Pressure medications may cause diabetes

Maxwell Adeyemi

IT IS common knowledge that there is a growing number of our population, young and old, that are hypertensive. There is also an increasing incidence of people developing diabetes and there is the possibility of people with both ailments occurring together.

What is emerging is that many people who are hypertensive are also becoming diabetic even though they may not have the traditional risk factors for diabetes.

A major reason now being advanced is that some drugs used in the treatment of high blood pressure might cause diabetes.

Beta-blockers

The class of high blood pressure medication known as beta-blockers are a major culprit. Potential mechanism by which beta-blockers may contribute to the development of diabetes include: weight gain, attenuation of the beta receptor, mediated release of insulin from the pancreatic beta cells, and decreased blood flow through the microcirculation in skeletal muscle tissues, which causes decreased insulin sensitivity and glucose utilisation.

Beta-blockers such as inderal (propanolol) and tenormin (atenolol) increase the risk of diabetes by nearly 30 per cent. However, beta-blockers are cheap and their cardiovascular benefit might outweigh the risk of diabetes for some people, making them an option for people who cannot afford other medications. Hence they can still play an important role in the treatment of people with high blood pressure and heart disease.

Thiazides

Thiazide diuretics, popularly known as “water pills,” are often prescribed to control blood pressure. However, they can promote hyperglycemia and, in some cases, contribute to new onset of diabetes.

The mechanism of how this occurs is postulated to involve worsening of insulin resistance, the inhibition of glucose uptake and decreased insulin release. In addition, thiazide diuretics can downregulate certain chemical receptors, thereby decreasing insulin release in addition to activating the renin-angiotensin-aldosterone system, thus resulting in high levels of aldosterone and consequently causing hyperglycemia.

These drugs have been implicated in contributing to new onset of diabetes in as few as 9-18 weeks of therapy initiation.

Hypertension

linked to diabetes

About half the people with essential hypertension are insulin resistant. This insulin resistance is associated with impaired insulin signalling, impaired fibrinolysis and a complicated inflammatory cascade in the body.

Insulin is a pleiotropic hormone that plays a pivotal role in the development of hypertension, diabetes and the metabolic syndrome.

The inflammatory markers (chemicals of inflammation) in the body are increased in patients with hypertension, diabetes and metabolic syndrome, and they predict the development of these diseases.

Hypertension, diabetes and even obesity not only share common pathophysiologic pathways, but also common susceptibility genes, and the development of one could often trigger the progression to the other.

While these medications are incriminated in the development of diabetes, they do have their role in the treatment of hypertension and hypertensive heart diseases and should not be discarded unilaterally without discussion with your healthcare provider.

In most cases, the health benefits and the risks are discussed and your doctor will make the best decision in the overall interest of the patient. It is, however, very important that you are informed about these risks by your doctor, nurse or pharmacist so that you are better able to make informed decisions and be actively involved in the management of your health situation.

In cases where alternative medications can be used, many patients have elected to use such available options after discussion with their physician.

As for the patients who are hypertensive and obese, the inflammatory pathophysiology involved in these conditions contribute significantly and is intrinsically connected to the development of diabetes. It is therefore beneficial to control these health challenges in order to minimise the risks.

Diabetes and high blood pressure are two important and growing problems which increase a person’s chance of developing an array of other serious health complications, including heart attacks and strokes. The two are inter-connected and lowering blood pressure could be a powerful way to reduce the risk of developing diabetes.

It is also evident that different commonly used drugs for lowering blood pressure have very different effects on the risk of diabetes. Doctors should therefore consider the patient’s risk of developing diabetes when choosing an anti-hypertensive drug to lower their blood pressure.

Reducing a person’s high blood pressure has the benefit of reducing the risk of developing diabetes, while some medications can raise the risk of diabetes. Researches have also shown that some classes of high blood pressure drugs can protect against diabetes. The Angiotensin-converting enzyme inhibitors (ACE inhibitors such as enalapril, lisinopril, captopril perindopril), the Angiotensin receptor blockers (ARBs such as irbesartan, candesartan and losartan) have been found to reduce the risk of diabetes by as much as 16 per cent.

So in addition to the medications that may be needed to control blood pressure being chosen wisely, it is important that lifestyle changes such as dietary adjustment, physical activity, weight loss and avoidance of certain habits like smoking and alcohol abuse be cultivated.

Contact Dr Maxwell on 3631807 or 7575411