Question

A nurse is counseling a patient who will begin taking propranolol [Inderal], 40 mg, PO, three times daily. The patient has angina pectoris and Type 2 diabetes mellitus. He will be taking insulin and oral hypoglycemic medications along with the propranolol.. The nurse cautions the patient to check his blood sugars more frequently because: Question 18 options:

a) the beta blocker inhibits p450 enymes, resulting in increased blood levels of oral hypoglycemic drugs

b) beta blockers are p450-inducing drugs, and the propranol will decrease levels of the oral hypoglycemic medications increasing the patient's risk for hyperglycemia

c) the beta blocker can blunt tachycardia and anxiety, which are signs that alert the patient to episodes of hypoglycemia

d) the beta blocker antagonizes insulin receptors making blood sugar control more difficult.

Answer 1

Propanlol is a non selective beta blocker.Beta blockers are the class of drug which act on the beta adrenergic receptors present in the body.On acting on those receptors they competitively block the endogenous adrenaline and nor adrenaline.propanolol acts on all the three Beta-1,2,&3 receptors.beta-1 is located on heart,beta-2 is located in lungs,git,liver and beta-3 is located on fat cells.So by acting on all these receptors propanlol block the receptors and weaken the effect of stress hormones that is adrenaline and nor adrenaline.

In a condition like hypoglycemia which can be caused by oral hypoglycemics there will be stress response by the body which will release catecholamines.But propanlol competitively inhibit the binding of catecholamines and hence mask the symptoms of hypoglycemia like tachycardia, palpitations, anxiety etc.So there is a need to check the blood sugar levels by the nurse so that the patient doesn't get a hypoglycemic shock which may be very fatal.

So the correct answe should be Option C.

Option A and B states propanlol as p450 enzyme inducer or inhibitor but propanlol is a p450 enzyme substrate and neither an inducer nor a substrate.so these options ho wrong.

Non selective beta blockers like carvedilol and propanlol are shown to improve insulin sensitivity so the option D is also not true.