One of the most commonly prescribed drugs in the world today is a diuretic called hydrochlorothiazide. That’s a mouthful. Not surprisingly, health professionals abbreviate this medication. It sometimes appears as HCTZ. That is sometimes shortened to HCT or HZT. It is often found in brand name blood pressure medications so a patient might not even realize she was taking HCTZ. Most physicians perceive this drug as super safe. They may not mention that HCTZ can raise blood sugar levels.
According to our calculations over 23 million Americans swallow HCTZ daily to control blood pressure or control fluid buildup. Most people assume that this diuretic has few, if any, side effects.
HCTZ and Potassium Problems:
If patients are warned about a potential problem it might be that hydrochlorothiazide can deplete the body of potassium. Advice may range from eat a banana and drink some orange juice to sprinkle your food with a salt substitute containing potassium chloride. What many people are not told is that HCTZ can raise blood sugar.
HCTZ CAN Raise Blood Sugar Levels:
Q. I took hydrochlorothiazide (HCTZ) for 14 years to control blood pressure. When I started, my blood sugar was completely normal. Within a few years it began to climb.
After my doctor doubled my HCTZ dose, my fasting blood sugar soared. No one ever warned me that diuretics could cause diabetes. Would changing my BP drug help me with my diabetes?
A. Many medications, including diuretics like HCTZ can raise blood sugar. That is NOT a message that is well received by some physicians.
Chastised by Doctors Who Reject Side Effects:
A couple of years ago Dr. E.B.M. responded to an article we wrote for our syndicated newspaper column titled: Do Common Medicines Trigger Diabetes.
Here is his outraged reaction:
“As a Board Certified Internist and Emergency Room physician for 21 years, I must reply to this. My mother sent me the link wondering if taking of lisinopril would also ‘trigger diabetes.’
“Please read the article I am attaching in its ENTIRETY to better understand the pros and cons of thiazide diuretics. Perhaps it will persuade the reader to not leap to the conclusions so irresponsibly presented on The People’s Pharmacy:
“Joe and Terry, you are promoting dissent and insidiously advising patients to question the competence of their physicians with poor research examples and a lack of unbiased attention to the real data available. It’s embarrassing even reading what you have written on your website.
“And just to settle the issue:
“If a patient chooses not to take a medication because of a side-effect that ‘might’ happen, then you might as well take nothing. There’s no such thing as a harmless medication, be it herbal, ‘natural,’ or pharmaceutical. Medicines can harm and they can help. We, as physicians, deal with the ‘probable.’
“This is a fact of medicine. There ARE no absolutes. HCTZ will PROBABLY not cause you to get diabetes. Can’t say absolutely, but PROBABLY not. If you get diabetes on it, its far more likely you developed the diabetes for other reasons (as the article linked mentioned).
“Any physician worth his salt would certainly look to consider an alternative if necessary, but if the benefit of the HCTZ outweighs the risk, then the best choice MIGHT be to continue it. Perhaps the diabetes can be managed with the same diet that SHOULD have been present before the hypertension started….i.e. low sodium and low carb.”
People’s Pharmacy Response:
Ouch! That hurts. We responded to Dr. E.B.M. by asking why he didn’t reassure his mother that lisinopril was not a thiazide diuretic and does not raise blood sugar. That would have been the obvious answer. But Dr. E.B.M.’s reaction went way beyond the obvious.
We prefer not to get into arguments whenever possible. Our readers came to our defense:
Sal J. wrote in response to Dr. E. B. M.:
“In response to Dr. EBM, I in no way believe that the Graedons are ‘promoting dissent and insidiously advising patients to question the competence of their physicians.’ They simply are reporting a patient’s experience and that the diuretic HCTZ (hydrochlorothiazide) could have raised his blood sugar levels high enough to trigger a diagnosis of diabetes. [Here is a link to the original article]
“They are not telling people to abandon their medications (and never do) but simply to be aware of possible side effects causing diabetes, which are the exact same warnings enclosed with the inserts I receive in my losartan/HTZ and amlodipine prescriptions from the pharmacy.
“Pharmaceutical companies list the side effects they absolutely have to…no more. Most physicians have little information aside from what they’ve been told by their drug reps. I like to be in partnership with my internist specializing in geriatrics, but he does not keep up with recent studies so easily available to everyone, including doctors.
“When my blood glucose suddenly became elevated, I showed him recent studies (The Lancet, Archives of Internal Medicine and JAMA), revealing that women especially over age 50 taking statins could experience a significant risk of developing diabetes. He wouldn’t even read it saying, ‘It depends who you listen to.’ At the end of our meeting, he said, ‘I do have a doctorate.’
“I didn’t have high cholesterol but I do have uncontrollable risks for diabetes, so I took myself off my pravastatin, because I realize this drug I have taken for a long time could become a problem as I have gotten older (I am 74). He also prescribed levaquin (with a bold black box warning) to my husband who could hardly walk after only three of five tablets for bronchitis; our elderly neighbor ruptured his Achilles tendon while on long-term Cipro.
“With a now elevated blood glucose, I am looking into all areas for improving this situation including diet, exercise and medications since 96 percent of the nearly 26 million Americans with diabetes have type 2 diabetes and I don’t want it. In the meantime, I welcome further newsletters from the Graedons with their up-to-date messages and alerts.”
A different doctor (Michelle) agreed and disagreed with Dr. E.B.M.:
“I have had many patients on HCTZ and it can cause hyperglycemia [elevated blood sugar]. I have yet to see a patients develop diabetes from HCTZ after 30 yrs of practice.”
Another reader, H.J.L., offered this perspective:
“Sorry EBM, I think your attack on the Graedons was over the top. I don’t think you read every word of what the Graedons said.
“You may be the best emergency doc in the world, but you deal with patients on a short term basis. Managing long term care has its own set of requirements.There are many docs out there who are not good, who don’t keep up and don’t listen. For a doc to deny the possibility that a diuretic could cause onset diabetes is malpractice.
“Your mother acted reasonably asking you for help about her lisinipril. What’s the big deal? There is nothing non-factual in what the Graedons said. Besides the diabetes issue, they raise the fact that perhaps potassium supplementation should be explored.
“I read almost all of the article you cited and do not have the background to understand everything in it. But I found nothing in it that contradicts anything the Graedons said. In fact it supports it. This is a direct quote from the article you cited: (Note: NOD is new-onset diabetes):
“In conclusion, we should refrain from underestimating the adverse prognostic impact of NOD induced by diuretics and β-blockers, alone or combined, solely because of the failure by most randomized trials to disclose a significant association between NOD and outcome. NOD, whether or not induced by drugs, remains an important adverse prognostic marker that should be prevented. We suggested that in subjects at increased risk of NOD (impaired fasting glucose, obesity, metabolic syndrome), diuretics and β-blockers should 1) be used cautiously, with the lowest effective dose and plasma glucose periodically checked, and 2) be avoided in subjects with BP normalized by different classes of antihypertensive drugs.”
H.J.L. goes on to write:
“I am sorry your mother ‘bothered’ you with her reasonable question. But please read your own sources more carefully before you attack others who are completely factual. If I am wrong, cite one factual error in what the Graedons said.” [again, here is a link to the original article]
Another Reader Says HCTZ Can Raise Blood Sugar:
“I was prescribed hydrochlorothiazide by my previous doctor as an additional high blood pressure medicine. I took it for years.
“My previous doc never told me it would RAISE my blood sugar. Just before I changed doctors, I was diagnosed with type 2 diabetes.
“My new doctor took me off hydrochlorothiazide and changed me from the other high blood pressure med I was on. It was causing me a chronic cough which the former doctor never admitted was caused by my medicine!).
“MY ADVICE: Discuss with your doctor any possible drug side effects. If he has his head in the sand and refuses to discuss complications, FIND A NEW DOCTOR!”
The People’s Pharmacy Perspective:
In response to the original question we suggest that the person should ask the doctor about other options for controlling hypertension that will not elevate glucose levels.
Anyone who would like printed copies, please send $6 in check or money order with a long (no. 10) stamped (70 cents), self-addressed envelope:
- Graedons’ People’s Pharmacy, No. DMB-17
- P. O. Box 52027
- Durham, NC 27717-2027.
Hydrochlorothiazide is also found in medications like:
Share your own thoughts about HCT in the comment section below. Other side effects of hydrochlorothiazide include: low potassium levels, low sodium levels, low magnesium levels, low calcium levels, muscle cramps, high uric acid levels, elevated lipid levels, low blood pressure upon standing (orthostatic hypotension), dizziness, digestive distress (loss of appetite, diarrhea), erectile dysfunction, weakness, skin rash, kidney damage and blood disorders.
Such side effects may be rare, but we believe it is important for people to know what side effects to be alert for. If they do not occur, great! If they do occur, a conversation should occur with the prescriber. No one should ever stop any medication without discussing it with the prescribing physician!