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Hydrochlorothiazide and Diabetes

Hydrochlorothiazide and Diabetes


Insulin is a hormone that is secreted by the pancreas. Diabetes can develop when the pancreas stops secreting insulin or when the body becomes resistant to insulin. The most common type of diabetes is type 2 diabetes.

According to the American Diabetes Association, more than 25 million people have diabetes. This estimate was done in 2011. The common symptoms of diabetes include vision problems, increased thirst, increased hunger, and increased urination. Diabetes is generally treated with oral medications, insulin injections, and changes in the diet.

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Hydrochlorothiazide reduces the amount of salt the body absorbs and treats water retention. In diabetes, the blood sugar level is high. Diabetes can increase the risk of stroke, blindness, and heart disease. Knowing and understanding how hydrochlorothiazide affects the body is important since adverse reactions can be caused when certain medications are combined with diuretics.

Insulin acts on the liver, muscle, and fat tissues. The uptake of glucose is enhanced in the liver by the insulin and the formation of new glucose is prevented. The uptake of insulin is stimulated by insulin in the muscle and fat cells and the glucose is prevented from forming its metabolites in the fat and muscle tissues. Insulin performs all these functions by binding to its receptor and a protein.

After binding, it starts off a signal, which stimulates several actions. It increases the number of glucose transport, protein, and enzyme proteins. The glucose transport protein is dependent on potassium, and if it becomes less, then the transport of glucose and insulin secretion is inhibited, which results in higher levels of glucose in the blood. Moreover, if the factors that transport glucose to the liver, muscle, and fats are affected, it will increase the blood pressure.

Diuretics and Hydrochlorothiazide

Hydrochlorothiazide is a diuretic drug. It is used to treat fluid retention, which may happen due to kidney problems, diabetes, heart disease, and other disorders. Since diuretics help remove excess fluid from the body in the form of urination, they are also sometimes called as water pills. They help lower blood pressure and swelling.

Hydrochlorothiazide is a type of diuretic that treats water retention by reducing the body's ability to absorb sodium. Thus, hydrochlorothiazide is regarded as a thiazide diuretic. This medication is prescribed in cases of high blood pressure, kidney disease, and congestive failure. Patients taking this medication have reported complaints of mild stomach pain, diarrhea, constipation, and blurred vision. Seek immediate medical help if you experience any of the following severe symptoms:

  • Severe allergic reactions
  • Hives
  • Trouble breathing
  • Swelling of the face, throat, and lips


The advantages of hydrochlorothiazide are:

  • It is not expensive.
  • Research has shown that diuretics can work effectively by reducing the risk of heart attack and stroke.

Some of the drug's side effects include:

Hydrochlorothiazide and Diabetes

There have been reports of patients with hypertension who are being treated with hydrochlorothiazide. Research has revealed that people with hypertension and taking hydrochlorothiazide could be at an increased risk of developing type 2 diabetes due to depleted levels of potassium. Previous research has shown that thiazide treatment causes the potassium levels to drop and increases diabetes risk. 

Recent research shows that there is a link between the drop in potassium levels and an increase in the risk of diabetes. However, it has been suggested that this medication can be safely used as long as the doctors regularly monitor the condition of their patients, especially their potassium level. It has been speculated that thiazide-induced diabetes can be prevented by taking potassium supplements.

High blood pressure is a risk factor for type 2 diabetes, but there are some medications used to treat hypertension that can increase the risk of developing diabetes. These drugs block the reabsorption of sodium in the kidney and treat hypertension. Potassium is lost in the urine during the treatment process, which results in hypokalemia, a condition in which potassium levels in the blood are low. Hence, people taking thiazide diuretics also need to take potassium supplements to achieve normal potassium levels in the body. 

It has been noted that glucose uptake into the fat tissues and muscles as well as the secretion of insulin are all closely related to potassium levels. Many studies have been conducted to see the effects of thiazide on blood glucose levels. A majority of the studies have reported that thiazide tends to elevate the blood glucose level.

A recent study called Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) reported that those who took thiazide diuretics had a slightly higher chance of developing diabetes. It was also noted that those who took thiazide diuretics for the treatment of high blood pressure were at increased risk compared to the ones who took other drugs. However, taking other alternative drugs is quite difficult since thiazide is one of the high-class medications that can be very effective when it comes to treating high blood pressure in people with diabetes.

Further studies also showed that people taking thiazide were doing well on the medication, but at the same time, had a small increase in their blood glucose level. Further studies in Nurses' Health Study, Nurses' Health Study II, and Health Professionals Follow-Up Study have shown that the risk of developing diabetes with this medication in older women is 20 percent, 51 percent in younger women, and 30 percent higher in those individuals who take this drug.  Studies have also shown that by correcting the potassium levels in the blood, the blood glucose levels can be controlled.

Studies revealed that the risk of a new-onset diabetes was dependent on the dose of hydrochlorothiazide. A substantial risk of impairing the glucose level was found when the given hydrochlorothiazide dose was 25 mg. It was found that by changing the diuretic therapy, it was possible to reverse the negative effect. In one study, it was found that those subjects who took hydrochlorothiazide experienced an improvement in the response of insulin and glucose when they switched from hydrochlorothiazide to verapamil.

It was noted that the 2-hour glucose level using OGTT at six months reduced from 154 mg/dL at baseline to 131 mg/dL. It was also reported that initially, six patients had diabetes, but when they switched from diuretic to trandolapril or verapamil, the number was reduced to half. However, it was also noted that to some extent, the blood pressure was also compromised. The blood pressure was noted to increase from 128 mmHg to 137 mmHg. Even though diuretics are cheap and beneficial, their use must be taken into consideration since they can induce diabetes. 

The use of hydrochlorothiazide is limited due to the risk of diabetes and hyperglycemia that may develop later. Studies have shown a 25-30 percent increase in diabetes when hydrochlorothiazide is used. At the annual meeting of the European Society of Cardiology (ESC), a research study was presented, which discussed the use of the combination of amiloride-hydrochlorothiazide. Amiloride is a potassium-sparing diuretic. It is combined with a diuretic hydrochlorothiazide.

These diuretics were combined because it was observed that the use of hydrochlorothiazide caused changes in the glucose level, which was linked to changes in potassium levels. In one study, some patients only took amiloride, hydrochlorothiazide, and a combination of both diuretics. These patients were treated for uncontrolled hypertension. In the end, all of the patients' blood pressure levels, potassium levels, and glucose levels were measured.

It was found that glucose metabolism was linked to potassium levels. When measured at 12 and 24 weeks, hydrochlorothiazide alone seemed to increase OGTT (oral glucose tolerance test) levels. For patients who only took amiloride, it decreased the 2-hour OGTT levels. Moroever, by using amiloride alone and hydrochlorothiazide alone, the systolic blood pressure decreased by nearly 14 mmHg.

For patients who took the combined medication, they had a decrease in their blood pressure levels by 17.4 mmHg. It was found that the effect of potassium levels was neutral. Thus, the effect on the glucose level was also neutral. It was concluded that the combined use of the medication could be beneficial in treating high blood pressure. At the same time, due to the changes in the potassium levels, the combined use of medication would limit the risk of the patients to develop diabetes. Further research suggests that more thought would be needed when it comes to finding how diuretics can be used in a better way for patients with hypertension.

Practically, a lower dosage of hydrochlorothiazide is recommended due to its increased risk of diabetes and hyperglycemia. Studies have revealed that hydrochlorothiazide could be combined with the potassium-sparing diuretic amiloride to nullify the effect of its changes in the blood glucose level. The combination of both diuretics had a reduction in the systolic blood pressure by 17.4 mmHg. It was also noted that it did not have any effects on blood glucose levels.

A study was published in the October 2009 edition of Cell Biochemistry and Function, and noted that when hydrochlorothiazide was combined with a diet containing high fat, it caused an increased in the glucose levels. The blood lipid and blood glucose readings also increased. The probable reason for the increase is that hydrochlorothiazide causes less insulin to be released. In such cases, the dosage of oral medications and insulin injections may need to be changed by the physicians, especially in patients who are taking hydrochlorothiazide. 


The side effects associated with hydrochlorothiazide are dizziness, loss of balance, and fainting due to the sudden rise in blood pressure. Moreover, it could cause sensitivity in patients with asthma and other breathing disorders. It is important to tell your doctor if you have a history of asthma, breathing disorders, or if you currently have these conditions. The same reactions with hydrochlorothiazide may be experienced by those who are allergic to sulfa drugs.

Those who are on hydrochlorothiazide therapy should be checked for kidney function by prescribing blood work. Adverse reactions associated with hydrochlorothiazide are low blood pressure, yellowing of the eyes or skin, and muscle cramps. Thus, do not take hydrochlorothiazide unless it is prescribed by a physician.

Always consult your doctor if you have any problems with the blood pressure medications that you are taking.