— Connie, Ohio The jury is still out regarding the long-term effect of hydrochlorothiazide on blood glucose because the results from studies have been mixed. While some studies have shown that there is indeed a higher risk of elevated glucose, others have not confirmed this finding. Here’s what we know: Individuals who are taking thiazide diuretics, of which hydrochlorothiazide is one, can develop a mild case of elevated glucose, usually if their potassium levels are also low. When the potassium level normalizes, the glucose level goes back to normal. Thiazide diuretics have proven beneficial to people with high blood pressure and are among the best, safest, and least expensive of blood pressure drugs. The use of beta-blockers (which are also prescribed to treat high blood pressure) along with thiazide diuretics can, however, increase blood glucose levels. It is possible that hydrochlorothiazide increases the production of glucose from the liver, and because beta-blockers limit the absorption of glucose into cells, the use of these medicines in tandem can raise glucose levels significantly enough to cause diabetes. My recommendation is this: Make sure your potassium level is normal or high-normal when taking hydrochlorothiazide. If your doctor tells you that your levels are low, eating bananas — which are rich in potassium — can help. And, unless absolutely necessary, avoid mixing beta-blockers with hydrochlorothiazide. Your best bet is to visit your doctor. Ask him to explain the benefits and risks of taking hydrocholorthiazide versus some other antihypertensive drug. Q2. I have had type 2 diabetes for ten years now. I’ve never had high blood pressure, and I don’t now, so why did my doctor prescribe a blood pressure pill along with my diabetes pills? Very good question. At face value, your doctor’s decision doesn’t make sense. But this sort of practice is not unusual — for example, physicians often prescribe blood pressure medicines to prevent migraine headaches, or antidepressants to manage pain. Medicines intended to treat a specific problem can have secondary benefits that ease others. So why would medicines for high blood pressure be prescribed for diabetics who do not suffer from hypertension? As you know, diabetes is one of the leading causes of kidney failure. We know that as the kidneys fail, more protein is spilled in the urine. Certain types of blood pressure medicines reduce the pressure in the kidneys, thereby reducing the amount of protein they excrete. Through this process, kidney failure may be delayed or averted altogether. The classes of blood pressure medicines that have been proven to have such an effect are ACE inhibitors (lisinopril, ramipril, enalapril and captopril), angiotensin II inhibitors (irbesartan, telmisartan, losartan), and a specific subclass of calcium channel blockers (diltiazem, verapamil). I suspect your doctor started an antihypertensive to protect your kidneys. Next time you visit, ask your doctor if this is the case. Learn more in the Everyday Health Type 2 Diabetes Center.
