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

Hydrochlorothiazide (HCTZ) is one of the most prescribed drugs in the US. It is a diuretic that helps lower blood pressure. At last count, over 10 million people swallow this pill daily. But HCTZ is also combined with blood pressure (BP) drugs like lisinopril, losartan, valsartan, olmesartan, bisoprolol and triamterene. That adds another 7 million people. Then there are all the other diuretics, but that’s a longer story. A lot of people believe HCTZ is safe, and yet there are side effects. One physician took us to task about the connection between hydrochlorothiazide and elevated blood sugar. He also seems to have ignored the possibility of low sodium and potassium levels, especially when the weather is hot, people are sweating and following instructions to drink lots of water.

MD Is Mad as Hell! He Says HCTZ Is Safe:

Q. I am a retired physician who was also a pharmacist. I believe your answer about hydrochlorothiazide (HCTZ) and diabetes is misleading and may potentially scare patients away from a beneficial medication.

HCTZ may increase blood sugar a few points, but it does not cause a person to become diabetic. According to several studies, the benefits of lowering blood pressure outweigh the slight increase in blood sugar elevation. Please don’t make a physician’s job more difficult.

A. Thank you for pointing out the important role that diuretics like HCTZ play in the treatment of high blood pressure. Let’s revisit our previous Q&A:

Q. I took hydrochlorothiazide for ten years to treat blood pressure. As a result, I developed diabetes, for which the doctor prescribed some pills I don’t like.

When I saw my new doctor last spring, I provided a list of vitamins and food that I eat in place of pills to control diabetes, blood pressure, and high cholesterol. He read the list and then he looked at me and said: “If this is what you are doing keep it up! All of your numbers are low!”

Mostly it was just common everyday food such as garlic, turmeric, cinnamon and vinegar water. I am just about through with diabetes. I think people should know about these options.

Prior Answer:

A. Hydrochlorothiazide and similar blood pressure diuretics can raise blood sugar, as you learned through experience. Generally, doctors prescribe medications to control diabetes, though diet and exercise can be very helpful.

We’re impressed you have done so well, and it makes sense for you to have your doctor monitor your progress. There are many non-drug ways to control blood sugar and you are using several of them. Both turmeric and cinnamon have research that supports their effectiveness.

HCTZ Is Safe…But There Are Side Effects

Meta-analyses show that, on average, the increase in blood glucose associated with HCTZ is small (Journal of Clinical Hypertension, April 2016; Journal of General Internal Medicine, June 2020).

Most people probably have no difficulties with this effect. For a few individuals, however, it might become worrisome. Some people are more susceptible to drug side effects than others.

It is always important to warn people about potential adverse reactions so that they can be alert for complications. It would be sad if someone developed diabetes because of an adverse drug reaction and did not realize it could be corrected just by changing medicine.

We urge all readers to work with their physicians to balance benefits and risks appropriately. The person who contacted us about HCTZ raising blood sugar was able to control both their blood pressure and diabetes with nondrug approaches.

Other Complications from HCTZ:

Because doctors prescribe hydrochlorothiazide so frequently, they may take it for granted. We agree with this doctor that HCTZ is “safe,” but there are potential adverse reactions patients need to know about.

Loss of Minerals: Sodium, Potassium and Magnesium!

Americans have been told that sodium is their enemy and that they must cut back on salt. That may be fine for many people, but there are exceptions. If sodium levels fall too low, it can turn into a life threatening crisis as you will read at this link:

“Is a Low Salt Diet Dangerous for Your Health?”

Diuretics like HCTZ can deplete the body of sodium. They can also reduce levels of potassium, magnesium and zinc. What happens when sodium levels fall too far?

Examples of Hyponatremia (Low Sodium Levels):

Q. My mother was prescribed HCTZ for high blood pressure. Her potassium and sodium levels had not been tested in three years, although she saw her doctor for yearly checkups. She ended up in the hospital for three days due to incredibly low sodium levels.

At the time, the area was in a heat wave with very high temperatures and humidity. She was sweating and drinking water to stay hydrated. All of this worked together to cause the dangerously low sodium and potassium levels.

Her hands were beginning to shake. We were lucky she didn’t have a seizure or die. The hospital doctors took her off HCTZ.

A. Potassium and sodium are critical minerals. The body tries hard to keep both in balance, but some medications can interfere with that outcome.

Consequences of Low Sodium and Potassium:

If sodium levels drop below 135 mEq/L, people may develop serious symptoms, including confusion, muscle cramps, weakness, loss of appetite and nausea. When potassium levels fall below 3.5 mEq/L people may develop similar symptoms. These can include muscle cramps, confusion, fatigue, weakness and irregular heart rhythms.

Hydrochlorothiazide (HCTZ) can deplete the body of both sodium and potassium. You can learn more about the effects of various antihypertensive medicines in our eGuide to Blood Pressure Solutions. This online resource is located under the Health eGuides tab.

Drinking a lot of water in hot weather may contribute to both low sodium and low potassium, especially if there is a diuretic on board. Electrolyte-containing beverages might be safer at this time of year.

Kris also reports hyponatremia (low sodium) after her doctor added HCTZ:

“I was given HCTZ in addition to 2 other blood pressure meds because my blood pressure was still quite high. My sodium level when I started HCTZ was 134 (a little below normal) and after six days fell to 121. I was feeling very fatigued, achy and not as clear headed as normal, went to the ER and was diagnosed with hyponatremia (low sodium). I was hospitalized for 6 days for treatment to slowly raise my sodium blood level. I understand that most people don’t have any trouble at all with HCTZ but it is important to have sodium levels drawn when on the medicine.”

Lora shares a tragic story about low sodium levels:

“My mother was on high blood pressure pills and HCTZ for at least ten years. She would retain water but doctors were not careful enough with monitoring her. She had to go to the hospital several times because of low sodium – was extremely weak and had gout-like symptoms.

“She was in assisted living facility the last year of her life. They would not let her take her meds on her own even though she had always done so. There was nothing wrong with her mind – sharp as a tack. She was sure the nurses were not giving her meds correctly. She was sent to the hospital because she was in excruciating pain and died 36 hours later. Cause of death was hyponatremia.”

Low Potassium Levels = Hypokalemia:

Diuretics like HCTZ can deplete levels of other minerals besides sodium. Low potassium levels can also be life-threatening. This condition is called hypokalemia.

Caralyn reveals a story of HCTZ and low potassium levels:

“I have been taking low-dose HCTZ for a number of years. About ten years ago I felt unsteady when bending over (for instance, to pick something up from the ground). I didn’t know what was going on with that, and didn’t rush into the doctor.

“During this time period I was scheduled for an angiogram. A blood draw was done right before the procedure, and it was discovered that my potassium levels were so low that if my heart had stopped they wouldn’t have been able to restart it. Whoa!

“I have been on prescription potassium ever since and have done well. My BP is down in a very good range with the HCTZ and my potassium levels are good too. I’ve stayed at the same low dose HCTZ all these years, and those are the only two prescription meds that I take. I appreciate the resource of People’s Pharmacy to inform the public of potential risks of various drugs and the benefits of trying other avenues for good health. Thank you.”

Hydrochlorothiazide and Gout:

When uric acid levels go too high, a person can experience gout. The pain in joints can be excruciating. People should always be warned that diuretics like HCTZ can raise uric acid levels. Here is a link about just such a reaction:

Carol ended up with both gout and elevated blood glucose:

“I am so glad you are on top of things informing people of the many side effects that can happen from medicine. My doctor told me I have AFIB and HBP and started me on blood pressure meds and a blood thinner. I could not take almost every BP med. Your list showed many of the meds I tried and could not take

“I also was on HCTZ and ended up in the ER with gout, and now my blood sugar is elevated. So I am watching that. Also,I had a severe muscle cramp in my left calf that lasted for a year and a half, as NO doctor could diagnose its cause.”

Jack reports an association between HCTZ and gout attacks:

“I have serious gout! The HCTZ is a major contributor to gout attacks. Doesn’t cause gout but increases the frequency and severity of attacks. I started HCTZ 15 years ago, and I also started having violent attacks of gout then as well. I never knew the correlation until last month. I stopped HCTZ and replaced it with another BP medicine and my gout attacks have subsided.”

Readers may find this article of interest because it digs deeper into the pros and cons of diuretics like hydrochlorothiazide.

Hydrochlorothiazide (HCTZ) Side Effects, Complications and Gout!

That article also provides more detail about electrolyte imbalances:

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

HCTZ Is Safe…But What About Skin Cancer?

Most doctors know that diuretics like HCTZ can deplete the body of sodium, potassium and magnesium. And they should realize that in hot weather when people are drinking a lot of water, iced tea and other beverages, regular tests for electrolyte balance are essential.

There is another side effect that we worry about, though. We suspect that most physicians have never heard about a connection between hydrochlorothiazide and skin cancer. It is controversial. Here is a link to an article about HCTZ and squamous cell carcinoma. The diuretic may make the skin more sensitive to ultraviolet radiation from the sun.

Here is an article in the journal Evidence-Based Dentistry (March, 2022).

The authors conclude:

“The risk of NMSC [non-melanoma skin cancer] and lip cancer in a UK population is increased with cumulative high-dose HCTZ exposure. It is therefore important for dentists to note as it may increase suspicion of lesions in patients taking these medications.”

The association was confirmed in the European Journal of Clinical Pharmacology (June, 2022).

“Purpose: The aim of this study is to investigate the association between hydrochlorothiazide (HCTZ) use and the risk of cutaneous [skin] and lip squamous cell carcinoma development.

“Results: A total of 2181 published studies referring to the theme were identified, from which six were included in this systematic review… This meta-analysis demonstrated a chance of developing cutaneous and lip squamous cell carcinoma in any region of the body in hydrochlorothiazide users of 1.76-fold higher than in non-users. In addition, a risk factor of 1.80 higher of cutaneous squamous cell carcinoma in the head and neck region was observed in HCTZ users.

“Conclusions: Our results confirm the association between the use of hydrochlorothiazide and the cutaneous and lip squamous cell carcinoma development.”

In August, 2020 the FDA issued a Drug Safety Communication about the use of hydrochlorothiazide and a subsequent risk of skin cancer. A follow-up study found that despite the new warning, prescribing patterns did not seem to change, even for patients with a history of skin cancer (Pharmacoepidemiology and Drug Safety, Oct. 2024).

Final Words:

Diuretics are helpful blood pressure medications. And there are other cardiovascular conditions that require diuretic treatment. But low sodium and potassium levels are worrisome. A study published in the American Journal of the Medical Sciences (Aug. 2025) points out that BP meds that cause hyponatremia can lead to falls. And falls lead to fractures.

We offer information on the pros and cons of BP medications in our eGuide to Blood Pressure Solutions. This online resource may be found under the Health eGuides tab. It also discusses a number of non-drug ways to help control high blood pressure.

Please share your own experience with blood pressure medications in the comment section below. If a friend or acquaintance is taking blood pressure medicine, why not share this article with them? Just scroll to the top of the page and click on the icons of email or social media. We would also be super grateful if you encouraged people to sign up for our free newsletter at this link. It helps keep The People’s Pharmacy moving forward.