How can beta-blocker drugs mask hypoglycemic symptoms?

These medicines are designed to blunt the β-effect of adrenalin and related substances. Hence, if hypoglycemia occurs in someone who is using this type of drug, he/she may not experience the typical adrenergic warning symptoms such as tremor and palpitations. Again, the result is hypoglycemic unawareness. Beta blockers will also prevent adrenalin from stimulating the liver to make glucose, and therefore may make the hypoglycemia more severe and/or more protracted.