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 diabet
