When blood sugar is falling, the stopper built into the body is the release of glucagon from the alpha cells of the pancreas which stimulates the release of glucose from the liver (but only if your adrenaline is flowing). However, when hypoglycemia is due to injected insulin - the stopper isn't entirely in place. Scientists explain how epinephrine (adrenaline) plays a major role in regulating glucose in times of low blood sugar and how this response could be adversely affected by the use of beta-blockers.
During insulin-induced hypoglycemia in dogs, the roles of adrenaline and glucagon were evaluated. The dogs fasted overnight to remove excess glucose from the blood. The dogs also had their adrenal glands removed. The adrenal glands are the source of adrenaline. Adrenaline is released into the bloodstream in response to physical or mental stress,to initiate the stimulation of glucose, among many other functions. Adrenaline and insulin were released at two different rates: a basal rate or a variable rate to simulate an adrenaline response. When the blood sugar fell to 42 mg/dL, the dogs in the basal rate group failed to release glucagon, but the simulated adrenaline response group increased normally. The liver response to releasing glucose fell in the basal group but increased in the simulated adrenaline response group. The researchers conclude that adrenaline must be responsible for this critical response to insulin-induced hypoglycemia.
Beta blockers are a common class of prescription drugs that counteract the stimulatory effects of adrenaline. Diabetics who inject insulin and take beta-blockers should be extra cautious of hypoglycemia. Hypoglycemic unawareness is already established for diabetics injecting GM insulin (genetically modified human insulin). Given the side effects of beta blockers, there is greater reason to be more aware of hypoglycemis unawareness -- yes, oxymoron. Those individuals who are on the brink of diabetes should avoid beta-blockers at all costs, according to a study in The Lancet (January 2007) beta-blockers used for hypertension increase a patient's risk of developing diabetes.
1. This is a complicated problem often seen and experienced in T1DM.
On one hand, the person is totally Insulin-Dependent with rDNA and as you say, does interfere with Hypoglycemia Awareness because of the missing C-peptide. That along with the Longevity of the Diabetes will create a further Unawareness in Hypoglycemia.
Now, if the person has an elevated BP(Blood Pressure), which is very common among people w/Diabetes as well as other Cardio-related events, then in order to be Cardio-protective as well as treat the Blood Pressure, a Beta-Blocker is usually prescribed.
So we now have 3 scenarios that each will contribute to blocking out Hypoglycemia Awareness. If all three variables are involved together, than the risk of Unconsciousness/related-injury/Morbidity increases to a very high level.
This is a hard call to make because the Heart has to be treated and protected as well(Beta-Blocker).
It is another Risk-Benefit problem so often found in Medicine.
Posted at 10:05PM on May 19th 2007 by BetterCell