparaged by my primary doctor over side effects of HCTZ. My cholesterol began to rise with no great changes in my eating habits and despite my planned weight loss.

“When I mentioned that this was one of the side effects of HCTZ listed on the packaging and that I had read up on it on the internet, the doctor flew into something of a mini rage. I was also experiencing dizziness. I reduced my cholesterol by taking fish oil and lecithin.”

More Hydrochlorothiazide (HCTZ) Side Effects & Electrolyte Imbalances:

Even if people are warned about mineral imbalances with thiazide diuretics like HCTZ they may not appreciate how dangerous this can be.

Low Sodium and Potassium:

This past summer we received the following question from a concerned daughter:

“My elderly mother has been very conscientious about a low-salt diet. She never salts her food and is careful not to eat processed foods high in sodium. Despite this, her doctor diagnosed her with mild high blood pressure and put her on a diuretic called hydrochlorothiazide.

“Last week she got up in the middle of the night to go to the bathroom. She suddenly felt weak and collapsed. When the paramedics came in response to her call button, she was confused. They took her to the hospital and discovered that her sodium and potassium levels were perilously low. Could her medicine be responsible for this scary episode?”

Diuretics like HCTZ can deplete the body of critical minerals. That includes potassium, sodium, magnesium and zinc. When these electrolytes get out of whack it can be very dangerous.

Liz in Raleign, NC dodged a bullet with her diuretic-induced hyponatremia:

“I was in my neighbor’s yard around dusk to check on his cat. I fell on something and hit my head, ending up in the trauma intensive care unit for four days. I needed four staples in my head to close the cut.

“I had limited memory before I fell and no memory at all for about three days while in the hospital. The diagnosis: low sodium. Mine was 116. The normal range is 136-145. I had no noticeable signs before I fell that anything was wrong.”
Hyponatremia is diagnosed when sodium levels fall below 135 mEq/L.

Priscilla in SC didn’t get a definitive diagnosis, but…

“I have used HCTZ for several years; did have infrequent muscle spasms in the lower legs, frequent urination, bladder incontinence. Quite recently I suffered a fainting spell, with accompanying dizziness and shakiness. I am presently under a cardiologist’s care after three days of hospitalization. Doctor suspects HCTZ but haven’t decided on clear diagnosis.”

The New BP Guidelines:

The American Heart Association and the American College of Cardiology have determined that all Americans should get their blood pressure to 120/80 or lower. That means that nearly half of all adults in the United states (103 million people) will be exhorted to lower their BP. And that means lots more prescriptions for diuretics.

Most people can tolerate diuretics like hydrochlorothiazides without problems. If such drugs work to control blood pressure without side effects, that is fabulous!

But we fear that many people will not be told about hydrochlorothiazide (HCTZ) side effects. They may not be monitored for sodium, magnesium, potassium or zinc on a regular basis.

Perhaps even more disturbing, many people won’t even realize they are taking a thiazide diuretic. That’s because it is often tacked on the end of the name of the BP medicine as HCT or HCTZ without much explanation or warning about adverse drug reactions.

The PPP (People’s Pharmacy Perspective):

Diuretics like HCTZ are generally inexpensive. They lower blood pressure and can help control fluid build up (edema). Side effects are not as serious as with some other BP meds. But patients must be told about problems like dizziness, electrolyte imbalances and some of the potential complications like gout.

Frequent blood tests are essential to make sure minerals like magnesium, zinc, sodium and potassium are not creeping into the danger zone. No one should stop this medication (or any other) without careful consultation with the prescribing physician. If hydrochlorothiazide (HCTZ) side effects become troublesome, however, doctors have a number of other options for treating elevated blood pressure.

Share your own story about diuretics in the comment section below. We want to hear success stories as well as tales of woe and intrigue. And we would be so grateful if you would share this story with friends or family members. If 1 out of 2 older adults has high blood pressure, there is a good chance that half your acquaintances would now be considered hypertensive. Many could be taking a diuretic like HCTZ. Your help in getting out the word about appropriate testing would be most welcome. You might also find our eGuide to Blood Pressure Solutions helpful. You can find it under the Health eGuides tab. Thank you for supporting our work.