The People's Perspective on Medicine

Hydrochlorothiazide Side Effects: Skin Cancer and More!

Very few health professionals think hydrochlorothiazide side effects are serious. A new Danish study links HCTZ with skin cancer (squamous cell carcinoma).
Illustration of doctor’s desktop with different pills, capsules, statoscope, syringe, yellow folder with label ‘Skin Cancer’

You have been advised by the American Heart Association and the American College of Cardiology that if you have systolic blood pressure of 130 or higher and/or diastolic blood pressure of 80 or higher that you have hypertension. That means at least half of all adults in the United States now have high blood pressure. The chances are good that many of them will be prescribed thiazide diuretics as first line therapy. But what are hydrochlorothiazide side effects? And are they serious?

Hydrochlorothiazide (HCT or HCTZ): One of The Most Popular BP Drugs in the World:

One of the most popular blood pressure pills in the world has been linked to skin cancer. More than 20 million Americans take hydrochlorothiazide or HCTZ every day. It is found in dozens of combination blood pressure pills and has been perceived as an extremely safe choice for controlling hypertension.

A new study from Denmark, however, suggests that this thiazide diuretic is associated with squamous cell carcinoma (Journal of the American Academy of Dermatology, April, 2018). This type of skin cancer is linked to excessive sun exposure. HCTZ sensitizes the skin to ultraviolet radiation from the sun.

The study included 80,000 Danish citizens with non-melanoma skin cancer. Those who took the highest dose of hydrochlorothiazide for the most years were seven times more likely to develop squamous cell carcinoma than people who took no HCTZ. The scientists looked at other blood pressure medications and did not find any similar associations.

Squamous Cell Carcinoma:

When most people think about common cancers they immediately imagine breast cancer, lung cancer, prostate cancer and colon and rectum cancer. According to the American Cancer Association, the projections are that in 2017 there will be:

253,000 cases of breast cancer
222,000 cases of lung cancer
161,000 cases of prostate cancer
135,000 cases of colorectal cancer

It comes as a total shock to learn that the American Academy of Dermatology estimates that:

“Squamous cell carcinoma (SCC) is a common skin cancer in humans. About 700,000 new cases of this skin cancer are diagnosed in the United States each year.”

Most people do not worry much about skin cancer unless there is a diagnosis of melanoma. They assume that squamous cell carcinoma is not that big a deal. Although squamous cell carcinoma (SCC) is often successfully treated with surgery, it can occasionally be lethal. An article in JAMA Dermatology (May, 2013) noted:

“Cutaneous squamous cell carcinoma [CSCC] carries a low but significant risk of metastasis and death. In this study, patients with CSCC had a 3.7% risk of metastasis and 2.1% risk of disease-specific death.”

Hydrochlorothiazide Side Effects and Squamous Cell Carcinoma:

The Danish researchers have been concerned about the link between hydrochlorothiazide and squamous cell carcinoma for some time. They reported in the Journal of Internal Medicine (Oct. 2017) that “Hydrochlorothiazide use is strongly associated with an increased risk of lip cancer.” They described it as a “clear dose-response effect.” In other words, the greater the exposure to the drug the more serious the risk.

In their new publication, they note:

“Recently, we reported a strong association between use of the diuretic hydrochlorothiazide (HCTZ) and squamous cell carcinoma (SCC) of the lip. We found a clear dose-response pattern, with an estimated 7-fold increased risk of SCC lip cancer with cumulative use of ≥100,000 mg HCTZ. Our findings were in line with the results of previous studies from the United States (US) and the recent classification of HCTZ as ‘possibly carcinogenic to humans’ (Group 2B) by the International Agency for Research on Cancer (IARC). As HCTZ is among the most widely used drugs in the US and western Europe, a carcinogenic effect of HCTZ would have a considerable impact on public health.”

The authors conclude:

“In conclusion, given the considerable use of HCTZ worldwide and the morbidity associated with NMSC [non-melanoma skin cancer], a causal association between HCTZ use and NMSC risk would have significant public health implications. The use of HCTZ should be carefully considered, as several other antihypertensive agents with similar indications and efficiency are available, but without known associations with skin cancer.”

The People’s Pharmacy Perspective:

Hydrochlorothiazide is considered very safe by most physicians. This diuretic is often the first line treatment for high blood pressure. What is especially concerning is that many patients don’t even realize they are taking HCTZ. That’s because it is frequently added to another drug such as an ACE inhibitor a beta blocker or an ARB. For a list of drugs containing hydrochlorothiazide, please visit this link.

Other Hydrochlorothiazide Side Effects:

There are a surprising number of hydrochlorothiazide side effects that often go unmentioned. They include electrolyte imbalances, elevated blood sugar, raised uric acid levels, muscle cramps, irregular heart rhythms, dizziness, elevated cholesterol levels, and dry eyes.

To learn more about hydrochlorothiazide side effects, visit this article:

Hydrochlorothiazide (HCTZ) Side Effects, Complications and Gout!

Share your own story about hydrochlorothiazide side effects in the comment section below. If you have done well with this drug we would like to hear from you as well.

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    About the Author
    Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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    I was prescribed HCTZ to treat hypertension caused by other medications I was taking on doctors’ orders. I developed a severe skin condition from HCTZ. My entire torso, buttocks, thighs, neck, and the lower portion of my face were involved. It was an intensely itchy rash accompanied by a persistent sensation of being pricked by hot needles over all of my skin. It was eighteen months of misery! When a dermatologist finally decided to biopsy one of the moist plaques on my back, the pathologist opined that it appeared to be a medication reaction. The prescribing physicians scoffed at that opinion.

    Despite this, I pinpointed HCTZ as the culprit by the simple expedient of discontinuing it for a time and observing that the progress of the rash, which was continuing to spread and beginning to disfigure my face, was halted immediately and that when I resumed the drug, the rash immediately began spreading. I stopped taking HCTZ. The rash stopped spreading, and the existing plaques began to heal. It took a couple years for the scars to fade. That was circa late 2012. That experience, along with other negative effects of medications, led to my swearing off of most pharmaceutical drugs, despite the eagerness of my physicians to prescribe them. I even eschewed chemo and radiation for the treatment of cancer and am cancer-free four years later, which is as good as what I could have expected with conventional treatment.

    For solution to high blood pressure:
    1. if your family is crazy move away from them NOW!
    2. if your neighbors are crazy move away from them NOW!
    3. if your town is crazy (like Winston Salem/Greensboro/) move away from there NOW!
    4. listen to the 1970’s song SUNSHINE by Jonathan Edwards

    Joe, does Chlorthalidone cause skin cancer the same as HCTZ? They are both diuretics and related but not exactly the same I have been told. Without Chlorthalidone, my right leg swells, but it causes side effects too such as thinning hair and urine frequency and urgency and no telling what else it is causing. Valsartan does the same thing and I took Solco valsartan, now recalled because of cancer ingredients. Solco was the cheapest for pharmacies so that generic brand was all they carried. I hate taking drugs made in China or India.

    Been taking lisinopril hctz 20-12.5 since 1996, from that time on the per-cancer carcinomas keep appearing on my head and in 2013 a squamous cell carcinoma appeared on my upper lip that was the size of a nickel. I have often thought that the blood pressure pill I was taking caused the skin cancers. I am quitting the HCTZ.

    I am tired of the expense of the Blue Light Special, Nitrogen Freeze and the fact that the Dermatologist can’t keep the knife in his pocket (he always finds something to cut off).

    I am tired buying him a new Corvette every couple years.

    I have recently stopped HCTZ(triamtereneHCTZ 75/50) with my doctors approval. I have taken it as long as 2006 and have had BC/SC carcinomas since then….and NOT just one or two spots! In fact, my dermatologist at the time, stated on my med records that he wondered why I had so much! I have been through every treatment known to mankind, “freezing, Mohs surgery, blue light therapy, and cream (Fluorouracil) and I STILL have the pre-cancers and was, just recently, diagnosed with Malenoma in situ.

    How long will I have to put up with this stuff (I just quit taking Triamterene 1/19/2018)? And where is the class action lawsuit against this, so others won’t have to put up with all the pain, discomfort, embarrassment and cost of trying to rid themselves of the BC/SC carcinomas?

    I had an unsuccessful prostatectomy 8 years ago and after a subsequent course of intermittent hormone therapy [Zoladex implants] my PSA became and remained undetectable on three monthly readings through June 2017. Blood test on 5 March 2018 showed detectable albeit low PSA of 0.026. I also have recent actinic keratosis. I commenced taking HCTZ [in Candesartan Plus] 5 months ago. As I see it [yet to discuss this with my oncologist] the literature is consistent with the conclusion that HCTZ somehow “teases” prostate tissue, and also with the conclusion that HCTZ increases the risk of keratosis – and more.
    For me, I think these risks are not acceptable.

    I am completely devastated to find out about this medication I have been on since around 2007. In 2016 I was diagnosed with squamous cell carcinoma. I had to have 5 surgeries to have the left side of my nose removed and to rebuild what was taken. Almost the entire left side of my nose had to be removed and my septum collapse during surgery so they had to remove cartilage from my ear to rebuild my septum. It was truly a night mare and the most painful thing I have ever had to go through. Thank God I had wonderful doctors because it was very hard to deal with I was scared to death. I was under the care of doctors from late 2016 to July 2017 receiving treatment. This is truly devastating to find out this this medication causes this type of skin cancer I had no idea.

    I’ve been taking moduretic for at least a decade. I’ve had 2 major bccs removed plus some smaller ones, and now have a number of sccs and bccs on my face. What a pain, the bp meds I took first made me virtually brain dead and a menace on the road. Must investigate some lifestyle remedies.

    I have been taking HCTZ with Losartan. I began to wake up at night with short breath, nausea and light headed.

    I stopped taking both. All of these symptoms disappeared.

    This report comes from Denmark, where perhaps most or all study subjects are of Scandinavian origin and are among the most fair-skinned people on the planet. (In the reports I read, I did not see a description of the skin type of the study subjects.) Many, or most US persons, have a darker skin type. We don’t know whether the study finding of increased SCC incidence with HCTZ use applies to this different population. We also don’t know from the articles I saw whether the risk of SCC rose 7-fold from 0.1% to 0.7% or from 2% to 14%.

    I have taken blood pressure medication with 25 mg HCTZ for many years. Three years ago I developed and had removed squamous cell carcinoma on skin between my lip and nose. Who knew? Now I’ll be asking my internist about the connection.

    i have taken 12.5 of hdcz for at least 20 yrs w/ other hp meds. very interested the comments and facts mentioned . no squamous but lots of basal cell on face which do not apply. we recently talked abt upping hdcz to 50. glad i didn’t.

    I have been taking this drug for several years and this article definitely concerns me. I have noticed sun sensitivity and recently, a lot more “skin tags” and skin spots that everyone has chalked up to age (I’m 56) but now I’m wondering….and will definitely be talking to my doctors about this. I was prescribed Losartan-HCTZ because the first newer blood pressure pills didn’t work and the second one they tried made me nauseous and dizzy within 30 minutes of taking it! This drug definitely worked to get my blood pressure down without side effects. What alternatives should I be researching?

    I use hctz for blood pressure and have had a lot of those symptoms: gout, cramps, dry eyes but the way I eat and whether I exercise can minimize and even alleviate those symptoms and getting my BP down right now is my priority.

    I was taking HCTZ for almost 30 years, and I just got my cardiologist to discontinue it. At first, my ankles swelled up, but I went back to HCTZ for a week and tapered down. My ankles are OK now, and night-time muscle cramping is much less troublesome and almost gone. I’ll have to see how I respond to potassium and magnesium supplements now. They used to give me terrible leg cramps and chest pain. Never had any skin cancer, but I tend to stay out of the sun.

    Took this for years. Dr took me off this last year. During this time I had cancer removed from my temple area. This year my neck. They want me back next month to start on my arms. I was shocked when I read this. Man, that’s bad when drs don’t say nothing about this. I have been through a lot but never realized it till now. Wow!

    I have taken this for years. 25 mg 1/2 tablet a day. Apx 12 mts ago dr took me off of it. I have had skin cancer removed from my temple area. My neck area and my arms are in bad shape. Next month I have to go back have more removed. I was shock when I read this material. Never knew how or why it started until now. WOW.

    I’ve never been interested in getting a sun tan so never spent time laying out in the sun nor in tanning salons. I’ve worked in offices during my working years and am not an outdoor person. I learned to swim as an adult in indoor swimming pools. I’ve read a lot, played bridge and square danced. All indoors. Liked sunny days but from shaded areas. No one in my family had skin cancer. When I developed squamous cell skin cancer at age 80, I was told it was from over exposure to the sun. That was puzzling to me and I wondered how that could be. Today I read that the reason may well be that I’ve taken spironolactone/HCTC 25/25 for maybe 30 years.

    I had to stop taking hydrochlorothiazide because it caused hair loss for me. My doctor switched me to another blood pressure medication that did not cause the problem.

    HCTZ gave me terrible kidney stone trouble. It was so bad I could not sleep.

    Other people I know on that drug had no such problem.

    Blood pressure drugs in general, give me kidney stone trouble.

    I was taking HCTZ a few years back for pitting edema (commonly know as having ‘cankles’ when it affects the feet/ankles). It did not work very well to reduce the swelling. Then my doc put me on Metolazone which did indeed help but also caused an unpleasant side effect, constipation.

    Luckily, I discovered nettle tea and it has worked like a charm for over 18 months now with zero side effects. My doc is still amazed (but won’t really admit it). Look it up, read and you’ll be amazed.

    A word to the wise is sufficient they say:


    With all due respect, I would suggest you be more circumspect with your headlines. My late mother was an avid reader of yours and always felt she was “smarter than her doctors.” She also had blood pressure that, when untreated, was pushing 200. Her knee-jerk reaction to your headline would be to toss her diuretics into the trash: “I can’t be taking something that causes cancer!”

    In the years before she passed away at age 91, she was hospitalized multiple times after blood pressure crises. Most seemed to be the result of failure to follow her medication regimen—sometimes by mistake, sometimes because she decided (without talking to her physician) that “she knew better” than to keep taking a particular med.

    Squamous cell carcinoma is undesirable and can even be fatal if untreated. Stroke is worse.

    Twenty one years ago my 75 year-old mother-in-law was in very very good health other than the blood pressure medicine her dr gave her. She developed a cough and raspy voice from it, but that wasn’t one of the side effects known back then. She also was taking a diuretic. She was on these meds for at least 5 years or more.

    In September of 1995 she had a spot on her upper gum and went to the dentist. He was alarmed and sent her to a specialist who diagnosed it after the biopsy as SQUAMUS cell cancer. She lived for 6 months and died in April of 1996. She developed squamus cell cancer in her eye, her lungs and then her brain.

    I truly wonder if this us why she got sick so quickly and died so fast.

    So all you naysayers, be aware. Take heed with what you put in your body even though you think it’s just a little. A little arsenic kills too.

    My 88 year old mother had been prescribed a high blood pressure prescription of 100 mg htcz daily by her previous doctor. I don’t know how long she took this. A different physician was shocked that she was on that high of a dose and changed it. She now has stage 3 kidney disease, type 2 diabetes and recently under went surgery for a squamous cell carcinoma and a resulting skin graft located on the very top of her head.

    So any suggestions on what could be prescribed as an alternative?

    I took benazepril 10 mg hydrochloride to 5-2015 , about 8 years.
    I do have skin cancer now.
    Mr. R

    Most people do not want to believe that any drug could cause them harm, until it does. There are a number of ways to bring down blood pressure but that would mean the patient has to actually do something proactive with their health. Most folks just want to pop a pill and believe that is the best thing to do. Well, it is the easiest for sure. Personally I cannot say it is the best course of action, so I choose to follow a more natural approach.

    This is depressing. I don’t have hypertension but I do take hydrochlorothyiazide daily because it seems to be a miracle drug for preventing the dizziness that occurs due to Meniere’s syndrome. I have had squamous cell carcinoma on my nose. Now I guess I have to decide whether to take my chances or return to days of debilitating nausea. Do you know if any of these other “antihypertensive agents with similar indications and efficiency” have been studied as treatments for vestibular disorders?

    In 2009 my neurologist prescribed hydrochlorothiazide to alleviate Meniere’s symptoms. I have been taking this drug ever since afraid if I stopped it might start these episodes again. I take a very small amount and it is not for high blood pressure, but earlier this year I had a growth removed from my arm that turned out to be squamous cell carcinoma. Is there a connection? I don’t know, but it sure startled me. I will show the article to my doctor, but am planning on tapering off this drug. This study was compelling enough for me.

    I’ve been taking 12.5 mgs of this drug, off and on, for many years and have not noticed any side effects. But this study does alarm me. Right now I’m losing weight and hope by next year I won’t have to take it all.

    Joe, I ‘ve been taking laods of HCTZ , like 65mg a day and so your article is important to me. I noticed sun burn within 15 minutes of sun exposure.

    Would you think taking 2,000 units of vitamin D3 with K2 a day would offer any protection against this type of skin cancer?

    About ten years ago, after an episode of severe vertigo, I was diagnosed with Meniere’s Disease. My ENT prescribed HCTZ for the Meniere’s along with a low salt diet presumably to “help regulate fluid balance”. I took it for about five years, never having another bout of severe vertigo, but still experiencing frequent dizziness. I also developed dry eyes. Two and a half years ago I was diagnosed with squamous cell anal cancer. One doctor told me that it was most likely related to exposure to HPV. After reading this article I am wondering if it was not caused or “helped along” by several years of taking HCTZ. (I am now cancer free, but experiencing lots of after effects from the chemo and radiation.)

    This alarmist piece will not cause me to hesitate popping my HCTZ this morning. Its protective effects against heart disease and stroke far outweigh these findings, IF they have any truth to them. (100,000 mg of HCTZ? Get serious!)
    I’ll also take my statin for the same reasons. Both drugs save lives.


    You clearly did not understand the Danish authors reference to a cumulative dose of 100,000 mg of HCTZ. They were not referring to a daily dose, but exposure over a long period of time. Not uncommonly people take 25 to 50 mg of HCTZ daily. If one were to take the lower dose for 12 years, the total cumulative dose over that time period would be over 100,000 mg of HCTZ. Someone taking a 50 mg dose would reach that level after six years. Many people with hypertension take such drugs for decades.

    I don’t use a diuretic but I would like to know what they recommend instead?

    There are a few other meds you can take to get rid of water but they don’t agree with everyone. I was on HCTZ for many years and then developed AFIB. I had been careful, and although I was very careful about going in the sun as I got older, even though we live in Fl, it’s very hard to avoid. I was sitting in my daughter’s yard, under her patio roof. It got very warm, and I said “I have to go in.” As I got up and started walking my husband saw me, and I guess I didn’t look right, so he got up and grabbed me just as I was about to fall.

    We didn’t think at the time it was HCTZ but when it happened a couple of weeks later I went to the Dr, and he took me off it. Anyone that thinks this article is bogus is very foolish. My doctor took me off it, and I have been taking Lasix now for a few years. I feel much better since taking it. And for me it gets rid of the water much better. In any case, you should drink plenty of water because even if you have a problem with swelling in your legs not drinking water is a mistake and can only cause you even more problems.

    I was on HCTZ for two years, absolutely no improvement in BP.
    In addition I was constantly urinating and blood sugar was elevated along with imbalance in electrolytes.
    Losartan has aided in leveling BP, though readings elevate when I am not well rested.

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